Energy Conservation Program for Consumer Products: Test Procedure for Residential Central Air Conditioners and Heat Pumps, 59906-59934 [07-5142]

Agencies

• DEPARTMENT OF ENERGY

[Federal Register Volume 72, Number 203 (Monday, October 22, 2007)]
[Rules and Regulations]
[Pages 59906-59934]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 07-5142]



[[Page 59905]]

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Part III





Department of Energy





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10 CFR Part 430



Energy Conservation Program for Consumer Products: Test Procedure for 
Residential Central Air Conditioners and Heat Pumps; Final Rule

Federal Register / Vol. 72, No. 203 / Monday, October 22, 2007 / 
Rules and Regulations

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DEPARTMENT OF ENERGY

10 CFR Part 430

[Docket No. EE-RM/TP-02-002]
RIN 1904-AB55


Energy Conservation Program for Consumer Products: Test Procedure 
for Residential Central Air Conditioners and Heat Pumps

AGENCY: Department of Energy.

ACTION: Final rule.

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SUMMARY: The Department of Energy (DOE) is amending its test procedure 
for residential central air conditioners and heat pumps. This final 
rule implements test procedure changes for small-duct, high-velocity 
systems, two-capacity units, and updates references to the current 
American Society of Heating, Refrigerating, and Air-Conditioning 
Engineers (ASHRAE) standards. Today's rule also clarifies issues 
associated with sampling tested systems and rating untested split-
system combinations.

DATES: This rule is effective April 21, 2008. Incorporation by 
reference of certain publications in the final rule is approved by the 
Director of the Federal Register as of April 21, 2008.

ADDRESSES: You may review copies of all materials related to this 
rulemaking at the U.S. Department of Energy, Forrestal Building, Room 
1J-018 (Resource Room of the Building Technologies Program), 1000 
Independence Avenue, SW., Washington, DC, (202) 586-9127, between 9 
a.m. and 4 p.m., Monday through Friday, except Federal holidays. Please 
call Ms. Brenda Edwards-Jones at the above telephone number for 
additional information regarding visiting the Resource Room. Please 
note: DOE's Freedom of Information Reading Room (formerly Room 1E-190 
at the Forrestal Building) is no longer housing rulemaking materials.

FOR FURTHER INFORMATION CONTACT: Michael G. Raymond, U.S. Department of 
Energy, Office of Energy Efficiency and Renewable Energy, EE-2J, 1000 
Independence Avenue, SW., Washington, DC 20585-0121, (202) 586-9611, e-
mail: michael.raymond@ee.doe.gov; or Francine Pinto, Esq., U.S. 
Department of Energy, Office of the General Counsel, GC-72, 1000 
Independence Avenue, SW., Washington, DC 20585-0121, (202) 586-9507, e-
mail: Francine.Pinto@hq.doe.gov.

SUPPLEMENTARY INFORMATION:
I. Introduction
    A. Authority
    B. Background
    C. Summary of the Test Procedure Revisions
II. Discussion of Comments
    A. Frost Accumulation Test Duration
    B. Multiple-Split Systems
    C. Defining ``Repeatable'' for Cyclic Tests
    D. Outdoor Air Test Conditions for Units Having a Two-Capacity 
Compressor
    E. Air Volume Rate Less Than Manufacturer's Specified Value
    F. Updating References to Industry Standards
    G. Maximum and Minimum Speed Values for Calculating 
NQ and NE
    H. Using the Default or Tested Value of Cyclic-Degradation 
Coefficient
    I. Guidance on the Inclusion of Pre-Production Units in the 
Sample Population
    J. Clarification of the Sample Population Used To Validate the 
Rated Seasonal Energy Efficiency Ratio and Heating Seasonal 
Performance Factor of Heat Pumps
    K. Clarification of the Definition of a ``Highest-Sales-Volume 
Combination''
    L. Upper Limit on the Difference Between Calculated and Tested 
Seasonal Energy Efficiency Ratio and Heating Seasonal Performance 
Factor Values
    M. Clarification of the Published Ratings for Untested Split-
System Combinations
    N. Ratings That Are Based on Using a Particular Furnace or 
Ducted Air Mover
    O. Revisions to the Definition of ``Coil Family''
III. Summary of Other Additions, Changes, and Corrections to the 
Department of Energy Residential Central Air Conditioner and Heat 
Pump Test Procedure
IV. Effect of Test Procedure Revisions on Compliance With Standards
V. Procedural Requirements
    A. Review Under Executive Order 12866
    B. Review Under the Regulatory Flexibility Act
    C. Review Under the Paperwork Reduction Act of 1995
    D. Review Under the National Environmental Policy Act of 1969
    E. Review Under Executive Order 13132
    F. Review Under Executive Order 12988
    G. Review Under the Unfunded Mandates Reform Act of 1995
    H. Review Under the Treasury and General Government 
Appropriations Act, 1999
    I. Review Under Executive Order 12630
    J. Review Under the Treasury and General Government 
Appropriations Act, 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
    M. Congressional Notification
VI. Approval of the Office of the Secretary

