Updating State Residential Building Energy Efficiency Codes, 54131-54142 [2010-22062]
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Federal Register / Vol. 75, No. 171 / Friday, September 3, 2010 / Notices
Information regulations at 10 CFR
1004.11.
VII. Approval of the Office of the
Secretary
The Secretary of Energy has approved
publication of this preliminary
determination.
Issued in Washington, DC, on August 26,
2010.
Cathy Zoi,
Assistant Secretary, Energy Efficiency and
Renewable Energy.
[FR Doc. 2010–22060 Filed 9–2–10; 8:45 am]
BILLING CODE 6450–01–P
DEPARTMENT OF ENERGY
[Docket No. EERE–2010–BT–DET–0030]
RIN 1904–AC17
Updating State Residential Building
Energy Efficiency Codes
Office of Energy Efficiency and
Renewable Energy, Department of
Energy.
ACTION: Notice of proposed
determination.
AGENCY:
The Department of Energy
(DOE or Department) has preliminarily
determined that the 2009 version of the
International Code Council (ICC)
International Energy Conservation Code
(IECC) would achieve greater energy
efficiency in low-rise residential
buildings than the 2006 IECC. Also,
DOE has preliminarily determined that
the 2006 version of the IECC would
achieve greater energy efficiency than
the 2003 IECC. Finally, DOE has
preliminarily determined that the 2003
version of the IECC would not achieve
greater energy efficiency than the 2000
IECC. If these determinations are
finalized, States would be required to
file certification statements to DOE that
they have reviewed the provisions of
their residential building code regarding
energy efficiency and made a
determination as to whether to update
their code to meet or exceed the most
recent code with an affirmative
determination, the 2009 IECC.
Additionally, this Notice provides
guidance to States on how the codes
have changed from previous versions,
how to submit certifications, and how to
request extensions of the deadline to
submit certifications, should the
preliminary determinations be adopted
as final.
DATES: Comments on the preliminary
determinations must be provided by
October 4, 2010.
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SUMMARY:
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You may submit comments,
identified by any of the following
methods:
• Federal eRulemaking Portal: https://
www.regulations.gov. Follow the
instructions for submitting comments.
• E-mail: ronald.majette@ee.doe.gov.
Include RIN 1904–AC17 in the subject
line of the message.
• Postal Mail: Mr. Ronald B. Majette,
U.S. Department of Energy, Office of
Energy Efficiency and Renewable
Energy, Forrestal Building, Mail Station
EE–2J, 1000 Independence Avenue,
SW., Washington, DC 20585–0121.
Please submit one signed paper original.
• Hand Delivery/Courier: Mr. Ronald
B. Majette, U.S. Department of Energy,
Federal Energy Management Program,
Room 6003, 1000 Independence
Avenue, SW., Washington, DC 20585–
0121.
Instructions: All submissions must
include the agency name, Department of
Energy, and docket number, EERE–
2010–BT–DET–0030, or Regulatory
Information Number (RIN), 1904–AC17,
for this rulemaking.
FOR FURTHER INFORMATION CONTACT: Mr.
Ronald B. Majette, U.S. Department of
Energy, Office of Energy Efficiency and
Renewable Energy, Forrestal Building,
Mail Station EE–2J, 1000 Independence
Avenue, SW., Washington, DC 20585–
0121, 202–586–7935. For legal issues
contact Chris Calamita, U.S. Department
of Energy, Office of the General Counsel,
Forrestal Building, GC–72, 1000
Independence Avenue, SW.,
Washington, DC 20585, (202) 586–9507,
e-mail:
Christopher.Calamita@hq.doe.gov.
ADDRESSES:
SUPPLEMENTARY INFORMATION:
I. Introduction
A. Statutory Requirements
B. Background
C. DOE’s Preliminary Determination
Statements
II. Discussion of Changes in the 2003, 2006,
and 2009 IECC
A. 2003 IECC Compared With the 2000
IECC
B. 2006 IECC Compared With the 2003
IECC
C. 2009 IECC Compared With the 2006
IECC
III. Comparison of the 2009 IRC to the 2009
IECC
IV. Filing Certification Statements With DOE
A. State Determinations
B. Certification
C. Request for Extensions
V. Regulatory Analysis
A. Review Under Executive Order 12866
B. Review Under the Regulatory Flexibility
Act
C. Review Under the National
Environmental Policy Act of 1969
D. Review Under Executive Order 13132,
‘‘Federalism’’
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E. Review Under the Unfunded Mandates
Reform Act of 1995
F. Review Under the Treasury and General
Government Appropriations Act of 1999
G. Review Under the Treasury and General
Government Appropriations Act of 2001
H. Review Under Executive Order 13211
I. Review Under Executive Order 13175
VI. Public Participation
VII. Approval of the Office of the Secretary
I. Introduction
A. Statutory Requirements
Title III of the Energy Conservation
and Production Act, as amended
(ECPA), establishes requirements for the
Building Energy Standards Program. (42
U.S.C. 6831–6837) Section 304(b) of
ECPA, as amended, provides that when
the 1992 Model Energy Code, or any
successor to that code, is revised, the
Secretary of the Department of Energy
must determine, not later than 12
months after the revision, whether the
revised code would improve energy
efficiency in residential buildings and
must publish notice of the
determination in the Federal Register.
(42 U.S.C. 6833(a)(5)(A)) The
Department, following precedent set by
the International Code Council (ICC)
and the American Society of Heating,
Refrigerating and Air-Conditioning
Engineers (ASHRAE) considers high-rise
(greater than three stories) multifamily
residential buildings and hotel, motel,
and other transient residential building
types of any height as commercial
buildings for energy code purposes.
Low-rise residential buildings include
one- and two-family detached and
attached buildings, duplexes,
townhouses, row houses, and low-rise
multifamily buildings (not greater than
three stories) such as condominiums
and garden apartments.
If the Secretary determines that the
revision would improve energy
efficiency then, not later than 2 years
after the date of the publication of the
affirmative determination, each State is
required to certify that it has compared
its residential building code regarding
energy efficiency to the revised code
and made a determination whether it is
appropriate to revise its code to meet or
exceed the provisions of the successor
code. (42 U.S.C. 6833(a)(5)(B)) State
determinations are to be made: (1) After
public notice and hearing; (2) in writing;
(3) based upon findings included in
such determination and upon evidence
presented at the hearing; and (4)
available to the public. (See, 42 U.S.C.
6833(a)(5)(C)) In addition, if a State
determines that it is not appropriate to
revise its residential building code, the
State is required to submit to the
Secretary, in writing, the reasons, which
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are to be made available to the public.
(See, 42 U.S.C. 6833(a)(5)(C))
B. Background
The International Code Council’s
(ICC) International Energy Conservation
Code (IECC) establishes national energy
efficiency requirements for buildings. In
1997, the Council of American Building
Officials (CABO) was incorporated into
the ICC and the Model Energy Code
(MEC) was renamed to the IECC. A
previous Federal Register notice, 59 FR
36173, July 15, 1994, announced the
Secretary’s determination that the 1993
MEC increased energy efficiency
relative to the 1992 MEC for residential
buildings. Similarly, another Federal
Register notice, 61 FR 64727, December
6, 1996, announced the Secretary’s
determination that the 1995 MEC is an
improvement over the 1993 MEC.
Finally, Federal Register notice 66 FR
1964, January 10, 2001, simultaneously
announced the Secretary’s
determination that the 1998 IECC is an
improvement over the 1995 MEC and
the 2000 IECC is an improvement over
the 1998 IECC.
C. DOE’s Preliminary Determination
Statement
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2003 IECC
The Department of Energy’s review
and evaluation found that there are not
significant differences in energy
efficiency between the 2003 edition and
the 2000 edition of the IECC. Although
there are a few changes that would
modestly improve the energy efficiency
of residential buildings, there are a
number of changes that reduce energy
efficiency in certain situations. Most of
the changes to the IECC between the
2000 and 2003 editions would not affect
energy efficiency but rather make the
code simpler and clearer for designers,
builders, and code compliance officials
to understand and use. Based on these
findings, the Department has
preliminarily concluded that the 2003
edition of the IECC should not receive
an affirmative determination under
Section 304(b) of ECPA. The
Department preliminarily concludes
that there is a slight improvement in
energy efficiency for many residential
buildings, but this improvement is not
sufficient to merit an affirmative
determination. It should be noted that
DOE is not concluding that the energy
efficiency of the 2003 IECC less
stringent than the 2000 IECC.
2006 IECC
The residential portion of the 2006
IECC has been extensively changed from
that the 2003 IECC. However, the most
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significant changes to the code between
2003 and 2006 simplify the code format
rather than fundamentally changing the
overall (national average) energy
efficiency of the code. Multifamily
buildings, which in the past have had
separate, less stringent thermal
requirements, are an exception. By
eliminating the separate requirements,
the 2006 IECC increased the energy
efficiency of multifamily buildings.
Although the most significant 2006
changes did not directly target
efficiency improvements, the new
format of the code does result in some
energy efficiency differences. The
requirements for any given building
may have increased or decreased based
on the specific location (climate) and
building design. The Department has
preliminarily found that overall the
2006 IECC has a small improvement in
energy efficiency compared to the 2003
IECC. The Department preliminarily
concludes that the 2006 edition of the
IECC should receive an affirmative
determination under Section 304(b) of
EPCA.
2009 IECC
The 2009 IECC has substantial
revisions compared to the 2006 IECC.
Many of these revisions appear to
directly improve energy efficiency, and
the sum results of all changes appear to
result in a significant increase in code
stringency. Therefore, the Department
preliminarily concludes that the 2009
edition of the IECC should receive an
affirmative determination under Section
304(b) of EPCA.
II. Discussion of Changes in the 2003,
2006, and 2009 IECC
A. 2003 IECC Compared With the 2000
IECC
As a whole, the 2003 IECC’s
provisions for energy efficiency in
residential buildings appear largely
unchanged from the 2000 IECC. There
are some changes in the code that can
have a modest effect on energy
efficiency. These are discussed below.
In addition, there is a variety of minor
changes intended to make the code
more concise, more complete, and better
organized, but not more or less
stringent. For example, more specific
requirements have been added for steel
roofs/ceilings and floors to correspond
to those already in the code for steel
walls. Another example is the relocation
of the 51 pages of state maps from the
middle of the code to the back of the
code. Additionally, the performance
path in Chapter 4 of the 2003 IECC
contains a variety of modest
improvements compared to the 2000
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IECC, which creates more concise
requirements.
Changes in the 2003 IECC That Improve
Energy Efficiency
1. Increased Duct Insulation
Requirements
Duct insulation requirements
generally increased in the 2003 IECC.
The 2003 IECC requirements are shown
in Table 1. These are somewhat difficult
to compare to the 2000 IECC
requirements because the latter are more
complex, differing between ducts in
unconditioned spaces and ducts
completely exterior to the building and
distinguishing requirements by the
design temperature difference between
the duct air and the space in which the
ducts are located. The 2000 IECC
requirements for ducts in unconditioned
spaces are shown in Table 2. Assuming
typical supply air temperatures of 55
degrees F for cooling and 95 degrees F
for heating (for heat pumps), the 2000
IECC insulation requirement for supply
ducts in unconditioned spaces is R–5
(minimum) for nearly all cases.
Insulation required by the 2000 IECC for
return ducts in unconditioned spaces
will generally be R–3.3 in warmer
climates and R–5 in colder climates.
For the very common case of supply
ducts in attics, and the case that is likely
to have the greatest impact on energy
use, the 2003 IECC always requires at
least R–8, which exceeds the 2000
IECC’s R–5 requirement. For supply
ducts in other unconditioned spaces,
the 2003 IECC’s requirements exceed
the 2000 IECC’s requirements in all
cases except very warm locations (less
than 1500 heating degree-days), where
the 2003 IECC requires R–4 compared to
the 2000 IECC’s requirement of R–5.
Because supply ducts transport air in its
hottest (or coldest) condition, insulation
has its greatest impact on these ducts.
The 2003 IECC is almost always more
stringent than the 2000 IECC for supply
ducts. This includes all supply ducts in
attics and, based on the distribution of
population 1, more than 80% of ducts in
other unconditioned spaces.
Requirements for return ducts in
attics are slightly more stringent in the
2003 IECC (R–4 vs R–3.3) in the
warmest climates, slightly less stringent
(R–4 vs R–5) in mid climates, and
slightly more stringent (R–6 vs R–5) in
the coldest climates.
1 Estimated from USGS Population Places data
that allows mapping of population to climate
(https://geonames.usgs.gov/domestic/download_
data.htm).
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Research 2 showing the impact on
heating and cooling energy use due to
duct insulation is summarized in Table
3. Based on this research, the
Department estimates that improved
duct insulation in the 2003 IECC will
reduce heating and cooling energy use
by about 1%.
TABLE 1—DUCT INSULATION REQUIREMENTS IN THE 2003 IECC
Insulation R-value (h · ft2 · °F)/Btu
Ducts in unconditioned attics or outside
building
Annual heating degree days base 65°F
Supply
Below 1,500 .....................................................................
1,500 to 3,500 ..................................................................
3,501 to 7,500 ..................................................................
Above 7,500 .....................................................................
Ducts in unconditioned basements, crawl
spaces, and other unconditioned spaces
Return
8
8
8
11
Supply
4
4
4
6
Return
4
6
8
11
0
2
2
2
TABLE 2—INSULATION REQUIREMENTS (R-VALUE, h-ft2-F/BTU) FOR DUCTS IN UNCONDITIONED SPACES IN THE 2000 IECC
Design Temperature Difference (TD) between air temperature in duct
and space in which duct is located (degrees F)
Cooling
TD ≤ 15 ...................................................................................................