I. Introduction

A. Authority

    Part B of Title III of the Energy Policy and Conservation Act 
(EPCA) established the Energy Conservation Program for Consumer 
Products Other Than Automobiles (Program). (42 U.S.C. 6291 et seq.) The 
products currently subject to this Program (covered products) include 
central air conditioners and heat pumps, the subject of today's final 
rule.
    Under EPCA, the Program consists of three parts: Testing, labeling, 
and the Federal energy conservation standards. DOE, in consultation 
with the National Institute of Standards and Technology (NIST), is 
authorized to establish or amend test procedures as appropriate for 
each of the covered products. (42 U.S.C. 6293) The purpose of these 
test procedures is to measure energy efficiency, energy use, or 
estimated annual operating cost of a covered product during a 
representative, average use cycle or period of use. The test procedure 
must not be unduly burdensome to conduct. (42 U.S.C. 6293(b)(3))
    If a test procedure is amended, DOE is required to determine to 
what extent, if any, the proposed new test procedure would alter the 
measured energy efficiency of any covered product as determined under 
the existing test procedure. (42 U.S.C. 6293(e)(1)) If DOE determines 
that an amended test procedure would alter the measured energy 
efficiency of a covered product, DOE is required to amend the 
applicable energy conservation standard with respect to such test 
procedure. In determining any such amended energy conservation 
standard, DOE is required to measure the energy efficiency or energy 
use of a representative sample of covered products that minimally 
comply with the existing standard. The average efficiency or energy use 
of this representative sample, tested using the amended test procedure, 
constitutes the amended standard. (42 U.S.C. 6293(e)(2)) DOE has 
determined that today's amended test procedure does not alter the 
measured efficiency or measured energy use of minimally compliant 
central air conditioners and heat pumps.
    Beginning 180 days after a test procedure for a covered product is 
prescribed, no manufacturer, distributor, retailer, or private labeler 
may make representations with respect to the energy use, efficiency, or 
cost of energy consumed by such product, except as reflected in tests 
conducted according to the DOE procedure. (42 U.S.C. 6293(c)(2)) Any 
manufacturer, distributor, retailer, or private labeler may petition 
the Secretary of Energy for an extension of not more than 180 days to 
test and make representations in accordance with the amended DOE test 
procedure. (42 U.S.C. 6293(c)(3)) In addition, all existing waivers 
concerning residential multi-split

[[Page 59907]]

systems terminate on the effective date of today's final rule.

B. Background

    A final rule published on October 11, 2005, updated and completely 
re-organized the DOE residential central air conditioner and heat pump 
test procedure. 70 FR 59122. During this prior rulemaking, a few issues 
were identified too late in the process to allow them due 
consideration. DOE investigated these issues and considered additional 
topics that could further improve the testing and rating process. As a 
result of these efforts, DOE issued a Notice of Proposed Rulemaking on 
July 20, 2006 (hereafter referred to as the July 2006 proposed rule). 
71 FR 41320. Although the majority of the proposed changes pertained to 
the test procedure set forth in appendix M to subpart B of Title 10, 
Code of Federal Regulations, Part 430 (10 CFR part 430), DOE also 
proposed revisions to sections of subparts B and F of 10 CFR part 430 
that concern the sampling of tested units and the ratings of untested 
split-system combinations. 10 CFR 430.24 and 430.62. DOE held a public 
meeting on the July 2006 proposed rule on August 23, 2006.
    On October 10, 2006, DOE published a Federal Register notice 
correcting two inadvertent omissions in the July 2006 proposed rule. 71 
FR 59410. These omissions contained the regulatory language governing 
the criterion for using an air volume rate that is less than the 
manufacturer's specified value: One case covered air conditioners and 
heat pumps, the other case covered heating-only heat pumps. This change 
was described in the preamble of the July 2006 proposed rule, but was 
not included in the regulatory language. In addition to publishing the 
corrected regulatory language in the Federal Register, the omitted 
regulatory language was distributed at the August 23, 2006, public 
meeting.

C. Summary of the Test Procedure Revisions

    The revisions adopted in today's final rule include the following 
changes to appendix M of Subpart B of 10 CFR part 430: (1) Adding new 
testing requirements for small-duct, high-velocity systems; (2) 
reinstating the optional testing to determine the cyclic-degradation 
coefficient (CD) of a two-capacity unit when cycling on and 
off at high capacity; (3) shortening the maximum duration of the Frost 
Accumulation Tests; (4) allowing the use of default equations to 
approximate the capacity and power of a two-capacity unit when 
operating at low-capacity/stage and at an outdoor temperature of 35 
degrees Fahrenheit ([deg]F); (5) implementing modifications and 
additions that specifically address elements unique to testing and 
rating modulating multi-split systems; (6) allowing indoor capacities 
used in calculating Seasonal Energy Efficiency Ratio (SEER) and Heating 
Seasonal Performance Factor (HSPF) to be corrected for duct losses; (7) 
defining the term ``standard air;'' (8) changing the outdoor 
temperature conditions used for one of the low-capacity, steady-state, 
cooling mode tests on a two-capacity unit; (9) renaming ``Cooling and 
Heating Certified Air Volume Rates'' to ``Full-Load Air Volume Rates;'' 
(10) modifying the criterion for using an air volume rate less than the 
manufacturer's specified value; (11) updating the references to current 
versions of the Air-Conditioning and Refrigeration Institute (ARI) and 
ASHRAE standards; (12) adding language to better explain the SEER and 
HSPF calculation steps for variable-speed equipment; and (13) adding 
text to clarify the provision to use the default value of the cyclic-
degradation coefficient if it is lower than the tested value.
    Today's final rule also amends sections 430.2, 430.24 and 430.62 of 
10 CFR part 430, as follows: (1) It expands the options for meeting the 
data submission requirements when verifying an alternative rating 
method (ARM); (2) it clarifies the sample population to be used to 
validate the rated SEER and rated HSPF of a heat pump; (3) it clarifies 
the definition of a ``highest-sales-volume combination'' (HSVC); (4) it 
clarifies DOE's role in verifying ratings for untested split system 
combinations; (5) it clarifies how to apply the ARM to obtain published 
ratings for untested, split-system combinations; (6) it adds the 
requirement that ratings for an air conditioner or heat pump tested 
with a furnace or similar ducted air mover include the model number of 
the air mover as part of the overall equipment model number; (7) it 
clarifies the responsibilities of private labelers; (8) it adds the 
statutory definition of ``private labeler;'' and (9) it adds 
definitions for terms, including ``indoor unit'', ``outdoor unit'', and 
``ARM/simulation adjustment factor.''

II. Discussion of Comments

    In addition to the comments received at the August 23, 2006, public 
meeting, DOE received written comments to the July, 2006 proposed rule 
from ARI, Nordyne, Mitsubishi, Fujitsu General Limited (Fujitsu), 
Carrier Corporation (Carrier), the American Council for an Energy-
Efficient Economy (ACEEE), Sanyo Fisher Service Corporation (Sanyo), 
Lennox International (Lennox), and the China WTO/TBT National 
Notification and Enquiry Center (China). The comments and the DOE 
response to them are discussed below. References to section numbers 
within this document refer to the section numbers of Appendix M to 
Subpart B of 10 CFR part 430-Uniform Test Method for Measuring the 
Energy Consumption of Central Air Conditioners and Heat Pumps (Appendix 
M).