40 ≥ TD > 15 ...........................................................................................
TD > 40 ...................................................................................................
None required ................................
3.3 ..................................................
5.0 ..................................................
Heating
None required.
3.3.
5.0.
TABLE 3—HEATING AND COOLING ENERGY SAVINGS (PERCENT) FROM INCREASED DUCT INSULATION
[Atlanta, Natural Gas Heating]
Attic
R–4 to R–6 ..................................................................................................................................
R–6 to R–8 ..................................................................................................................................
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2. Minor Changes to ‘‘Systems Analysis’’
Performance Compliance Method
There are two changes that can
increase the stringency of the
performance path in Chapter 4 of the
2003 IECC in certain cases. First, any
house proposed to use electric
resistance heating must have equal or
lower calculated energy use than a
hypothetical ‘‘standard design’’ that uses
a more efficient electric air source heat
pump. This change makes the
performance approach much more
stringent for designs that have electric
resistance heating. However,
compliance can be achieved for these
designs using the prescriptive
compliance methods in Chapters 5 and
6, thereby bypassing the increased
stringency of the performance path.
Second, a provision has also been
added requiring that the least efficient
orientation in terms of energy use be
assumed for a proposed group of
residences with identical designs.
Therefore, in a development where the
same design is built on multiple lots
facing various directions, the
compliance analysis must be based on
the least advantageous orientation. In
2 Triedler, B., R. Lucas, M. Modera, J. Miller.
1996. Impact of Residential Duct Insulation on
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most of the United States, this is the
orientation that points the most window
area toward a westerly direction,
maximizing solar heat gains in summer
afternoons and therefore increasing air
conditioning energy use. Because
proposed building designs must have a
calculated annual energy use equal to or
less than that of a home with window
area equally distributed toward the four
cardinal directions, the requirement to
assume the least efficient orientation
effectively makes the code more
stringent because the increased energy
use from the least efficient orientation
must be offset by improved energy
efficiency. This requirement in the 2003
IECC will have only modest average
impact because it affects only the
performance approach and identical
house designs used repeatedly in a
development.
B. Changes in the 2003 IECC That
Decrease Energy Efficiency
1. Sunroom Additions
A special set of requirements has been
added to Table 502.2.5 of the 2003 IECC
for sunroom additions having a floor
area of less than 500 ft2 (46.5 m2).
Sunroom additions are permitted to
HVAC Energy Use and Life-Cycle Costs to
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Basement
2.3
1.4
Crawlspace
1.6
0.9
1.8
1.1
have ceiling, wall insulation, and
window U-factor requirements that are
typically less stringent than the
requirements for all other types of
residential construction. These special
requirements for sunrooms only apply
to additions to existing dwellings, not to
sunrooms that are built as part of a new
dwelling. In the 2000 IECC, there were
no special requirements for sunroom
additions; they had to meet the same
requirements as other residential
construction. To qualify for the less
stringent requirements in the 2003 IECC,
the sunroom addition must be capable
of being controlled as a separately
heated and cooled zone. Additionally,
new walls, doors or windows between
the sunroom and the house must meet
the envelope requirements of the IECC.
Finally, the glazing area must exceed
40% of the gross area of the exterior
walls and roof to qualify as a sunroom
in the IECC.
Testing with the DOE–2 simulation
tool indicates that for a 500 ft2 sunroom,
the less stringent 2003 requirements
could add about $200 to the annual
energy costs in Chicago if the sunroom
is both heated and cooled all year.
Impacts are much smaller in Houston,
Consumers. American Society of Heating,
Refrigerating, and Air-Conditioning Engineers.
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about $10 added energy costs. However,
this increase in energy consumption is
mitigated (on average) by several factors.
First, the requirements apply to a very
small fraction of all new residential
construction. The Wall Street Journal
Online (June 3, 2003) reports three
billion dollars worth of sunroom
construction each year, or less than one
percent of all residential construction
expenditures. But that fraction includes
new construction as well as additions,
so the fraction representing sunroom
additions is less than 1%. Second, it is
expected that many sunrooms will not
be maintained at comfort conditions all
year, further reducing the overall
impact. Finally, because the 2003 IECC
requires that the sunroom be thermally
isolated from the rest of the house and
that walls, windows, and doors between
the sunroom and house meet the code’s
envelope requirements, the thermal
impact when these spaces are not
actively conditioned is negligible.
Therefore, the overall impact of this
reduction in stringency to national
energy use is expected to be extremely
small.
2. Climate Zone Maps
The IECC contains prescriptive
envelope requirements (insulation Rvalues and glazing U-factors) in Chapter
6 and Section 502.2.4 of the code. In the
2000 IECC, only the heating degree-days
for the city where the housing was to be
built could be used to determine the
applicable prescriptive envelope
requirements. In the 2003 IECC, the
heating degree-days can still be used to
determine the requirements, but
additionally the designer/builder can
use the climate zones provided in the
state maps in the IECC. For most
locations, the Chapter 3 climate zones
and heating degree-days lead to the
exact same requirements. Using the
climate zones in the maps instead of the
heating degree-days will allow about
10% of cities nationwide to have a less
stringent set of prescriptive
requirements. However, about 20% of
cities nationwide will have more
stringent requirements when the climate
zones are used with the prescriptive
requirements. If the designer/builders
select to use the climate zone maps in
the 10% of cities where it lowers
requirements but not in the 20% of
locations where it raises requirements,
the 2003 code effectively is less
stringent. However, DOE believes code
users will make use of the climate zone
maps even in many of the locations
where they raise requirements. It is
doubtful most code users will go
through the level of effort of
determining which method of
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determining climate based requirements
may give less stringent requirements. In
fact, DOE believes most users will not
even be aware of these differences, but
will prefer the climate zone maps
because of their simplicity. The
REScheck compliance materials
developed by the U.S. Department of
Energy utilize the same heating degree
day based requirements for both the
2000 and 2003 IECC.
3. Increased U-Factor for Skylight
Replacements
The maximum U-factor for skylight
replacements in existing buildings
(Section 502.2.5 of the IECC) is raised
from a U-factor of 0.50 to a U-factor of
0.60 for locations above 1,999 heating
degree-days. A higher U-factor reduces
energy efficiency.
C. Net Impact on Energy Efficiency
The change in the 2003 IECC that is
expected to have the greatest impact on
energy efficiency for the nation is the
improved duct insulation because a
majority of new residential buildings
have ducts that pass through attics,
crawl spaces, unheated basements and
other spaces where the IECC requires
duct insulation. The improved duct
insulation in the 2003 IECC is estimated
to save about 1% of heating and cooling
costs.
The ‘‘Systems Analysis’’ performance
compliance method is a less commonly
used compliance method and the
modest energy savings from the
improvements in this optional
compliance method can easily be
bypassed by choosing a different
compliance method. Because this
approach is optional, it is impossible to
calculate the cumulative effect these
code changes will have on energy
efficiency. DOE believes that the
changes to the system analysis method
are insufficient to sway the decision on
whether the determination is affirmative
or not.
The changes that reduce energy
efficiency for sunroom additions and
skylight replacements are not
considered to have substantial impacts
on national energy use as they do not
apply to new buildings and only apply
to specific types or retrofits and
additions to existing buildings. The
skylight U-factor change is only a
modest reduction in energy efficiency
and sunroom additions are a small
fraction of the residential construction
market.
The addition of the climate zone maps
in the 2003 IECC as an option to using
city-specific heating degree-day data
allows for the possibility of
preferentially lowering thermal
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envelope requirements in about 10% of
all national locations. However, it is
difficult to exploit this change because
the code user must perform relatively
complex calculations rather than using
the popular and user-friendly REScheck
software.
DOE preliminarily concludes the
improved duct insulation will slightly
improve energy efficiency in most
houses. However, the reductions in
energy efficiency for skylight
replacements and sunroom additions
are expected to at least partially offset
these savings from a national energy
total use perspective. The vast majority
of all requirements in the IECC are
unchanged from 2000 to 2003. For these
reasons, DOE initially finds insufficient
improvements in the 2003 to merit an
affirmative determination.
B. 2006 IECC Compared With the 2003
IECC
The residential portion of the IECC in
general and the building thermal
envelope (ceilings, walls, doors,
windows, foundations, etc.)
requirements in particular were
completely restructured from 2003 to
2006. This resulted in the code
becoming much shorter and simpler, its
volume reduced from 38 pages to 9
pages. The climate basis on which
envelope requirements depend was
completely reworked. The 2003 IECC
has envelope requirements that vary
continuously with heating degree-days
(HDD),3 or with 17 HDD zones
(geographically-defined based on
counties, roughly following 500–HDD
bins). In contrast, the 2006 IECC has
eight geographically-defined climate
zones with all borders set on county
boundaries.
A major change to envelope
requirements was the combining of
separate requirements for two building
categories (one- and two-family
dwellings, and all other low-rise
residential buildings). The 2006 IECC
requirements are the same for all lowrise residential building types, which
has the effect of increasing the energy
efficiency of the other low-rise
buildings. Also eliminated were nine
related tables that provided predefined
packages of thermal transmittance
prescriptive requirements (glazing,
ceiling-roof, exterior wall, floor over
unconditioned space, basement and
crawl space walls, and floor slab on
grade) for different window to wall area
ratios (WWR). In their place, the 2006
IECC provides a single table of
predefined packages of thermal
3 Some compliance paths defined requirements
based on 17 ‘‘zones’’ based on HDD ranges.
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transmittance prescriptive requirements
that do not vary with WWR.
Table 4 shows a comparison of major
prescriptive envelope requirements for a
single-family house at a typical 15%
WWR. The requirements for the 2003
IECC will differ from those shown in
Table 4 for other WWRs and for
multifamily buildings. The 2006 IECC
climate zones do not exactly map to the
2003 IECC zones. Table 5 shows a more
detailed estimate of how residential
construction maps from the 2006 IECC
compare to the 2003 IECC climate
zones.
TABLE 4—COMPARISON OF THE 2003 IECC AND 2006 IECC ENVELOPE THERMAL COMPONENT PRESCRIPTIVE CRITERIA
FOR ONE- AND TWO-FAMILY DWELLINGS AT 15% WINDOW AREA
IECC
climate
zone
Maximum
Heating degree days
2003
1
Glazing
U-factor
2006
1 ........
2
Minimum
2003
Ceiling R-value
2006
2003
2006
Wall R-value
2003
2006
Floor R-value
2003
2006
0–499 .................................................
Any
1.20
R–13
R–30
R–11
R–13
R–11
R–13
500–999 .............................................
0.90
0.75
R–19
R–30
R–11
R–13
R–11
R–13
1,000–1,499 .......................................
0.75
0.75
R–19
R–30
R–11
R–13
R–11
R–13
4 ........
1,500–1,999 .......................................
0.75
0.75
R–26
R–30
R–13
R–13
R–11
R–13
5 ........
2,000–2,499 .......................................
0.65
0.65
R–30
R–30
R–13
R–13
R–11
R–19
2,500–2,999 .......................................
0.60
0.65
R–30
R–30
R–13
R–13
R–19
R–19
7 ........
3,000–3,499 .......................................
0.55
0.65
R–30
R–30
R–13
R–13
R–19
R–19
8 ........
3,500–3,999 .......................................
0.50
0.40
R–30
R–38
R–13
R–13
R–19
R–19
4,000–4,499 .......................................
0.45
0.40
R–38
R–38
R–13
R–13
R–19
R–19
10 ........
4,500–4,999 .......................................
0.45
0.40
R–38
R–38
R–16
R–13
R–19
R–19
11 ........
5,000–5,499 .......................................
0.45
0.35
R–38
R–38
R–18
R–19
R–19
R–19/30
12 ........
5,500–5,999 .......................................
0.40
0.35
R–38
R–38
R–18
R–19
R–21
R–19/30
6,000–6,499 .......................................
0.35
0.35
R–38
R–38
R–18
R–19
R–21
R–19/30
6,500—6,999 .....................................
0.35
0.35
R–49
R–38
R–21
R–19
R–21
R–19/30
7,000–8,499 .......................................
0.35
0.35
R–49
R–38/49
R–21
R–19
R–21
R–21
2 ........
3 ........
2
6 ........
3
9 ........
4
13 ........
5
14 ........
15 ........
5
6
16 ........
6
8,500–8,999 .......................................
0.35
0.35
R–49
R–49
R–21
R–21
R–21
R–21
17 ........
7
9,000–12,999 .....................................
0.35
0.35
R–49
R–49
R–21
R–21
R–21
R–21
IECC climate zone
Minimum
Basement wall
R-value
Slab perimeter
R-value and
depth feet
2003
2006
2003
0–499 ........................................................................................
R–0
R–0
R–0
R–0
R–0
R–0
500–999 ....................................................................................
R–0
R–0
R–0
R–0
R–4
R–0
1,000–1,499 ..............................................................................
R–0
R–0
R–0
R–0
R–5
R–0
4 ........
1,500–1,999 ..............................................................................
R–5
R–0
R–0
R–0
R–5
R–0
5 ........
2,000–2,499 ..............................................................................
R–5
R–10/
13
R–0
R–0
R–6
R–5
2,500–2,999 ..............................................................................
R–6
R–10/
13
R–4,2
R–0
R–7
R–5
3,000–3,499 ..............................................................................
R–7
R–10/
13
R–4,2
R–0
R–8
R–5
Heating degree days
2003
2006
1 ........