A. Frost Accumulation Test Duration

    DOE proposed shortening the maximum test interval of a Frost 
Accumulation Test from 12 hours to 6 hours when testing a two-capacity 
heat pump at low capacity. ARI supported DOE's proposal to lessen the 
test burden, but recommended that the maximum duration be further 
shortened to 3 hours. (ARI, No. 21 at p. 2)\1\ ARI stated that 
``preliminary testing done by manufacturers shows a variation in HSPF 
of less than one tenth \2\ when the test is reduced from 12 to 3 
hours.'' (ARI, Id.) In a follow-up communication, ARI clarified that 
its 3-hour recommendation applies to all Frost Accumulation Tests, not 
just the test at low-capacity. (ARI, No. 25 at p. 2) ARI provided a 
table showing the percentage of the total interval allocated to 
defrosting for cycles lasting 6, 7, 8, 9, and 10 minutes; percentages 
were calculated for complete (frost + defrost) intervals ranging from 1 
hour to 12 hours. As an example, for tests lasting 12, 6, and 3 hours, 
the percentages of time spent defrosting are 1.1, 2.2, and 4.4 percent, 
respectively, if the defrost lasts 8 minutes in all cases. (ARI, No. 25 
at p. 3) In addition to recommending that any change be applied to all 
Frost Accumulation Tests, Nordyne and Carrier recommended manufacturers 
be given the option of using either the procedure specified in ASHRAE 
Standard 37 (which uses a maximum test interval of 3 hours) or the 
algorithm specified in the DOE test procedure. (Nordyne, No. 19 at p. 
2; Carrier, No. 17

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at p. 2) In summary, the stakeholders recommended applying changes to 
all Frost Accumulation Tests (not just to the one low-capacity test, as 
proposed), reducing the maximum duration to 3 hours instead of 6 hours, 
and adding an alternative test method.
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    \1\ A notation in the form ``ARI, No.21 at p. 2'' identifies a 
written comment the Department has received and has included in the 
docket of this rulemaking. This particular notation refers to a 
comment (1) by the Air-Conditioning and Refrigeration Institute 
(ARI), (2) in document number 21 in the docket of this rulemaking 
(maintained in the Resource Room of the Building Technologies 
Program), and (3) appearing on page 2 of document number 21. 
Likewise, ``Public Hearing Tr., p. 178,'' for example, would refer 
to page 178 of the transcript of the ``Public Meeting on Test 
Procedures for Central Air Conditioners'' held in Washington, DC, 
August 23, 2006.
    \2\ This means an absolute variation in HSPF of 0.1, such as 
between 8.1 and 8.2.
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    DOE believes that if all three changes were adopted, the HSPF 
ratings of heat pumps would be changed, since the ASHRAE Standard 37 
``T'' Test Procedure may terminate after 0, 1, 2, or 3 complete cycles 
whereas the DOE Frost Accumulation Test is either 0 or 1 complete 
cycle. The different cycles in the ASHRAE and DOE test methods can 
yield different average heating capacity and power consumption results 
at the DOE-specified 35 [deg]F dry-bulb/33 [deg]F wet-bulb outdoor test 
conditions which would affect the HSPF rating. As for shortening the 
maximum test time to 3 hours, such a change may benefit heat pumps 
(i.e., give a higher average heating capacity) that initiate a defrost 
of the outdoor coils between 3 and 6 hours after the start of the test. 
In such cases, the heat pump's average heating capacity will not 
account for the energy used for defrosting. By not accounting for the 
defrost energy, the shorter test time would overstate the heating 
capacity and HSPF. Thus, DOE will not reduce the maximum test duration 
by the additional 3 hours or add the ASHRAE Standard 37 procedure as an 
alternate test method as part of this final rule.
    DOE agrees with comments recommending the same maximum limit for 
all Frost Accumulation Tests. The low-capacity Frost Accumulation Test 
is projected to be the most likely of the 35 [deg]F tests to approach 
the proposed 6-hour limit, followed by the required Frost Accumulation 
Test at the intermediate speed when testing a variable-speed heat pump. 
All other Frost Accumulation Tests are more likely to build frost and 
are likely to result in the unit defrosting in less time than it would 
at the intermediate speed. Thus, triggering the 6-hour limit is less 
likely when applied to these other cases. Finally, DOE concludes that 6 
hours offers a sufficiently long duration for evaluating performance in 
all cases. As noted in the July 2006 proposed rule, if a heat pump has 
not defrosted in 6 hours, it is either not building frost or is 
completely frosted and probably has been so for more than half of the 
interval. In both cases, the benefits from continuing to run the test 
past 6 hours are minimal. Therefore, DOE reduces the maximum duration 
of all Frost Accumulation Tests from 12 hours to 6 hours. This change 
appears in section 3.9 of Appendix M.

B. Multiple-Split Systems

    DOE received comments on issues related to the testing and rating 
of multiple-split air-conditioning systems (multi-split systems), 
including: (1) Rating multi-split systems based on SEER (if they 
compete primarily with ducted central air conditioners), or rating them 
based on EER (if they compete with room air conditioners) (SEER or 
EER); (2) adopting a separate test procedure for multi-split systems, 
such as Draft ARI Standard 1230 (ARI 1230); (3) allowing one or more 
indoor coils to turn off during any test, if representative of normal 
operation (Coils active during test); (4) allowing the manufacturer to 
specify the compressor speed used during the minimum-speed, 
intermediate-speed and maximum-speed tests (Compressor speed); (5) 
extending multi-split system test procedure changes to one-to-one 
ducted systems (One-to-one applicability); and (6) adding the term 
``tested combination'' within 10 CFR 430.2 for determining the 
combination of indoor units to be tested when testing a multi-split 
outdoor unit, and the appropriate rating of the tested combination 
(Tested combination).
    SEER or EER. DOE received several comments on whether multi-split 
systems compete primarily with ducted residential central air 
conditioners and heat pumps and as such, should be rated based on SEER 
and HSPF, or if they compete with room air conditioners and should be 
rated in terms of EER and COP. Trane argues that residential size 
multi-split systems compete for the same markets as ducted residential 
central systems: both serve multiple rooms, one ducts air whereas the 
second ``ducts'' refrigerant. (Public Hearing Tr., p. 178) Carrier and 
ACEEE support rating conventional central air conditioners and heat 
pumps and multi-split systems using the same descriptors. (Carrier, No. 
17 at p. 1 and ACEEE, No. 16 at p. 3) According to Mitsubishi, 
``ductless split-systems, including ductless multi-split systems, are 
used for room or spot cooling applications while the rest of the USE 
[unitary small equipment] equipment (i.e., central systems) is applied 
in a ducted environment for multiple rooms or whole houses.'' 
(Mitsubishi, No. 20 at p. 3) DOE believes residential-size multi-split 
systems compete with ducted central systems and that the consumer will 
be best served if multi-split systems can be compared with central air 
conditioners and central air-conditioning heat pumps. Therefore, DOE 
concludes that SEER and HSPF are better descriptors than EER and COP.
    ARI 1230. ARI, Sanyo, Fujitsu, Mitsubishi, and Daikin AC 
(Americas), Inc. (Daikin) urged DOE to adopt Draft ARI Standard 1230, 
``Performance Rating of Multi-Split Air-Conditioning and Heat Pump 
Equipment'' in lieu of the proposed rule. (ARI, No. 21 at p. 3; Sanyo, 
No. 15 at pp. 2-3; Fujitsu, No. 13 at p. 3; Mitsubishi, No. 20 at pp. 
4-5; Public Hearing Tr., pp. 153-154) China recommends that DOE not 
cover multi-split systems within the residential central air 
conditioner and heat pump test procedure until all the technical issues 
have been resolved. (China, No. 14 at p. 1) Copeland recommends that 
DOE review and consider the approaches being taken by China and the 
European Union on how to test and rate multi-split systems. (Public 
Hearing Tr., p. 64) Nordyne supports the changes proposed in the July 
2006 proposed rule to cover multi-split systems as an interim solution, 
but states that further study is needed for a long term solution. 
(Nordyne, No. 19 at p. 2) Lennox, on the other hand, believes that 
multi-split systems should be rated using the current test procedure 
for central air conditioners and central air conditioning heat pumps. 
(Lennox, No. 22 at p. 2) Sanyo and Fujitsu point out that the test 
procedure does not address units that can simultaneously cool and heat; 
the test procedure does not specify how many indoor units are turned 
off during a given test; and doubts whether the current DOE tests for 
variable-speed systems can approximate the unit's ``performance map.'' 
\3\ (Sanyo, No. 15 at pp. 2-3; Fujitsu, No. 13 at pp. 2-3; Public 
Hearing Tr., pp. 94-95, 110)
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    \3\ Performance map refers to a plot that shows the effect of 
compressor speed, number of indoor unit turned on versus off, and 
outdoor temperature conditions on the unit's space conditioning 
capacity and power consumption.
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    DOE is not convinced that residential-size multi-split systems 
require a separate test procedure from the current test procedure found 
in Appendix M. While it is true that the current test procedure fails 
to account for the energy savings derived from a simultaneous cooling 
and heating mode, the current test procedure is adaptable and DOE 
believes the tests for variable-speed systems in Appendix M offer a 
reasonable starting point for producing energy efficiency and energy 
use estimates. Once data become available that provides insight as to 
the energy use and efficiency benefits of simultaneous cooling and 
heating, and alternative or additional tests to estimate these benefits 
are formulated, DOE will then consider further