1
2
2 ........
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3 ........
6 ........
7 ........
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Crawl space
wall R-value
2003
2006
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Federal Register / Vol. 75, No. 171 / Friday, September 3, 2010 / Notices
IECC climate zone
Minimum
Basement wall
R-value
Slab perimeter
R-value and
depth feet
2003
2006
2003
2006
3,500–3,999 ..............................................................................
R–8
R–10/
13
R–5,2
R–10,2
R–10
R–10
4,000–4,499 ..............................................................................
R–8
R–10/
13
R–5,2
R–10,2
R–11
R–10
10 ........
4,500–4,999 ..............................................................................
R–9
R–10/
13
R–6,2
R–10,2
R–17
R–10
11 ........
5,000–5,499 ..............................................................................
R–9
R–10/
13
R–6,2
R–10,2
R–17
R–10
12 ........
5,500–5,999 ..............................................................................
R–10
R–10/
13
R–9,4
R–10,2
R–19
R–10
6,000–6,499 ..............................................................................
R–10
R–10/
13
R–9,4
R–10,2
R–20
R–10
6,500–6,999 ..............................................................................
R–11
R–10/
13
R–11,4
R–10,2
R–20
R–10
7,000–8,499 ..............................................................................
R–11
R–10/
13
R–13,4
R–10,2
R–20
R–10
Heating degree days
2003
2006
8 ........
9 ........
4
13 ........
5
14 ........
15 ........
5
6
Crawl space
wall R-value
2003
2006
16 ........
6
8,500–8,999 ..............................................................................
R–18
R–10/
13
R–14,4
R–10,4
R–20
R–10
17 ........
7
9,000–12,999 ............................................................................
R–19
R–10/
13
R–18
R–10,4
R–20
R–10
TABLE 5—PERCENTAGE OF HOMES IN EACH 2006 IECC CLIMATE ZONE THAT WOULD HAVE BEEN IN EACH 2003 IECC
CLIMATE ZONE
2006 IECC climate zone
2003 IECC climate zone
1
srobinson on DSKHWCL6B1PROD with NOTICES
1 ...............................................................
2 ...............................................................
3 ...............................................................
4 ...............................................................
5 ...............................................................
6 ...............................................................
7 ...............................................................
8 ...............................................................
9 ...............................................................
10 .............................................................
11 .............................................................
12 .............................................................
13 .............................................................
14 .............................................................
15 .............................................................
16 .............................................................
17 .............................................................
18 .............................................................
19 .............................................................
100
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
The Department has conducted an
analysis and has preliminarily found
that the 2006 IECC would modestly
increase energy efficiency on an overall
national average basis. This analysis is
summarized below; a technical support
document published in conjunction
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0
0
0
0
0
0
0
22
10
18
28
16
6
0
0
0
0
0
0
0
0
0
0
0
with this Notice contains the full
results. The Department stresses that
this increased energy efficiency is based
on an average across all new residential
buildings. The analysis identified
combinations of locations and building
design where the 2006 IECC would
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slightly reduce energy efficiency;
however, the analysis indicates that the
reductions would be more than offset by
cases where energy efficiency is
improved.
Table 6 provides the overall results of
the comparative analysis of the
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prescriptive envelope requirements of
the 2006 IECC and the 2003 IECC. The
DOE–2 energy simulation software was
used to calculate these values. The 2006
IECC has a 1% average overall national
energy savings. The table shows
zones. In most climates, the two codes
are very nearly equivalent. In climate
zone 5, the 2006 IECC shows a
substantial improvement (about 5%). In
climate zone 3, the 2003 IECC is more
energy efficient (by about 5%).
combined results for single-family and
multifamily construction accounting for
weighted average building
characteristics. Table 6 illustrates
significant regional differences that are
primarily a result of the revised climate
TABLE 6—ANNUAL ENERGY SAVINGS (MBTU) OF 2006 IECC COMPARED TO 2003 IECC FOR PRESCRIPTIVE BUILDING
ENVELOPE REQUIREMENTS
Foundation type
2006 IECC Climate zone
Heated
basement
srobinson on DSKHWCL6B1PROD with NOTICES
Zone 1 ..............................................................................
Zone 2 ..............................................................................
Zone 3 ..............................................................................
Zone 4 ..............................................................................
Zone 5 ..............................................................................
Zone 6 ..............................................................................
Zone 7 ..............................................................................
Average ............................................................................
The analysis underlying the results in
Table 6 does not account for all changes
in the IECC from 2003 to 2006. For
example, the 2006 IECC requires
increased duct insulation in certain
cases. On the other hand, the 2006 IECC
is missing requirements for pool heater
controls (on-off switch) and pool covers
contained in the 2003 IECC. However,
these and a few other miscellaneous
changes do not appear to alter a
determination that the 2006 IECC has a
modest improvement in overall energy
efficiency compared to the 2003 IECC.
The Department expects all heated
pools to have an on-off switch, basic
pool covers are dependent on the
diligent occupant behavior for
removing/covering the pool, and many
homes do not have a pool or may not
heat their pool. Furthermore, the 2003
IECC allows the pool cover requirement
to be bypassed if 20% of the heating
energy is provided by solar heat from
the sun striking the pool surface.
There was one particular issue that
received the most extensive debate
during the 2006 IECC development
process. This issue was how the 2006
IECC sets requirements based on the
window area of a home. There was
considerable concern because a
residential building with unlimited
windows (e.g., an ‘‘all glass’’ house) can
be built without any penalty under the
2006 IECC. This is not the case in the
2003 IECC, where, as the WWR becomes
higher, the code requires improved
performance of windows and/or wall
insulation. However, this effect is offset
in two ways. First, while the 2003 IECC
becomes more stringent at high WWRs,
it also becomes less stringent at low
WWRs, whereas the 2006 IECC does not.
Second, the 2006 IECC increased the
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5.5
1.1
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2.4
0.4
1.4
¥1
0.8
7.3
3.3
4.5
2.7
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0.3
0.9
¥3.3
0.6
4.2
0
0.4
¥0.3
baseline efficiency requirements (Ufactor) of glazing to almost equal thencurrent Energy Star levels in most
locations. The Department’s analysis of
the IECC’s requirements related to
window area indicate that the 2006 code
is not weaker than the 2003 IECC when
the distribution of window areas in all
residential buildings is accounted for.
A major factor influencing the
Department’s preliminary determination
of improved efficiency in the 2006 IECC
is the improvement in energy efficiency
for multifamily housing. The building
envelope requirements in 2006 IECC are
identical for all residential building
types. This is not the case in the 2003
IECC where the requirements for
multifamily building types are
considerably less stringent than those
for one and two-family dwellings. This
is shown in the wall requirements in
Figure 502.2(1) of the 2003 IECC. While
multifamily residential construction has
a much smaller market share than
single-family in terms of number of
dwelling units, there is a nearly
universal improvement in requirements
for multifamily buildings regardless of
building design or climate zone. As
indicated below in the certification
discussion, high-rise (greater than three
stories) multifamily residential
buildings and hotel, motel, and other
transient residential building types of
any height as commercial buildings for
energy code purposes. However, the
building envelope revisions in 2006
IECC would impact residential
buildings such as townhouses, row
houses, and low-rise multifamily
buildings (not greater than three stories)
such as condominiums and garden
apartments.
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0.7
6.3
2.3
3.4
3.3
Average
Percent
savings
0.3
0.9
¥3.4
1.1
5.7
1.4
¥0.4
1
2
3
¥5
1
5
1
0
1
C. 2009 IECC Compared With the 2006
IECC
Each of the major changes in the 2009
IECC that impact energy efficiency is
examined individually below. All but
one of the changes appear to improve
energy efficiency.
1. Changes That Improve Energy
Efficiency
Lighting
The 2009 IECC has a major new
requirement that a minimum of 50% of
all lamps (bulbs, tubes, etc.) be ‘‘high
efficacy,’’ which is defined to include
compact fluorescent lights (CFLs), T–8
or smaller diameter fluorescent tubes, or
other products achieving comparable or
better lumen-per-watt ratings.
Traditional incandescent bulbs do not
meet this requirement. The 2006 IECC
had no lighting requirements for
residential buildings. The Department
estimates that lighting consumed 11.6%
of all primary energy use in residential
buildings in 2006 and that the
requirement in the 2009 IECC could
reduce lighting energy use by about
25%.
Building Envelope Thermal Measures
The 2009 IECC has a number of
changes that improve energy efficiency
in the building envelope. There are
direct increases in prescriptive building
envelope requirements in Tables 402.1.1
and 402.1.3 of the IECC. Table 7 shows
these changes. Additionally, there were
a number of minor improvements,
including establishing an area limit of
24 ft2 on the door exemption from Ufactor requirements.
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TABLE 7—IMPROVEMENTS IN PRESCRIPTIVE ENVELOPE REQUIREMENTS
Component
2006 IECC
Maximum fenestration U-factor (excluding skylights).
Zone 2: 0.75 .....................................................
Zone 3: 0.65 .....................................................
Zone 4: 0.40 .....................................................
0.40 ...................................................................
Zone 2: 0.65.
Zone 3: 0.50.
Zone 4: 0.35.
0.30.
R–13 cavity or R–10 continuous insulation .....
No insulation required ......................................
R–19 cavity or R–15 continuous insulation.
R–13 cavity or R–5 continuous insulation.
R–19 .................................................................
R–20.
R–30 .................................................................
R–38.
Another study from Washington State
concluded: ‘‘Comparisons to air leakage
rates reported elsewhere for homes built
before the implementation of the 1991
WSEC show no significant improvement
by the general population’’ despite years
of training emphasizing duct sealing.5
Numerous other studies around the
nation show substantial duct leakage in
new homes, including those in states
with codes requiring duct sealing. For
example, a 2001 study of 186 houses
built under the Model Energy Code in
Massachusetts reported ‘‘serious
problems were found in the quality of
duct sealing in about 80% of these
houses’’.6 Pressurization tests in 22 of
these houses found an average leakage
to the outside of the house of 183 cfm,
or 21.6% of the system flow, at a
pressure of 25 Pascals.
The energy savings of improved duct
sealing are very substantial. A California
study estimated a sales-weighted state
annual average savings from duct
sealing of 38 therms and 239 kWh for
a 1761 ft 2 house.7 This is based on an
estimated 12% improvement in duct
efficiency based on previous studies
indicating a 12–15% improvement
potential. The Department preliminarily
concludes that the 2009 IECC’s
requirement that duct air leakage meet
an upper limit and be verified by a
pressure test will save significant energy
compared to the 2006 and prior editions
of the IECC.
Improvement in Other Requirements
Maximum fenestration solar heat gain coefficient (SHGC) in Zones 1 through 3.
Basement wall insulation in Zones 6 through 8
Basement wall insulation in northern section of
Zone 3.
Wood-Frame wall insulation (all but basements) in Zones 5 and 6.
Floor insulation in Zones 7 and 8 .....................
Building Envelope Air Leakage
Although the fundamental
requirement to seal all potential sources
of leaks has not changed, the air leakage
control specifications in Section 402.4
of the 2009 IECC are considerably more
detailed than in the 2006 edition,
requiring either a comprehensive
inspection against a checklist of
component sealing criteria or a wholebuilding pressurization test. There is a
new requirement that fireplaces have
gasketed doors to limit air leakage.
Additionally, compliance with Standard
ASTM E283 is now required to limit air
leakage through recessed light fixtures.
The 2006 IECC only required recessed
light fixtures to be sealed but did not
require compliance with the ASTM
standard. This testing of fixtures is
expected to help eliminate energy
consuming leaks through these fixtures,
which can be a very common method of
lighting in kitchens and other rooms in
new houses.
srobinson on DSKHWCL6B1PROD with NOTICES
Duct Leakage Limits and Testing
Requirement
The 2009 IECC contains a new
requirement that buildings with ducts
that pass outside the conditioned space
(for example, if ducts are in
unconditioned attics, garages or
crawlspaces) have the ducts pressure
tested and shown to have a maximum
leakage rate below specified limits.
While the 2006 IECC also requires ducts
to be sealed, the addition of a specific
leakage limit verified by a pressure test
in each new home or retrofit is expected
to substantially reduce leakage in many
if not most cases.
Testing of completed homes in
Washington State where prescriptive
code requirements for duct sealing
apply without any testing to confirm
compliance, ‘‘showed no significant
improvement’’ over non-code homes.4
4 Washington State University. 2001. Washington
State Energy Code Duct Leakage Study Report.
WSUCEEP01105. Washington State University
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Cooperative Extension Energy Program, Olympia,
Washington.
5 Hales, D., A. Gordon, and M. Lubliner. 2003.
Duct Leakage in New Washington State Residences:
Findings and Conclusions. ASHRAE Transactions.
KC–2003–1–3.
6 Xenergy. 2001. Impact Analysis Of The
Massachusetts 1998 Residential Energy Code
Revisions. https://www.mass.gov/Eeops/docs/dps/
inf/inf_bbrs_impact_analysis_final.pdf.
7 Hammon, R. W., and M. P. Modera. 1999.
‘‘Improving the Efficiency of Air Distribution
Systems in New California Homes-Updated Report.’’
Consol. Stockton, California. https://
www.energy.ca.gov/title24/ducttape/documents/
IMPROVE_EFFICIENCY_RES.PDF.
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1. There are a number of changes to
the ‘‘simulated performance alternative’’
compliance path in the 2009 IECC. The
glazing area in the baseline ‘‘standard
reference design’’ was reduced from a
maximum of 18% of the conditioned
floor area to 15%. This results in
increased energy efficiency for any
proposed design having a glazing area of
more than 15%. Because use of this
compliance path is completely optional,
these savings will only occur when the
user chooses this compliance path.
Another change does not directly alter
code stringency in the performance path
but may ultimately result in some
energy savings is the removal of the
option to trade high-efficiency HVAC
equipment for reductions in other
requirements in the code, such as
reduced envelope insulation. Because
building envelopes have substantially
longer lives than HVAC and/or water
heating equipment, energy savings from
envelope improvements may persist for
many more years than comparable
equipment improvements. Also, because
high-efficiency equipment is already the
predominant choice in many markets,
disallowing envelope/equipment tradeoffs is likely to result in improved
overall efficiency in many situations.
2. Changes That Reduce Energy
Efficiency
There is only one change in the 2009
IECC that directly reduces energy
efficiency. Insulation requirements for
many ducts outside the building
thermal envelope are reduced from R–
8 to R–6; exceptions are supply ducts in
attics, which must still have R–8
insulation, and ducts in floor trusses,
which retain the 2006 code’s R–6
requirement.
3. Net Impact on Energy Efficiency
The Department has conducted an
energy simulation analysis of 2009 IECC
compared to the 2006 using the DOE–
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54139
heating and cooling costs. Figure 1
shows the estimated annual energy cost
savings resulting from the 2009 IECC
changes for 14 diverse climates and for
the national average. Actual savings will
vary depending on many factors,
including how well ducts are currently
sealed in the absence of any testing
requirements.
Our analysis indicates that the 2009 IRC
would not equal or exceed the energy
efficiency of the 2009 IECC.
Chapter 11 of the IRC contains energy
efficiency provisions. The IRC allows
compliance with the IECC as an
alternative to complying with Chapter
11. Most of the energy efficiency
requirements in the IRC and IECC are
identical. However, there are several
differences between the two codes that
result in the 2009 IRC having reduced
energy efficiency compared to the 2009
IECC. All the differences are listed
below.
1. The 2009 IECC requires a glazed
fenestration solar heat gain coefficient
(SHGC) of 0.30 or lower whereas the
2009 IRC requires a higher (less
stringent) SHGC of 0.35 or lower, in
climate zones 1, 2, and 3. Further, the
2009 IRC allows impact resistant
fenestration in zones 1 through 3 to
meet an even less stringent SHGC
requirement of 0.40 and less stringent
U-factor requirements in zones 2 and 3.
2. For basement walls, the 2009 IECC
requires either R–15 continuous
insulation or R–19 cavity insulation in
zones 6–8, whereas the 2009 IRC
requires lower (less stringent) R-values
in these zones: R–10 continuous or R–
15 cavity.
3. The 2009 IECC requires R–38 floors
in zones 7 and 8; the 2009 IRC requires
only R–30.
In the past some states have adopted
the 2009 International Residential Code
(IRC) in lieu of the 2009 IECC because
the IRC provides a comprehensive
building construction code (structural,
plumbing, electrical, energy, etc.) in a
single book for one- and two-family
dwellings and townhouses.
Consequently, DOE anticipates that
some states may wish to adopt the 2009
IRC in lieu of the 2009 IECC. In order
to provide technical assistance to States
that may wish to adopt the 2009 IRC,
DOE has evaluated the 2009 IRC to
compare the stringency of its energy
provisions with those of the 2009 IECC.
8 The DOE–2 simulation tool is available at https://
doe2.com/.
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and central electric air conditioning
($.12/kWh) were assumed.
High-efficacy lighting was assumed to
increase from 10% to 50% of all lighting
within the building, reducing lighting
energy use by 26%, or $74 a year.
Savings attributable to the lighting
requirements in the IECC will decrease
as Federal law requires improved light
bulbs in 2012 to 2014. Improved duct
sealing was assumed to save 10% of the
III. Comparison of the 2009 IRC to the
2009 IECC
srobinson on DSKHWCL6B1PROD with NOTICES
2 simulation tool to model 8 a two-story,
single-family house with a crawl space
foundation and a conditioned floor area
of 2,400 ft.2 It was assumed that the
house had 8.5-ft high ceilings, a ceiling
area (bordering the unconditioned attic)
of 1,200 ft 2, a gross exterior wall area of
2,380 ft2, and a window area of 357 ft 2
(15% of the wall area) equally oriented
north, south, east, and west. Heating
with a natural gas furnace ($1.20/therm)
54140
Federal Register / Vol. 75, No. 171 / Friday, September 3, 2010 / Notices
4. The 2009 IECC limits the allowance
for R–30 insulation in ceilings without
attics to 500 ft2 or 20% of the total
insulated ceiling area, whichever is less.
The 2009 IRC limits the allowance to
500 ft2 without regard to the total
ceiling area. Thus, under the 2009 IRC
some smaller homes will have less
efficient ceilings.
The 2009 IRC differs from the 2009
IECC in some ways that, although they
do not reduce the stringency of code
requirements, have the potential to
result in increased energy consumption
in certain situations:
1. Both the IRC and IECC allow for
‘‘trade-offs’’ by which the efficiency of
one building component can be lowered
in trade for higher efficiency in another.
The 2009 IECC limits the extent to
which glazing properties can be reduced
in such trade-offs. The 2009 IECC sets
a trade-off ‘‘cap’’ on SHGC at a maximum
of 0.50 in climate zones 1, 2, and 3 and
a cap on U-factor trade-offs of U–0.48 in
zones 4 and 5 and U–0.40 in zones 6,
7, and 8. These caps are not present in
the 2009 IRC. As these caps do not
increase stringency of the code (but
rather restrict trade-off options), there is
no direct impact on annual energy
consumption or cost. There may,
however, be some impacts on occupant
comfort and/or resistance to moisture
condensation, either of which could
possibly induce occupants to increase
energy consumption, for example by
raising thermostat set points.
2. The air barrier and insulation
inspection requirements differ slightly
between the codes. The 2009 IECC
requires checking that ‘‘Air-permeable
insulation is inside of an air barrier’’
(right column in the first row). The 2009
IRC is missing this, which could result
in insulation on the exterior side of an
air barrier being exposed to windinduced air movement that reduces its
effective R-value.
3. The definitions of ‘‘conditioned
space’’ are different between the two
codes, which, depending on local
officials’ interpretations, could result in
different portions of a building being
deemed conditioned and hence subject
to the code’s envelope requirements.
4. The three labels ‘‘mandatory,’’
‘‘prescriptive,’’ and ‘‘performance’’ are
used to label many sections in the 2009
IECC, but are not used at all in the 2009
IRC. The provisions that are mandatory
are always required while prescriptive
provisions can be traded off as long as
overall home energy efficiency is not
decreased. Thus the 2009 IRC may
permit trading down the efficiency of
some components with the potential to
induce increased energy consumption
as described above.
5. The 2009 IRC (section N1101.1,
‘‘Scope’’) states that Chapter 11 (Energy
Efficiency) does not apply to portions of
the building envelope that do not
enclose conditioned space. Section
101.5.2 of the IECC is more specific,
exempting only building thermal
envelope provisions that do not contain
conditioned space.
Impact of the Differences Between the
2009 IRC and 2009 IECC
The Department of Energy has
performed a limited analysis of
potential impact of the differences
between the 2009 IECC and 2009 IRC.
The analysis involves thermal
simulation of home performance in
several representative locations using
the EnergyGauge (DOE–2) 9 simulation
tool on a typical house:
• 2400 ft2 floor area, two-story
• Natural gas furnace heating at
$1.20/therm
• Central air conditioning electricity
at 12 cents/kWh
• Equipment efficiencies at Federal
minimum levels
• 360 ft2 window area equally
distributed to the north, east, south, and
west building faces, with no exterior
shading.
The results are shown in Tables 8
through 10. The 2009 IRC yields a
higher annual energy cost in almost all
cases.
TABLE 8—ENERGY SAVINGS OF REDUCING SHGC FROM 0.35 TO 0.30 IN CLIMATE ZONES ONE THROUGH THREE
Climate zone
1
2
2
3
3
3
3
3
3
Cooling
savings
Representative city
............................................................
............................................................
............................................................
............................................................
............................................................
............................................................
............................................................
............................................................
............................................................
Miami ....................................................................................
Houston ................................................................................
Phoenix .................................................................................
Atlanta ..................................................................................
Jackson MS ..........................................................................
Memphis ...............................................................................
Dallas ....................................................................................
El Paso .................................................................................
Las Vegas ............................................................................
$29
18
20
16
19
17
20
18
16
Heating
increase
$0
9
1
18
15
17
14
17
15
Energy
savings
$29
9
19
¥2
4
0
6
1
1
TABLE 9—ENERGY SAVINGS OF INCREASING BASEMENT WALL INSULATION FROM R–13 TO R–19 IN CLIMATE ZONES SIX
THROUGH EIGHT
Energy
savings
Representative city
6 ................................................................................
7 ................................................................................
8 ................................................................................
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Climate zone
Burlington ..........................................................................................................
Duluth ................................................................................................................
Fairbanks ..........................................................................................................
9 EnergyGauge
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Federal Register / Vol. 75, No. 171 / Friday, September 3, 2010 / Notices
54141
TABLE 10—ENERGY SAVINGS OF INCREASING FLOOR INSULATION FROM R–30 TO R–38 IN CLIMATE ZONES SEVEN AND
EIGHT
[Floor over unheated basement]
Energy
savings
Climate zone
Representative city
7 ................................................................................
8 ................................................................................
Duluth ................................................................................................................
Fairbanks ..........................................................................................................
srobinson on DSKHWCL6B1PROD with NOTICES
IV. Filing Certification Statements With
DOE
A. State Determinations
If today’s determinations are
finalized, each State would be required
to determine the appropriateness of
revising the portion of its residential
building code regarding energy
efficiency to meet or exceed the
provisions of the ICC International
Energy Conservation Code, 2009
edition. (42 U.S.C. 6833(a)(5)(B)) A State
determination for the 2009 IECC would
be sufficient to address all of the DOE
determinations in this notice. Note that
the applicability of any State revisions
to new or existing buildings would be
governed by the State building codes.
However, it is our understanding that
generally, the revisions would not apply
to existing buildings unless they are
undergoing a change that requires a
building permit. The determinations
would be required to be made not later
than two years from the date of notice
final determination, unless an extension
is provided. The State determination
must be: (1) Made after public notice
and hearing; (2) in writing; (3) based
upon findings and upon the evidence
presented at the hearing; and (4) made
available to the public. States have
considerable discretion with regard to
the hearing procedures they use, subject
to providing an adequate opportunity
for members of the public to be heard
and to present relevant information. The
Department recommends publication of
any notice of public hearing in a
newspaper of general circulation.
Section 304(a)(4) of ECPA, as
amended, requires that if a State makes
a determination that it is not
appropriate to revise the energy
efficiency provisions of its residential
building code, the State must submit to
the Secretary, in writing, the reasons for
this determination and the statement
shall be available to the public. (42
U.S.C. 6833(a)(4))
States should be aware that the
Department considers high-rise (greater
than three stories) multifamily
residential buildings and hotel, motel,
and other transient residential building
types of any height as commercial
buildings for energy code purposes.
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Residential buildings include one- and
two-family detached and attached
buildings, duplexes, townhouses, row
houses, and low-rise multifamily
buildings (not greater than three stories)
such as condominiums and garden
apartments.
States should also be aware that the
determinations do not apply to Chapter
5 of the 2009 IECC, which addresses
commercial buildings as defined above.
Therefore, States must certify their
evaluations of their State building codes
for residential buildings with respect to
all provisions of the IECC except for
those chapters.
B. Requests for Extensions To Certify
Section 304(c) of ECPA, as amended,
requires that the Secretary permit an
extension of the deadline for complying
with the certification requirements
described above, if a State can
demonstrate that it has made a good
faith effort to comply with such
requirements and that it has made
significant progress toward meeting its
certification obligations. (42 U.S.C.
6833(c)) Such demonstrations could
include one or more of the following: (1)
A plan for response to the requirements
stated in Section 304, or (2) a statement
that the State has appropriated or
requested funds (within State funding
procedures) to implement a plan that
would respond to the requirements of
Section 304 of ECPA.
V. Regulatory Analysis
A. Review Under Executive Order 12866
Today’s action is a significant
regulatory action under section 3(f)(1) of
Executive Order 12866, ‘‘Regulatory
Planning and Review’’ (58 FR 51735;
October 4, 1993). Accordingly, today’s
action was reviewed by the Office of
Information and Regulatory Affairs
(OIRA) in the Office of Management and
Budget (OMB).
B. Review Under the Regulatory
Flexibility Act
The Regulatory Flexibility Act (5
U.S.C. 601 et seq.) requires the
preparation of an initial regulatory
flexibility analysis for any rule that by
law must be proposed for public
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19
comment, unless the agency certifies
that the rule, if promulgated, will not
have a significant economic impact on
a substantial number of small entities.
As required by Executive Order 13272,
‘‘Proper Consideration of Small Entities
in Agency Rulemaking,’’ (67 FR 53461;
August 16, 2002), DOE published
procedures and policies on February 19,
2003, to ensure that the potential
impacts of its rules on small entities are
properly considered during the
rulemaking process (68 FR 7990). DOE
has made its procedures and policies
available on the Office of General
Counsel’s Web site: https://
www.gc.doe.gov. Today’s action on the
determination of improved energy
efficiency between IECC editions would
require States to undertake an analysis
of their respective building codes.