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amendments to the test procedure. Accordingly, DOE is not adopting a 
new test procedure and energy efficiency and energy use ratings will 
continue to be based on the test procedure found in Appendix M.
    Regarding the stakeholder recommendation to adopt draft ARI 
Standard 1230, the current draft (as distributed in June 2007), is less 
complete for residential multi-split systems than the DOE test 
procedure in today's final rule. For example, ARI Standard 1230 (June 
2007 draft) lacks information on how to conduct intermediate speed 
tests, whether any indoor units are to be turned off for part-load 
tests, how to interpolate EER and COP in the intermediate speed range, 
and generally how to calculate SEER and HSPF. Furthermore, ARI has not 
finalized ARI Standard 1230 and, as such it cannot be incorporated by 
reference since it could be amended prior to being adopted in final 
form. Therefore, for the reasons discussed above, DOE is not adopting 
ARI Standard 1230 (June 2007 draft) in today's final rule.
    As for considering changes that are modeled on the approaches taken 
in China and the European Union, DOE sees their potential use as 
limited given the current EPCA requirement to calculate annual measures 
of energy consumption. The European Union HVAC trade association, 
Eurovent, lists ratings for residential-size multi-splits that are 
based on full load EER and COP and their European SEER (ESEER) is thus 
far limited to liquid chilling packages, not unitary air conditioners 
(i.e., residential central air conditioners and central air 
conditioning heat pumps). The ESEER is actually a variation of ARI 
Standard 340/360's IPLV, which is used to quantify the part-load 
performance of larger, non-residential systems. An IPLV equivalent is 
also used in China. Neither international resource explicitly addresses 
the number of indoor units to be turned off during a given part-load 
test; such information would be necessary in order to get an accurate 
measure of equipment efficiency for comparison purposes.
    Coils active during test. Concerning the issue of whether one or 
more indoor units should be turned off during any given test, Daikin 
commented that you cannot rely on the unit's controls to make the 
decision when operated in a laboratory environment. (Public Hearing 
Tr., p. 62) Given this, DOE offered, at the public meeting, an 
algorithm for specifying the number of indoor units that are turned on 
for a given test. This algorithm is shown in Table 1, below. To 
evaluate the effect of such an algorithm, Fujitsu conducted simulations 
in which it modeled the performance of a unit if operated at the DOE 
test procedure cooling mode conditions. Fujitsu considered cases where 
the number of indoor units turned on for the two minimum speed and one 
intermediate speed tests changed. Fujitsu reported results for three 
cases: the first case, all four indoor units are on for all tests; the 
second case, three indoor units are on for the intermediate speed test 
and two indoor units are on for the minimum speed tests; and the third 
case, two indoor units are on for the intermediate-speed test and one 
indoor unit is on for the minimum speed tests. (Fujitsu, No. 13 at pp. 
1-2) Using the simulated data, Fujitsu reported that the first case 
yields the highest SEER. In comparison, Fujitsu reported that the SEER 
drops by 4.7 percent for the second case and by 11.6 percent for the 
third case. Fujitsu concluded that the number of operating indoor units 
may have a great impact on the result, and that the operating ranges in 
Table 1 were not appropriate.

   Table 1.--Approach to Regulating the Number of Active Indoor Units
 (Example Case of a Multi-Split System Having 4 Identical Indoor Units)
------------------------------------------------------------------------
                                                             Number of
    Percentage output relative to full load capacity         operating
                                                           indoor units
------------------------------------------------------------------------
75% to 100%.............................................               4
50% to 75%..............................................               3
25% to 50%..............................................               2
0% to 25%...............................................               1
------------------------------------------------------------------------
(DOE, No. 12.3 at p. 12)