Today’s action does not impact small
entities. Therefore, we certify that there
is no significant economic impact on a
substantial number of small entities.
C. Review Under the National
Environmental Policy Act of 1969
DOE has preliminarily determined
that today’s action is covered under the
Categorical Exclusion found in DOE’s
National Environmental Policy Act
regulations at paragraph A.6. of
Appendix A to subpart D, 10 CFR part
1021. That Categorical Exclusion
applies to actions that are strictly
procedural, such as rulemaking
establishing the administration of
grants. Today’s action impacts whether
States must perform an evaluation of
State building codes. The action would
not have direct environmental impacts.
Accordingly, DOE has not prepared an
environmental assessment or an
environmental impact statement.
D. Review Under Executive Order
13132, ‘‘Federalism’’
Executive Order 13132, 64 FR 43255
(August 4, 1999), imposes certain
requirements on agencies formulating
and implementing policies or
regulations that preempt State law or
that have federalism implications.
Agencies are required to examine the
constitutional and statutory authority
supporting any action that would limit
the policymaking discretion of the
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States and carefully assess the necessity
for such actions. DOE has examined
today’s action and has determined that
it will not preempt State law and will
not have a substantial direct effect on
the States, on the relationship between
the national government and the States,
or on the distribution of power and
responsibilities among the various
levels of government. Today’s action
impacts whether States must perform an
evaluation of State building codes. No
further action is required by Executive
Order 13132.
srobinson on DSKHWCL6B1PROD with NOTICES
E. Review Under the Unfunded
Mandates Reform Act of 1995
The Unfunded Mandates Reform Act
of 1995 (Pub. L. 104–4) generally
requires Federal agencies to examine
closely the impacts of regulatory actions
on State, local, and tribal governments.
Subsection 101(5) of Title I of that law
defines a Federal intergovernmental
mandate to include any regulation that
would impose upon State, local, or
tribal governments an enforceable duty,
except a condition of Federal assistance
or a duty arising from participating in a
voluntary Federal program. Title II of
that law requires each Federal agency to
assess the effects of Federal regulatory
actions on State, local, and tribal
governments, in the aggregate, or to the
private sector, other than to the extent
such actions merely incorporate
requirements specifically set forth in a
statute. Section 202 of that title requires
a Federal agency to perform a detailed
assessment of the anticipated costs and
benefits of any rule that includes a
Federal mandate which may result in
costs to State, local, or tribal
governments, or to the private sector, of
$100 million or more. Section 204 of
that title requires each agency that
proposes a rule containing a significant
Federal intergovernmental mandate to
develop an effective process for
obtaining meaningful and timely input
from elected officers of State, local, and
tribal governments.
Today’s action impacts whether States
must perform an evaluation of State
building codes. Today’s action would
not impose a Federal mandate on State,
local or tribal governments, and it
would not result in the expenditure by
State, local, and tribal governments in
the aggregate, or by the private sector, of
$100 million or more in any one year.
Accordingly, no assessment or analysis
is required under the Unfunded
Mandates Reform Act of 1995.
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F. Review Under the Treasury and
General Government Appropriations
Act of 1999
therefore not a significant energy action.
Accordingly, DOE has not prepared a
Statement of Energy Effects.
Section 654 of the Treasury and
General Government Appropriations
Act of 1999 (Pub. L. 105–277) requires
Federal agencies to issue a Family
Policymaking Assessment for any rule
that may affect family well-being.
Today’s action would not have any
impact on the autonomy or integrity of
the family as an institution.
Accordingly, DOE has concluded that it
is not necessary to prepare a Family
Policymaking Assessment.
I. Review Under Executive Order 13175
G. Review Under the Treasury and
General Government Appropriations
Act of 2001
Section 515 of the Treasury and
General Government Appropriations
Act, 2001 (44 U.S.C. 3516, note)
provides for agencies to review most
disseminations of information to the
public under guidelines established by
each agency pursuant to general
guidelines issued by OMB. OMB’s
guidelines were published at 67 FR
8452 (February 22, 2002), and DOE’s
guidelines were published at 67 FR
62446 (October 7, 2002). DOE has
reviewed today’s action under the OMB
and DOE guidelines and has concluded
that it is consistent with applicable
policies in those guidelines.
H. Review Under Executive Order 13211
Executive Order 13211, ’’Actions
Concerning Regulations That
Significantly Affect Energy Supply,
Distribution, or Use,’’ 66 FR 28355 (May
22, 2001), requires Federal agencies to
prepare and submit to the OMB a
Statement of Energy Effects for any
proposed significant energy action. A
‘‘significant energy action’’ is defined as
any action by an agency that
promulgated or is expected to lead to
promulgation of a final rule, and that:
(1) Is a significant regulatory action
under Executive Order 12866, or any
successor order; and (2) is likely to have
a significant adverse effect on the
supply, distribution, or use of energy, or
(3) is designated by the Administrator of
the Office of Information and Regulatory
Affairs (OIRA) as a significant energy
action. For any proposed significant
energy action, the agency must give a
detailed statement of any adverse effects
on energy supply, distribution, or use,
should the proposal be implemented,
and of reasonable alternatives to the
action and their expected benefits on
energy supply, distribution, and use.
Today’s action would not have a
significant adverse effect on the supply,
distribution, or use of energy and is
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Executive Order 13175. ‘‘Consultation
and Coordination with Indian tribal
Governments’’ (65 FR 67249; November
9, 2000), requires DOE to develop an
accountable process to ensure
‘‘meaningful and timely input by tribal
officials in the development of
regulatory policies that have tribal
implications.’’ ‘‘Policies that have tribal
implications’’ refers to regulations that
have ‘‘substantial direct effects on one or
more Indian tribes, on the relationship
between the Federal Government and
Indian tribes, or on the distribution of
power and responsibilities between the
Federal Government and Indian tribes.’’
Today’s regulatory action is not a policy
that has ‘‘tribal implications’’ under
Executive Order 13175. DOE has
reviewed today’s action under Executive
Order 13175 and has determined that it
is consistent with applicable policies of
that Executive Order.
VI. Public Participation
The public is invited to submit
comments on the preliminary
determinations. Comments must be
provided by October 4, 2010 using any
of the methods described in the
ADDRESSES section of this notice. If you
submit information that you believe to
be exempt by law from public
disclosure, you should submit one
complete copy, as well as one copy from
which the information claimed to be
exempt by law from public disclosure
has been deleted. DOE is responsible for
the final determination with regard to
disclosure or nondisclosure of the
information and for treating it
accordingly under the DOE Freedom of
Information regulations at 10 CFR
1004.11.
VII. Approval of the Office of the
Secretary
The Secretary of Energy has approved
publication of these preliminary
determinations.
Issued in Washington, DC, on August 26,
2010.
Cathy Zoi,
Assistant Secretary, Energy Efficiency and
Renewable Energy.
[FR Doc. 2010–22062 Filed 9–2–10; 8:45 am]
BILLING CODE 6450–01–P
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[Federal Register Volume 75, Number 171 (Friday, September 3, 2010)]
[Notices]
[Pages 54131-54142]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-22062]
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DEPARTMENT OF ENERGY
[Docket No. EERE-2010-BT-DET-0030]
RIN 1904-AC17
Updating State Residential Building Energy Efficiency Codes
AGENCY: Office of Energy Efficiency and Renewable Energy, Department of
Energy.
ACTION: Notice of proposed determination.
-----------------------------------------------------------------------
SUMMARY: The Department of Energy (DOE or Department) has preliminarily
determined that the 2009 version of the International Code Council
(ICC) International Energy Conservation Code (IECC) would achieve
greater energy efficiency in low-rise residential buildings than the
2006 IECC. Also, DOE has preliminarily determined that the 2006 version
of the IECC would achieve greater energy efficiency than the 2003 IECC.
Finally, DOE has preliminarily determined that the 2003 version of the
IECC would not achieve greater energy efficiency than the 2000 IECC. If
these determinations are finalized, States would be required to file
certification statements to DOE that they have reviewed the provisions
of their residential building code regarding energy efficiency and made
a determination as to whether to update their code to meet or exceed
the most recent code with an affirmative determination, the 2009 IECC.
Additionally, this Notice provides guidance to States on how the codes
have changed from previous versions, how to submit certifications, and
how to request extensions of the deadline to submit certifications,
should the preliminary determinations be adopted as final.
DATES: Comments on the preliminary determinations must be provided by
October 4, 2010.
ADDRESSES: You may submit comments, identified by any of the following
methods:
Federal eRulemaking Portal: https://www.regulations.gov.
Follow the instructions for submitting comments.
E-mail: ronald.majette@ee.doe.gov. Include RIN 1904-AC17
in the subject line of the message.
Postal Mail: Mr. Ronald B. Majette, U.S. Department of
Energy, Office of Energy Efficiency and Renewable Energy, Forrestal
Building, Mail Station EE-2J, 1000 Independence Avenue, SW.,
Washington, DC 20585-0121. Please submit one signed paper original.
Hand Delivery/Courier: Mr. Ronald B. Majette, U.S.
Department of Energy, Federal Energy Management Program, Room 6003,
1000 Independence Avenue, SW., Washington, DC 20585-0121.
Instructions: All submissions must include the agency name,
Department of Energy, and docket number, EERE-2010-BT-DET-0030, or
Regulatory Information Number (RIN), 1904-AC17, for this rulemaking.
FOR FURTHER INFORMATION CONTACT: Mr. Ronald B. Majette, U.S. Department
of Energy, Office of Energy Efficiency and Renewable Energy, Forrestal
Building, Mail Station EE-2J, 1000 Independence Avenue, SW.,
Washington, DC 20585-0121, 202-586-7935. For legal issues contact Chris
Calamita, U.S. Department of Energy, Office of the General Counsel,
Forrestal Building, GC-72, 1000 Independence Avenue, SW., Washington,
DC 20585, (202) 586-9507, e-mail: Christopher.Calamita@hq.doe.gov.
SUPPLEMENTARY INFORMATION:
I. Introduction
A. Statutory Requirements
B. Background
C. DOE's Preliminary Determination Statements
II. Discussion of Changes in the 2003, 2006, and 2009 IECC
A. 2003 IECC Compared With the 2000 IECC
B. 2006 IECC Compared With the 2003 IECC
C. 2009 IECC Compared With the 2006 IECC
III. Comparison of the 2009 IRC to the 2009 IECC
IV. Filing Certification Statements With DOE
A. State Determinations
B. Certification
C. Request for Extensions
V. Regulatory Analysis
A. Review Under Executive Order 12866
B. Review Under the Regulatory Flexibility Act
C. Review Under the National Environmental Policy Act of 1969
D. Review Under Executive Order 13132, ``Federalism''
E. Review Under the Unfunded Mandates Reform Act of 1995
F. Review Under the Treasury and General Government
Appropriations Act of 1999
G. Review Under the Treasury and General Government
Appropriations Act of 2001
H. Review Under Executive Order 13211
I. Review Under Executive Order 13175
VI. Public Participation
VII. Approval of the Office of the Secretary
I. Introduction
A. Statutory Requirements
Title III of the Energy Conservation and Production Act, as amended
(ECPA), establishes requirements for the Building Energy Standards
Program. (42 U.S.C. 6831-6837) Section 304(b) of ECPA, as amended,
provides that when the 1992 Model Energy Code, or any successor to that
code, is revised, the Secretary of the Department of Energy must
determine, not later than 12 months after the revision, whether the
revised code would improve energy efficiency in residential buildings
and must publish notice of the determination in the Federal Register.
(42 U.S.C. 6833(a)(5)(A)) The Department, following precedent set by
the International Code Council (ICC) and the American Society of
Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
considers high-rise (greater than three stories) multifamily
residential buildings and hotel, motel, and other transient residential
building types of any height as commercial buildings for energy code
purposes. Low-rise residential buildings include one- and two-family
detached and attached buildings, duplexes, townhouses, row houses, and
low-rise multifamily buildings (not greater than three stories) such as
condominiums and garden apartments.
If the Secretary determines that the revision would improve energy
efficiency then, not later than 2 years after the date of the
publication of the affirmative determination, each State is required to
certify that it has compared its residential building code regarding
energy efficiency to the revised code and made a determination whether
it is appropriate to revise its code to meet or exceed the provisions
of the successor code. (42 U.S.C. 6833(a)(5)(B)) State determinations
are to be made: (1) After public notice and hearing; (2) in writing;
(3) based upon findings included in such determination and upon
evidence presented at the hearing; and (4) available to the public.
(See, 42 U.S.C. 6833(a)(5)(C)) In addition, if a State determines that
it is not appropriate to revise its residential building code, the
State is required to submit to the Secretary, in writing, the reasons,
which
[[Page 54132]]
are to be made available to the public. (See, 42 U.S.C. 6833(a)(5)(C))
B. Background
The International Code Council's (ICC) International Energy
Conservation Code (IECC) establishes national energy efficiency
requirements for buildings. In 1997, the Council of American Building
Officials (CABO) was incorporated into the ICC and the Model Energy
Code (MEC) was renamed to the IECC. A previous Federal Register notice,
59 FR 36173, July 15, 1994, announced the Secretary's determination
that the 1993 MEC increased energy efficiency relative to the 1992 MEC
for residential buildings. Similarly, another Federal Register notice,
61 FR 64727, December 6, 1996, announced the Secretary's determination
that the 1995 MEC is an improvement over the 1993 MEC. Finally, Federal
Register notice 66 FR 1964, January 10, 2001, simultaneously announced
the Secretary's determination that the 1998 IECC is an improvement over
the 1995 MEC and the 2000 IECC is an improvement over the 1998 IECC.
C. DOE's Preliminary Determination Statement
2003 IECC
The Department of Energy's review and evaluation found that there
are not significant differences in energy efficiency between the 2003
edition and the 2000 edition of the IECC. Although there are a few
changes that would modestly improve the energy efficiency of
residential buildings, there are a number of changes that reduce energy
efficiency in certain situations. Most of the changes to the IECC
between the 2000 and 2003 editions would not affect energy efficiency
but rather make the code simpler and clearer for designers, builders,
and code compliance officials to understand and use. Based on these
findings, the Department has preliminarily concluded that the 2003
edition of the IECC should not receive an affirmative determination
under Section 304(b) of ECPA. The Department preliminarily concludes
that there is a slight improvement in energy efficiency for many
residential buildings, but this improvement is not sufficient to merit
an affirmative determination. It should be noted that DOE is not
concluding that the energy efficiency of the 2003 IECC less stringent
than the 2000 IECC.
2006 IECC
The residential portion of the 2006 IECC has been extensively
changed from that the 2003 IECC. However, the most significant changes
to the code between 2003 and 2006 simplify the code format rather than
fundamentally changing the overall (national average) energy efficiency
of the code. Multifamily buildings, which in the past have had
separate, less stringent thermal requirements, are an exception. By
eliminating the separate requirements, the 2006 IECC increased the
energy efficiency of multifamily buildings.
Although the most significant 2006 changes did not directly target
efficiency improvements, the new format of the code does result in some
energy efficiency differences. The requirements for any given building
may have increased or decreased based on the specific location
(climate) and building design. The Department has preliminarily found
that overall the 2006 IECC has a small improvement in energy efficiency
compared to the 2003 IECC. The Department preliminarily concludes that
the 2006 edition of the IECC should receive an affirmative
determination under Section 304(b) of EPCA.
2009 IECC
The 2009 IECC has substantial revisions compared to the 2006 IECC.
Many of these revisions appear to directly improve energy efficiency,
and the sum results of all changes appear to result in a significant
increase in code stringency. Therefore, the Department preliminarily
concludes that the 2009 edition of the IECC should receive an
affirmative determination under Section 304(b) of EPCA.
II. Discussion of Changes in the 2003, 2006, and 2009 IECC
A. 2003 IECC Compared With the 2000 IECC
As a whole, the 2003 IECC's provisions for energy efficiency in
residential buildings appear largely unchanged from the 2000 IECC.
There are some changes in the code that can have a modest effect on
energy efficiency. These are discussed below. In addition, there is a
variety of minor changes intended to make the code more concise, more
complete, and better organized, but not more or less stringent. For
example, more specific requirements have been added for steel roofs/
ceilings and floors to correspond to those already in the code for
steel walls. Another example is the relocation of the 51 pages of state
maps from the middle of the code to the back of the code. Additionally,
the performance path in Chapter 4 of the 2003 IECC contains a variety
of modest improvements compared to the 2000 IECC, which creates more
concise requirements.
Changes in the 2003 IECC That Improve Energy Efficiency
1. Increased Duct Insulation Requirements
Duct insulation requirements generally increased in the 2003 IECC.
The 2003 IECC requirements are shown in Table 1. These are somewhat
difficult to compare to the 2000 IECC requirements because the latter
are more complex, differing between ducts in unconditioned spaces and
ducts completely exterior to the building and distinguishing
requirements by the design temperature difference between the duct air
and the space in which the ducts are located. The 2000 IECC
requirements for ducts in unconditioned spaces are shown in Table 2.
Assuming typical supply air temperatures of 55 degrees F for cooling
and 95 degrees F for heating (for heat pumps), the 2000 IECC insulation
requirement for supply ducts in unconditioned spaces is R-5 (minimum)
for nearly all cases. Insulation required by the 2000 IECC for return
ducts in unconditioned spaces will generally be R-3.3 in warmer
climates and R-5 in colder climates.
For the very common case of supply ducts in attics, and the case
that is likely to have the greatest impact on energy use, the 2003 IECC
always requires at least R-8, which exceeds the 2000 IECC's R-5
requirement. For supply ducts in other unconditioned spaces, the 2003
IECC's requirements exceed the 2000 IECC's requirements in all cases
except very warm locations (less than 1500 heating degree-days), where
the 2003 IECC requires R-4 compared to the 2000 IECC's requirement of
R-5. Because supply ducts transport air in its hottest (or coldest)
condition, insulation has its greatest impact on these ducts. The 2003
IECC is almost always more stringent than the 2000 IECC for supply
ducts. This includes all supply ducts in attics and, based on the
distribution of population \1\, more than 80% of ducts in other
unconditioned spaces.
---------------------------------------------------------------------------
\1\ Estimated from USGS Population Places data that allows
mapping of population to climate (https://geonames.usgs.gov/domestic/download_data.htm).
---------------------------------------------------------------------------
Requirements for return ducts in attics are slightly more stringent
in the 2003 IECC (R-4 vs R-3.3) in the warmest climates, slightly less
stringent (R-4 vs R-5) in mid climates, and slightly more stringent (R-
6 vs R-5) in the coldest climates.
[[Page 54133]]
Research \2\ showing the impact on heating and cooling energy use
due to duct insulation is summarized in Table 3. Based on this
research, the Department estimates that improved duct insulation in the
2003 IECC will reduce heating and cooling energy use by about 1%.
---------------------------------------------------------------------------
\2\ Triedler, B., R. Lucas, M. Modera, J. Miller. 1996. Impact
of Residential Duct Insulation on HVAC Energy Use and Life-Cycle
Costs to Consumers. American Society of Heating, Refrigerating, and
Air-Conditioning Engineers.
Table 1--Duct Insulation Requirements in the 2003 IECC
----------------------------------------------------------------------------------------------------------------
Insulation R-value (h [middot] ft2 [middot] [deg]F)/Btu
-------------------------------------------------------------------------------
Ducts in unconditioned attics or Ducts in unconditioned basements,
Annual heating degree days base outside building crawl spaces, and other unconditioned
65[deg]F ---------------------------------------- spaces
---------------------------------------
Supply Return Supply Return
----------------------------------------------------------------------------------------------------------------
Below 1,500..................... 8 4 4 0
1,500 to 3,500.................. 8 4 6 2
3,501 to 7,500.................. 8 4 8 2
Above 7,500..................... 11 6 11 2
----------------------------------------------------------------------------------------------------------------
Table 2--Insulation Requirements (R-value, h-ft2-F/Btu) for Ducts in
Unconditioned Spaces in the 2000 IECC
------------------------------------------------------------------------
Design Temperature Difference
(TD) between air temperature in
duct and space in which duct is Cooling Heating
located (degrees F)
------------------------------------------------------------------------
TD <= 15........................ None required..... None required.
40 >= TD > 15................... 3.3............... 3.3.
TD > 40......................... 5.0............... 5.0.
------------------------------------------------------------------------
Table 3--Heating and Cooling Energy Savings (Percent) From Increased Duct Insulation
[Atlanta, Natural Gas Heating]
----------------------------------------------------------------------------------------------------------------
Attic Basement Crawlspace
----------------------------------------------------------------------------------------------------------------
R-4 to R-6...................................................... 2.3 1.6 1.8
R-6 to R-8...................................................... 1.4 0.9 1.1
----------------------------------------------------------------------------------------------------------------
2. Minor Changes to ``Systems Analysis'' Performance Compliance Method
There are two changes that can increase the stringency of the
performance path in Chapter 4 of the 2003 IECC in certain cases. First,
any house proposed to use electric resistance heating must have equal
or lower calculated energy use than a hypothetical ``standard design''
that uses a more efficient electric air source heat pump. This change
makes the performance approach much more stringent for designs that
have electric resistance heating. However, compliance can be achieved
for these designs using the prescriptive compliance methods in Chapters
5 and 6, thereby bypassing the increased stringency of the performance
path.
Second, a provision has also been added requiring that the least
efficient orientation in terms of energy use be assumed for a proposed
group of residences with identical designs. Therefore, in a development
where the same design is built on multiple lots facing various
directions, the compliance analysis must be based on the least
advantageous orientation. In most of the United States, this is the
orientation that points the most window area toward a westerly
direction, maximizing solar heat gains in summer afternoons and
therefore increasing air conditioning energy use. Because proposed
building designs must have a calculated annual energy use equal to or
less than that of a home with window area equally distributed toward
the four cardinal directions, the requirement to assume the least
efficient orientation effectively makes the code more stringent because
the increased energy use from the least efficient orientation must be
offset by improved energy efficiency. This requirement in the 2003 IECC
will have only modest average impact because it affects only the
performance approach and identical house designs used repeatedly in a
development.
B. Changes in the 2003 IECC That Decrease Energy Efficiency
1. Sunroom Additions
A special set of requirements has been added to Table 502.2.5 of
the 2003 IECC for sunroom additions having a floor area of less than
500 ft\2\ (46.5 m\2\). Sunroom additions are permitted to have ceiling,
wall insulation, and window U-factor requirements that are typically
less stringent than the requirements for all other types of residential
construction. These special requirements for sunrooms only apply to
additions to existing dwellings, not to sunrooms that are built as part
of a new dwelling. In the 2000 IECC, there were no special requirements
for sunroom additions; they had to meet the same requirements as other
residential construction. To qualify for the less stringent
requirements in the 2003 IECC, the sunroom addition must be capable of
being controlled as a separately heated and cooled zone. Additionally,
new walls, doors or windows between the sunroom and the house must meet
the envelope requirements of the IECC. Finally, the glazing area must
exceed 40% of the gross area of the exterior walls and roof to qualify
as a sunroom in the IECC.
Testing with the DOE-2 simulation tool indicates that for a 500
ft\2\ sunroom, the less stringent 2003 requirements could add about
$200 to the annual energy costs in Chicago if the sunroom is both
heated and cooled all year. Impacts are much smaller in Houston,
[[Page 54134]]
about $10 added energy costs. However, this increase in energy
consumption is mitigated (on average) by several factors. First, the
requirements apply to a very small fraction of all new residential
construction. The Wall Street Journal Online (June 3, 2003) reports
three billion dollars worth of sunroom construction each year, or less
than one percent of all residential construction expenditures. But that
fraction includes new construction as well as additions, so the
fraction representing sunroom additions is less than 1%. Second, it is
expected that many sunrooms will not be maintained at comfort
conditions all year, further reducing the overall impact. Finally,
because the 2003 IECC requires that the sunroom be thermally isolated
from the rest of the house and that walls, windows, and doors between
the sunroom and house meet the code's envelope requirements, the
thermal impact when these spaces are not actively conditioned is
negligible. Therefore, the overall impact of this reduction in
stringency to national energy use is expected to be extremely small.
2. Climate Zone Maps
The IECC contains prescriptive envelope requirements (insulation R-
values and glazing U-factors) in Chapter 6 and Section 502.2.4 of the
code. In the 2000 IECC, only the heating degree-days for the city where
the housing was to be built could be used to determine the applicable
prescriptive envelope requirements. In the 2003 IECC, the heating
degree-days can still be used to determine the requirements, but
additionally the designer/builder can use the climate zones provided in
the state maps in the IECC. For most locations, the Chapter 3 climate
zones and heating degree-days lead to the exact same requirements.
Using the climate zones in the maps instead of the heating degree-days
will allow about 10% of cities nationwide to have a less stringent set
of prescriptive requirements. However, about 20% of cities nationwide
will have more stringent requirements when the climate zones are used
with the prescriptive requirements. If the designer/builders select to
use the climate zone maps in the 10% of cities where it lowers
requirements but not in the 20% of locations where it raises
requirements, the 2003 code effectively is less stringent. However, DOE
believes code users will make use of the climate zone maps even in many
of the locations where they raise requirements. It is doubtful most
code users will go through the level of effort of determining which
method of determining climate based requirements may give less
stringent requirements. In fact, DOE believes most users will not even
be aware of these differences, but will prefer the climate zone maps
because of their simplicity. The REScheck compliance materials
developed by the U.S. Department of Energy utilize the same heating
degree day based requirements for both the 2000 and 2003 IECC.
3. Increased U-Factor for Skylight Replacements
The maximum U-factor for skylight replacements in existing
buildings (Section 502.2.5 of the IECC) is raised from a U-factor of
0.50 to a U-factor of 0.60 for locations above 1,999 heating degree-
days. A higher U-factor reduces energy efficiency.
C. Net Impact on Energy Efficiency
The change in the 2003 IECC that is expected to have the greatest
impact on energy efficiency for the nation is the improved duct
insulation because a majority of new residential buildings have ducts
that pass through attics, crawl spaces, unheated basements and other
spaces where the IECC requires duct insulation. The improved duct
insulation in the 2003 IECC is estimated to save about 1% of heating
and cooling costs.
The ``Systems Analysis'' performance compliance method is a less
commonly used compliance method and the modest energy savings from the
improvements in this optional compliance method can easily be bypassed
by choosing a different compliance method. Because this approach is
optional, it is impossible to calculate the cumulative effect these
code changes will have on energy efficiency. DOE believes that the
changes to the system analysis method are insufficient to sway the
decision on whether the determination is affirmative or not.
The changes that reduce energy efficiency for sunroom additions and
skylight replacements are not considered to have substantial impacts on
national energy use as they do not apply to new buildings and only
apply to specific types or retrofits and additions to existing
buildings. The skylight U-factor change is only a modest reduction in
energy efficiency and sunroom additions are a small fraction of the
residential construction market.