    DOE recognizes that when field installed, a multi-split system will 
often operate with one or more of its indoor units turned off. In an 
effort to have the DOE test procedure capture this part-load operating 
mechanism, today's final rule requires that at least one indoor unit 
must be turned off for tests conducted at minimum compressor speed. In 
addition, the manufacturer may elect to have one or more indoor units 
turned off for tests conducted at the intermediate compressor speed. In 
all cases, the manufacturer specifies the particular indoor unit(s) 
that is turned off.
    Compressor speed. ARI, Sanyo, Fujitsu, and Mitsubishi opposed DOE's 
proposed definition of maximum compressor speed. (ARI, No. 21 at p. 2; 
Sanyo, No. 15 at p. 2; Fujitsu, No. 13 at p. 2; Mitsubishi, No. 20 at 
p. 4) They recommended using the rated capacity or nominal rated speed 
because performance at that compressor speed is used in sizing and 
selling the product. ARI and Sanyo supported DOE's proposal to allow 
the manufacturer to specify the compressor speed used for the minimum-
speed and intermediate-speed tests. (ARI, No. 21 at p. 2; Sanyo, No. 15 
at p. 2) Sanyo and ARI, moreover, both believe that test laboratories 
must accept the task of providing test facilities that can maintain 
steady test room conditions and accurately measure capacity at very low 
loads. (ARI, No. 21 on pp. 2-3; Sanyo, No. 15 on p. 2)
    Regarding the maximum and minimum compressor speed issue, DOE 
reviewed test procedure waivers processed in the 1980's, and the 1988 
test procedure rulemaking that first added coverage for air 
conditioners and heat pumps having a variable-speed compressor. (53 FR 
8304, March 14, 1988) None of these actions explicitly defined maximum 
and minimum compressor speed. Instead, the manufacturer was allowed to 
define these speeds for its particular units. The evolution to include 
maximum and minimum compressor speeds among those elements that are 
``conducted in accordance with the manufacturer's instructions'' 
occurred because of the test laboratory's need for a mechanism to 
override the unit's normal controls, so that the compressor can be 
forced to operate at fixed speeds for the DOE-specified lab tests. As 
part of today's final rule, DOE considered adopting a specific 
definition for maximum speed and requiring additional lab verification 
tests, but has decided against it because there is no compelling 
technical argument for doing so. The current approach effectively 
allows the manufacturer to de-rate the unit's maximum capacity in order 
to raise its performance descriptor. As long as that de-rated capacity 
is used for sizing the particular multi-split combination, then the 
practice is acceptable. DOE, however, does not agree with substituting 
``nominal'' or ``rated'' compressor speed for ``maximum'' compressor 
speed, as that will not allow for test results that can be used to 
generate a performance map representing how particular multi-split 
combinations will operate in the field.
    The DOE test procedure will continue to require variable-speed 
systems to be tested at their minimum compressor speed. Manufacturers 
will be relied upon to provide the independent testing laboratory with 
a means for conducting tests at this speed. Minimum speed may not be 
the absolute minimum speed at which the compressor can operate, but

[[Page 59910]]