The addition of the climate zone maps in the 2003 IECC as an option
to using city-specific heating degree-day data allows for the
possibility of preferentially lowering thermal envelope requirements in
about 10% of all national locations. However, it is difficult to
exploit this change because the code user must perform relatively
complex calculations rather than using the popular and user-friendly
REScheck software.
DOE preliminarily concludes the improved duct insulation will
slightly improve energy efficiency in most houses. However, the
reductions in energy efficiency for skylight replacements and sunroom
additions are expected to at least partially offset these savings from
a national energy total use perspective. The vast majority of all
requirements in the IECC are unchanged from 2000 to 2003. For these
reasons, DOE initially finds insufficient improvements in the 2003 to
merit an affirmative determination.
B. 2006 IECC Compared With the 2003 IECC
The residential portion of the IECC in general and the building
thermal envelope (ceilings, walls, doors, windows, foundations, etc.)
requirements in particular were completely restructured from 2003 to
2006. This resulted in the code becoming much shorter and simpler, its
volume reduced from 38 pages to 9 pages. The climate basis on which
envelope requirements depend was completely reworked. The 2003 IECC has
envelope requirements that vary continuously with heating degree-days
(HDD),\3\ or with 17 HDD zones (geographically-defined based on
counties, roughly following 500-HDD bins). In contrast, the 2006 IECC
has eight geographically-defined climate zones with all borders set on
county boundaries.
---------------------------------------------------------------------------
\3\ Some compliance paths defined requirements based on 17
``zones'' based on HDD ranges.
---------------------------------------------------------------------------
A major change to envelope requirements was the combining of
separate requirements for two building categories (one- and two-family
dwellings, and all other low-rise residential buildings). The 2006 IECC
requirements are the same for all low-rise residential building types,
which has the effect of increasing the energy efficiency of the other
low-rise buildings. Also eliminated were nine related tables that
provided predefined packages of thermal transmittance prescriptive
requirements (glazing, ceiling-roof, exterior wall, floor over
unconditioned space, basement and crawl space walls, and floor slab on
grade) for different window to wall area ratios (WWR). In their place,
the 2006 IECC provides a single table of predefined packages of thermal
[[Page 54135]]
transmittance prescriptive requirements that do not vary with WWR.
Table 4 shows a comparison of major prescriptive envelope
requirements for a single-family house at a typical 15% WWR. The
requirements for the 2003 IECC will differ from those shown in Table 4
for other WWRs and for multifamily buildings. The 2006 IECC climate
zones do not exactly map to the 2003 IECC zones. Table 5 shows a more
detailed estimate of how residential construction maps from the 2006
IECC compare to the 2003 IECC climate zones.
Table 4--Comparison of the 2003 IECC and 2006 IECC Envelope Thermal Component Prescriptive Criteria for One- and Two-Family Dwellings at 15% Window Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
IECC climate zone Maximum Minimum
------------------------------ ------------------------------------------------------------------------------------------------------
Heating degree Glazing U-factor Ceiling R-value Wall R-value Floor R-value
days ------------------------------------------------------------------------------------
2003 2006 ------------------
2003 2006 2003 2006 2003 2006 2003 2006
--------------------------------------------------------------------------------------------------------------------------------------------------------
1........... 1 2 0-499............. Any 1.20 R-13 R-30 R-11 R-13 R-11 R-13
--------------------------------------------------------------------------------------------------------------------------------------------------------
2........... .............. 500-999........... 0.90 0.75 R-19 R-30 R-11 R-13 R-11 R-13
��������������
3........... 2 1,000-1,499....... 0.75 0.75 R-19 R-30 R-11 R-13 R-11 R-13
��������������
4........... .............. 1,500-1,999....... 0.75 0.75 R-26 R-30 R-13 R-13 R-11 R-13
--------------------------------------------------------------------------------------------------------------------------------------------------------
5........... .............. 2,000-2,499....... 0.65 0.65 R-30 R-30 R-13 R-13 R-11 R-19
��������������
6........... 3 2,500-2,999....... 0.60 0.65 R-30 R-30 R-13 R-13 R-19 R-19
��������������
7........... .............. 3,000-3,499....... 0.55 0.65 R-30 R-30 R-13 R-13 R-19 R-19
--------------------------------------------------------------------------------------------------------------------------------------------------------
8........... .............. 3,500-3,999....... 0.50 0.40 R-30 R-38 R-13 R-13 R-19 R-19
��������������
9........... 4 4,000-4,499....... 0.45 0.40 R-38 R-38 R-13 R-13 R-19 R-19
��������������
10........... .............. 4,500-4,999....... 0.45 0.40 R-38 R-38 R-16 R-13 R-19 R-19
--------------------------------------------------------------------------------------------------------------------------------------------------------
11........... .............. 5,000-5,499....... 0.45 0.35 R-38 R-38 R-18 R-19 R-19 R-19/30
��������������
12........... .............. 5,500-5,999....... 0.40 0.35 R-38 R-38 R-18 R-19 R-21 R-19/30
��������������
13........... 5 6,000-6,499....... 0.35 0.35 R-38 R-38 R-18 R-19 R-21 R-19/30
��������������
14........... .............. 6,500--6,999...... 0.35 0.35 R-49 R-38 R-21 R-19 R-21 R-19/30
--------------------------------------------------------------------------------------------------------------------------------------------------------
15........... 5 6 7,000-8,499....... 0.35 0.35 R-49 R-38/49 R-21 R-19 R-21 R-21
--------------------------------------------------------------------------------------------------------------------------------------------------------
16........... 6 8,500-8,999....... 0.35 0.35 R-49 R-49 R-21 R-21 R-21 R-21
--------------------------------------------------------------------------------------------------------------------------------------------------------
17........... 7 9,000-12,999...... 0.35 0.35 R-49 R-49 R-21 R-21 R-21 R-21
--------------------------------------------------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
IECC climate zone Minimum
--------------------------- -------------------------------------------------------------------
Heating degree Basement wall Slab perimeter R-value Crawl space wall R-value
days R-value and depth feet
2003 2006 -------------------------------------------------------------------
2003 2006 2003 2006 2003 2006
----------------------------------------------------------------------------------------------------------------
1.......... 1 2 0-499........... R-0 R-0 R-0 R-0 R-0 R-0
----------------------------------------------------------------------------------------------------------------
2.......... ............ 500-999......... R-0 R-0 R-0 R-0 R-4 R-0
�������������
3.......... 2 1,000-1,499..... R-0 R-0 R-0 R-0 R-5 R-0
�������������
4.......... ............ 1,500-1,999..... R-5 R-0 R-0 R-0 R-5 R-0
----------------------------------------------------------------------------------------------------------------
5.......... ............ 2,000-2,499..... R-5 R-10/ R-0 R-0 R-6 R-5
13
�������������
6.......... 3 2,500-2,999..... R-6 R-10/ R-4,2 R-0 R-7 R-5
13
�������������
7.......... ............ 3,000-3,499..... R-7 R-10/ R-4,2 R-0 R-8 R-5
13
----------------------------------------------------------------------------------------------------------------
[[Page 54136]]
8.......... ............ 3,500-3,999..... R-8 R-10/ R-5,2 R-10,2 R-10 R-10
13
�������������
9.......... 4 4,000-4,499..... R-8 R-10/ R-5,2 R-10,2 R-11 R-10
13
�������������
10.......... ............ 4,500-4,999..... R-9 R-10/ R-6,2 R-10,2 R-17 R-10
13
----------------------------------------------------------------------------------------------------------------
11.......... ............ 5,000-5,499..... R-9 R-10/ R-6,2 R-10,2 R-17 R-10
13
�������������
12.......... ............ 5,500-5,999..... R-10 R-10/ R-9,4 R-10,2 R-19 R-10
13
�������������
13.......... 5 6,000-6,499..... R-10 R-10/ R-9,4 R-10,2 R-20 R-10
13
�������������
14.......... ............ 6,500-6,999..... R-11 R-10/ R-11,4 R-10,2 R-20 R-10
13
----------------------------------------------------------------------------------------------------------------
15.......... 5 6 7,000-8,499..... R-11 R-10/ R-13,4 R-10,2 R-20 R-10
13
----------------------------------------------------------------------------------------------------------------
16.......... 6 8,500-8,999..... R-18 R-10/ R-14,4 R-10,4 R-20 R-10
13
----------------------------------------------------------------------------------------------------------------
17.......... 7 9,000-12,999.... R-19 R-10/ R-18 R-10,4 R-20 R-10
13
----------------------------------------------------------------------------------------------------------------
Table 5--Percentage of Homes in Each 2006 IECC Climate Zone That Would Have Been in Each 2003 IECC Climate Zone
--------------------------------------------------------------------------------------------------------------------------------------------------------
2006 IECC climate zone
------------------------------------------------------------------------------------------
2003 IECC climate zone 4 except 5 and
1 2 3 marine marine 4 6 7 & 8
--------------------------------------------------------------------------------------------------------------------------------------------------------
1............................................................ 100 5 0 0 0 0 0
2............................................................ 0 20 0 0 0 0 0
3............................................................ 0 40 22 0 0 0 0
4............................................................ 0 31 10 0 0 0 0
5............................................................ 0 3 18 0 0 0 0
6............................................................ 0 0 28 0 0 0 0
7............................................................ 0 0 16 4 0 0 0
8............................................................ 0 0 6 9 0 0 0
9............................................................ 0 0 0 13 1 0 0
10........................................................... 0 0 0 28 6 0 0
11........................................................... 0 0 0 41 8 0 0
12........................................................... 0 0 0 5 28 0 0
13........................................................... 0 0 0 0 31 0 0
14........................................................... 0 0 0 0 20 12 0
15........................................................... 0 0 0 0 6 81 3
16........................................................... 0 0 0 0 0 5 6
17........................................................... 0 0 0 0 0 2 85
18........................................................... 0 0 0 0 0 0 5
19........................................................... 0 0 0 0 0 0 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
The Department has conducted an analysis and has preliminarily
found that the 2006 IECC would modestly increase energy efficiency on
an overall national average basis. This analysis is summarized below; a
technical support document published in conjunction with this Notice
contains the full results. The Department stresses that this increased
energy efficiency is based on an average across all new residential
buildings. The analysis identified combinations of locations and
building design where the 2006 IECC would slightly reduce energy
efficiency; however, the analysis indicates that the reductions would
be more than offset by cases where energy efficiency is improved.
Table 6 provides the overall results of the comparative analysis of
the
[[Page 54137]]
prescriptive envelope requirements of the 2006 IECC and the 2003 IECC.
The DOE-2 energy simulation software was used to calculate these
values. The 2006 IECC has a 1% average overall national energy savings.
The table shows combined results for single-family and multifamily
construction accounting for weighted average building characteristics.
Table 6 illustrates significant regional differences that are primarily
a result of the revised climate zones. In most climates, the two codes
are very nearly equivalent. In climate zone 5, the 2006 IECC shows a
substantial improvement (about 5%). In climate zone 3, the 2003 IECC is
more energy efficient (by about 5%).
Table 6--Annual Energy Savings (MBtu) of 2006 IECC Compared to 2003 IECC for Prescriptive Building Envelope
Requirements
----------------------------------------------------------------------------------------------------------------
Foundation type
---------------------------------------------------- Percent
2006 IECC Climate zone Heated Slab-on- Unheated Average savings
basement Crawl space grade basement
----------------------------------------------------------------------------------------------------------------
Zone 1............................ 0.5 0.4 0.3 0.4 0.3 2
Zone 2............................ -0.1 1.4 0.9 -0.1 0.9 3
Zone 3............................ -8.6 -1 -3.3 -1.5 -3.4 -5
Zone 4............................ 2 0.8 0.6 0.7 1.1 1
Zone 5............................ 5.5 7.3 4.2 6.3 5.7 5
Zone 6............................ 1.1 3.3 0 2.3 1.4 1
Zone 7............................ -2 4.5 0.4 3.4 -0.4 0
Average........................... 2.4 2.7 -0.3 3.3 1 1
----------------------------------------------------------------------------------------------------------------
The analysis underlying the results in Table 6 does not account for
all changes in the IECC from 2003 to 2006. For example, the 2006 IECC
requires increased duct insulation in certain cases. On the other hand,
the 2006 IECC is missing requirements for pool heater controls (on-off
switch) and pool covers contained in the 2003 IECC. However, these and
a few other miscellaneous changes do not appear to alter a
determination that the 2006 IECC has a modest improvement in overall
energy efficiency compared to the 2003 IECC. The Department expects all
heated pools to have an on-off switch, basic pool covers are dependent
on the diligent occupant behavior for removing/covering the pool, and
many homes do not have a pool or may not heat their pool. Furthermore,
the 2003 IECC allows the pool cover requirement to be bypassed if 20%
of the heating energy is provided by solar heat from the sun striking
the pool surface.
There was one particular issue that received the most extensive
debate during the 2006 IECC development process. This issue was how the
2006 IECC sets requirements based on the window area of a home. There
was considerable concern because a residential building with unlimited
windows (e.g., an ``all glass'' house) can be built without any penalty
under the 2006 IECC. This is not the case in the 2003 IECC, where, as
the WWR becomes higher, the code requires improved performance of
windows and/or wall insulation. However, this effect is offset in two
ways. First, while the 2003 IECC becomes more stringent at high WWRs,
it also becomes less stringent at low WWRs, whereas the 2006 IECC does
not. Second, the 2006 IECC increased the baseline efficiency
requirements (U-factor) of glazing to almost equal then-current Energy
Star levels in most locations. The Department's analysis of the IECC's
requirements related to window area indicate that the 2006 code is not
weaker than the 2003 IECC when the distribution of window areas in all
residential buildings is accounted for.
A major factor influencing the Department's preliminary
determination of improved efficiency in the 2006 IECC is the
improvement in energy efficiency for multifamily housing. The building
envelope requirements in 2006 IECC are identical for all residential
building types. This is not the case in the 2003 IECC where the
requirements for multifamily building types are considerably less
stringent than those for one and two-family dwellings. This is shown in
the wall requirements in Figure 502.2(1) of the 2003 IECC. While
multifamily residential construction has a much smaller market share
than single-family in terms of number of dwelling units, there is a
nearly universal improvement in requirements for multifamily buildings
regardless of building design or climate zone. As indicated below in
the certification discussion, high-rise (greater than three stories)
multifamily residential buildings and hotel, motel, and other transient
residential building types of any height as commercial buildings for
energy code purposes. However, the building envelope revisions in 2006
IECC would impact residential buildings such as townhouses, row houses,
and low-rise multifamily buildings (not greater than three stories)
such as condominiums and garden apartments.
C. 2009 IECC Compared With the 2006 IECC
Each of the major changes in the 2009 IECC that impact energy
efficiency is examined individually below. All but one of the changes
appear to improve energy efficiency.
1. Changes That Improve Energy Efficiency
Lighting
The 2009 IECC has a major new requirement that a minimum of 50% of
all lamps (bulbs, tubes, etc.) be ``high efficacy,'' which is defined
to include compact fluorescent lights (CFLs), T-8 or smaller diameter
fluorescent tubes, or other products achieving comparable or better
lumen-per-watt ratings. Traditional incandescent bulbs do not meet this
requirement. The 2006 IECC had no lighting requirements for residential
buildings. The Department estimates that lighting consumed 11.6% of all
primary energy use in residential buildings in 2006 and that the
requirement in the 2009 IECC could reduce lighting energy use by about
25%.
Building Envelope Thermal Measures
The 2009 IECC has a number of changes that improve energy
efficiency in the building envelope. There are direct increases in
prescriptive building envelope requirements in Tables 402.1.1 and
402.1.3 of the IECC. Table 7 shows these changes. Additionally, there
were a number of minor improvements, including establishing an area
limit of 24 ft\2\ on the door exemption from U-factor requirements.
[[Page 54138]]
Table 7--Improvements in Prescriptive Envelope Requirements
------------------------------------------------------------------------
Component 2006 IECC 2009 IECC
------------------------------------------------------------------------
Maximum fenestration U-factor Zone 2: 0.75...... Zone 2: 0.65.
(excluding skylights). Zone 3: 0.65...... Zone 3: 0.50.
Zone 4: 0.40...... Zone 4: 0.35.
Maximum fenestration solar heat 0.40.............. 0.30.
gain coefficient (SHGC) in
Zones 1 through 3.
Basement wall insulation in R-13 cavity or R- R-19 cavity or R-
Zones 6 through 8. 10 continuous 15 continuous
insulation. insulation.
Basement wall insulation in No insulation R-13 cavity or R-5
northern section of Zone 3. required. continuous
insulation.
Wood-Frame wall insulation (all R-19.............. R-20.
but basements) in Zones 5 and 6.
Floor insulation in Zones 7 and R-30.............. R-38.
8.
------------------------------------------------------------------------
Building Envelope Air Leakage
Although the fundamental requirement to seal all potential sources
of leaks has not changed, the air leakage control specifications in
Section 402.4 of the 2009 IECC are considerably more detailed than in
the 2006 edition, requiring either a comprehensive inspection against a
checklist of component sealing criteria or a whole-building
pressurization test. There is a new requirement that fireplaces have
gasketed doors to limit air leakage. Additionally, compliance with
Standard ASTM E283 is now required to limit air leakage through
recessed light fixtures. The 2006 IECC only required recessed light
fixtures to be sealed but did not require compliance with the ASTM
standard. This testing of fixtures is expected to help eliminate energy
consuming leaks through these fixtures, which can be a very common
method of lighting in kitchens and other rooms in new houses.
Duct Leakage Limits and Testing Requirement
The 2009 IECC contains a new requirement that buildings with ducts
that pass outside the conditioned space (for example, if ducts are in
unconditioned attics, garages or crawlspaces) have the ducts pressure
tested and shown to have a maximum leakage rate below specified limits.
While the 2006 IECC also requires ducts to be sealed, the addition of a
specific leakage limit verified by a pressure test in each new home or
retrofit is expected to substantially reduce leakage in many if not
most cases.
Testing of completed homes in Washington State where prescriptive
code requirements for duct sealing apply without any testing to confirm
compliance, ``showed no significant improvement'' over non-code
homes.\4\ Another study from Washington State concluded: ``Comparisons
to air leakage rates reported elsewhere for homes built before the
implementation of the 1991 WSEC show no significant improvement by the
general population'' despite years of training emphasizing duct
sealing.\5\
---------------------------------------------------------------------------
\4\ Washington State University. 2001. Washington State Energy
Code Duct Leakage Study Report. WSUCEEP01105. Washington State
University Cooperative Extension Energy Program, Olympia,
Washington.
\5\ Hales, D., A. Gordon, and M. Lubliner. 2003. Duct Leakage in
New Washington State Residences: Findings and Conclusions. ASHRAE
Transactions. KC-2003-1-3.
---------------------------------------------------------------------------
Numerous other studies around the nation show substantial duct
leakage in new homes, including those in states with codes requiring
duct sealing. For example, a 2001 study of 186 houses built under the
Model Energy Code in Massachusetts reported ``serious problems were
found in the quality of duct sealing in about 80% of these houses''.\6\
Pressurization tests in 22 of these houses found an average leakage to
the outside of the house of 183 cfm, or 21.6% of the system flow, at a
pressure of 25 Pascals.
---------------------------------------------------------------------------
\6\ Xenergy. 2001. Impact Analysis Of The Massachusetts 1998
Residential Energy Code Revisions. https://www.mass.gov/Eeops/docs/dps/inf/inf_bbrs_impact_analysis_final.pdf.
---------------------------------------------------------------------------
The energy savings of improved duct sealing are very substantial. A
California study estimated a sales-weighted state annual average
savings from duct sealing of 38 therms and 239 kWh for a 1761 ft \2\
house.\7\ This is based on an estimated 12% improvement in duct
efficiency based on previous studies indicating a 12-15% improvement
potential. The Department preliminarily concludes that the 2009 IECC's
requirement that duct air leakage meet an upper limit and be verified
by a pressure test will save significant energy compared to the 2006
and prior editions of the IECC.
---------------------------------------------------------------------------
\7\ Hammon, R. W., and M. P. Modera. 1999. ``Improving the
Efficiency of Air Distribution Systems in New California Homes-
Updated Report.'' Consol. Stockton, California. https://www.energy.ca.gov/title24/ducttape/documents/IMPROVE_EFFICIENCY_RES.PDF.
---------------------------------------------------------------------------
Improvement in Other Requirements
1. There are a number of changes to the ``simulated performance
alternative'' compliance path in the 2009 IECC. The glazing area in the
baseline ``standard reference design'' was reduced from a maximum of
18% of the conditioned floor area to 15%. This results in increased
energy efficiency for any proposed design having a glazing area of more
than 15%. Because use of this compliance path is completely optional,
these savings will only occur when the user chooses this compliance
path. Another change does not directly alter code stringency in the
performance path but may ultimately result in some energy savings is
the removal of the option to trade high-efficiency HVAC equipment for
reductions in other requirements in the code, such as reduced envelope
insulation. Because building envelopes have substantially longer lives
than HVAC and/or water heating equipment, energy savings from envelope
improvements may persist for many more years than comparable equipment
improvements. Also, because high-efficiency equipment is already the
predominant choice in many markets, disallowing envelope/equipment
trade-offs is likely to result in improved overall efficiency in many
situations.
2. Changes That Reduce Energy Efficiency
There is only one change in the 2009 IECC that directly reduces
energy efficiency. Insulation requirements for many ducts outside the
building thermal envelope are reduced from R-8 to R-6; exceptions are
supply ducts in attics, which must still have R-8 insulation, and ducts
in floor trusses, which retain the 2006 code's R-6 requirement.
3. Net Impact on Energy Efficiency
The Department has conducted an energy simulation analysis of 2009
IECC compared to the 2006 using the DOE-
[[Page 54139]]
2 simulation tool to model \8\ a two-story, single-family house with a
crawl space foundation and a conditioned floor area of 2,400 ft.\2\ It
was assumed that the house had 8.5-ft high ceilings, a ceiling area
(bordering the unconditioned attic) of 1,200 ft \2\, a gross exterior
wall area of 2,380 ft\2\, and a window area of 357 ft \2\ (15% of the
wall area) equally oriented north, south, east, and west. Heating with
a natural gas furnace ($1.20/therm) and central electric air
conditioning ($.12/kWh) were assumed.
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\8\ The DOE-2 simulation tool is available at https://doe2.com/.
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High-efficacy lighting was assumed to increase from 10% to 50% of
all lighting within the building, reducing lighting energy use by 26%,
or $74 a year. Savings attributable to the lighting requirements in the
IECC will decrease as Federal law requires improved light bulbs in 2012
to 2014. Improved duct sealing was assumed to save 10% of the heating
and cooling costs. Figure 1 shows the estimated annual energy cost
savings resulting from the 2009 IECC changes for 14 diverse climates
and for the national average. Actual savings will vary depending on
many factors, including how well ducts are currently sealed in the
absence of any testing requirements.
[GRAPHIC] [TIFF OMITTED] TN03SE10.000
III. Comparison of the 2009 IRC to the 2009 IECC
In the past some states have adopted the 2009 International
Residential Code (IRC) in lieu of the 2009 IECC because the IRC
provides a comprehensive building construction code (structural,
plumbing, electrical, energy, etc.) in a single book for one- and two-
family dwellings and townhouses. Consequently, DOE anticipates that
some states may wish to adopt the 2009 IRC in lieu of the 2009 IECC. In
order to provide technical assistance to States that may wish to adopt
the 2009 IRC, DOE has evaluated the 2009 IRC to compare the stringency
of its energy provisions with those of the 2009 IECC. Our analysis
indicates that the 2009 IRC would not equal or exceed the energy
efficiency of the 2009 IECC.
Chapter 11 of the IRC contains energy efficiency provisions. The
IRC allows compliance with the IECC as an alternative to complying with
Chapter 11. Most of the energy efficiency requirements in the IRC and
IECC are identical. However, there are several differences between the
two codes that result in the 2009 IRC having reduced energy efficiency
compared to the 2009 IECC. All the differences are listed below.
1. The 2009 IECC requires a glazed fenestration solar heat gain
coefficient (SHGC) of 0.30 or lower whereas the 2009 IRC requires a
higher (less stringent) SHGC of 0.35 or lower, in climate zones 1, 2,
and 3. Further, the 2009 IRC allows impact resistant fenestration in
zones 1 through 3 to meet an even less stringent SHGC requirement of
0.40 and less stringent U-factor requirements in zones 2 and 3.
2. For basement walls, the 2009 IECC requires either R-15
continuous insulation or R-19 cavity insulation in zones 6-8, whereas
the 2009 IRC requires lower (less stringent) R-values in these zones:
R-10 continuous or R-15 cavity.
3. The 2009 IECC requires R-38 floors in zones 7 and 8; the 2009
IRC requires only R-30.
[[Page 54140]]
4. The 2009 IECC limits the allowance for R-30 insulation in
ceilings without attics to 500 ft\2\ or 20% of the total insulated
ceiling area, whichever is less. The 2009 IRC limits the allowance to
500 ft\2\ without regard to the total ceiling area. Thus, under the
2009 IRC some smaller homes will have less efficient ceilings.
The 2009 IRC differs from the 2009 IECC in some ways that, although
they do not reduce the stringency of code requirements, have the
potential to result in increased energy consumption in certain
situations:
1. Both the IRC and IECC allow for ``trade-offs'' by which the
efficiency of one building component can be lowered in trade for higher
efficiency in another. The 2009 IECC limits the extent to which glazing
properties can be reduced in such trade-offs. The 2009 IECC sets a
trade-off ``cap'' on SHGC at a maximum of 0.50 in climate zones 1, 2,
and 3 and a cap on U-factor trade-offs of U-0.48 in zones 4 and 5 and
U-0.40 in zones 6, 7, and 8. These caps are not present in the 2009
IRC. As these caps do not increase stringency of the code (but rather
restrict trade-off options), there is no direct impact on annual energy
consumption or cost. There may, however, be some impacts on occupant
comfort and/or resistance to moisture condensation, either of which
could possibly induce occupants to increase energy consumption, for
example by raising thermostat set points.
2. The air barrier and insulation inspection requirements differ
slightly between the codes. The 2009 IECC requires checking that ``Air-
permeable insulation is inside of an air barrier'' (right column in the
first row). The 2009 IRC is missing this, which could result in
insulation on the exterior side of an air barrier being exposed to
wind-induced air movement that reduces its effective R-value.
3. The definitions of ``conditioned space'' are different between
the two codes, which, depending on local officials' interpretations,
could result in different portions of a building being deemed
conditioned and hence subject to the code's envelope requirements.
4. The three labels ``mandatory,'' ``prescriptive,'' and
``performance'' are used to label many sections in the 2009 IECC, but
are not used at all in the 2009 IRC. The provisions that are mandatory
are always required while prescriptive provisions can be traded off as
long as overall home energy efficiency is not decreased. Thus the 2009