it is expected to be a speed below which the compressor would rarely 
operate. DOE concurs with Sanyo and ARI and expects test laboratories 
to measure performance over the wide modulation range that is 
characteristic of multi-splits. Thus, to the issue of what compressor 
speed to use when conducting minimum speed and maximum speed tests, DOE 
is maintaining the current test procedure language in sections 3.2.4 
and 3.6.4 of Appendix M.
    DOE adopts the July 2006 proposed change of allowing the 
manufacturer to specify the compressor speed used for the cooling and 
heating intermediate speed/capacity tests. This change provides the 
manufacturer an opportunity to select and verify the peak-efficiency of 
the unit being tested. Coupled with this change, and as also proposed 
in the July 2006 notice, steady-state efficiency (EER and COP) over the 
intermediate-speed range shall be calculated using piece-wise linear 
fits: a line connecting the minimum- and intermediate-speed balance 
points and a line connecting the intermediate- and maximum-speed 
balance points.
    One-to-one applicability. Carrier noted the need for transparency 
in testing and manufacturer test results so that interested parties can 
verify the performance claims without having to consult the 
manufacturer. (Carrier, No. 17 at p. 2) Trane and ARI pointed out that 
any steps introduced to facilitate testing and rating modulating multi-
split systems should also be allowed for modulating one-to-one ducted 
systems to promote comparability. (Public Hearing Tr., pp. 87 and 118; 
ARI, No. 21 at p. 3) With respect to Carrier's comment, variable-speed 
systems do not lend themselves to being tested by a third party who 
does not have the cooperation of the outdoor unit manufacturer. Third-
party certification programs thus become especially important as they 
offer the primary pathway for independent verification. For those 
multi-split products that are not covered by a third-party 
certification program, DOE can request from the manufacturer the 
information needed to conduct such testing along with reviewing the lab 
test results maintained by the manufacturer, that substantiate the 
multi-split system's ratings. 10 CFR 430.62(d).
    Of the changes being implemented today to allow testing and rating 
of residential modulating multi-split systems, two changes could be 
applied to variable-speed one-to-one units. Together, these two changes 
would allow the manufacturer to specify the compressor speed used for 
the intermediate-speed tests and then use linear fits for calculating 
COP and EER within the intermediate-speed operating range. Adopting 
these two changes for variable-speed one-to-one units would create a 
second compliance path that would likely cause different SEER and HSPF 
ratings than the current test procedure. Therefore, in adopting these 
changes, DOE is not extending them to variable-speed one-to-one units. 
Although DOE expects the current test procedure to yield the higher 
ratings for one-to-one units, it will rely on the waiver process if any 
manufacturer seeks to adopt these two multi-split test procedure 
changes for use in rating variable-speed one-to-one units.
    Tested combination. On the issue of the ``tested combination''--the 
equipment configuration that can be tested in the laboratory and 
thereby provide a common basis for comparison--Sanyo, Fujitsu, 
Mitsubishi, and ARI recommended deleting the requirement that the 
selected indoor units ``represent the highest-sales-volume type 
models'' and replacing it with ``represent the highest sales model 
family.'' (Sanyo, No. 15 at p. 3; Fujitsu, No. 13 at p. 4; Mitsubishi, 
No. 20 at pp. 5 and 6; ARI, No. 21 at p. 6) In addition, Sanyo, 
Fujitsu, Mitsubishi, and ARI recommended that provisions be made in the 
event that five of the largest model indoor coils from the selected 
model family cannot provide a cumulative indoor capacity that is more 
than 95 percent of the outdoor unit's nominal capacity. As to 
references in the proposed definition that a manufacturer will know the 
capacity of each indoor unit and each outdoor unit, Copeland 
Corporation (Copeland) questioned how the manufacturer would determine 
component capacities. (Public Hearing Tr., pp. 217-221) Finally, with 
regard to the proposal that all of the tested indoor units ``have the 
same external static pressure,'' Trane asked how to interpret that 
requirement if testing a ducted multi-split system having indoor units 
that have different minimum external static pressure requirements. 
(Public Hearing Tr., p. 229)
    DOE accepts the stakeholder recommendation of substituting the 
phrase ``represent the highest sales model family'' for the originally 
proposed wording, ``represent the highest sales volume type models,'' 
because it has essentially the same meaning, but is clearer. Although 
it is more an issue with commercial multi-split systems, DOE accepts 
the proposed wording to clarify the tested combination since it is more 
important to obtain a cumulative indoor capacity that matches the 
outdoor unit than it is to restrict selection to units from the highest 
sales model family, for cases where both criteria cannot be met. As for 
Copeland's statement that the definition includes references to the 
capacity of the outdoor unit and the cumulative capacities of the 
indoor units even though no prescriptions are given to evaluate these 
capacities, DOE agrees but nonetheless will allow their use in this 
particular definition. Manufacturers are able to estimate the rated 
capacities of the separate components without conducting the rigorous 
testing associated with ARI Standards 410 (``Forced-Circulation Air-
Cooling and Air-Heating Coils'') and 540 (``Performance Rating of 
Positive Displacement Refrigerant Compressors and Compressor Units'') 
on each new model. Finally, the last element of the proposed definition 
of ``tested combination'' will be changed from ``all have the same 
external static pressure'' to ``all be subject to the same minimum 
external static pressure requirement (i.e., 0 inches of water column 
for non-ducted, see Table 2 in Appendix M for ducted indoor units) 
while being configurable to produce the same static pressure at the 
exit of each outlet plenum when manifolded as per section 2.4.1 of 
Appendix M.'' This additional information is provided so that the test 
laboratory may conduct the lab testing by manifolding the outlets of 
all the indoor units together and using one airflow measuring apparatus 
to determine the cumulative air volume rate.
    At the August 23, 2006, public meeting, DOE restated its proposed 
interim solution for assigning SEER and HSPF ratings for untested 
multi-split combinations. This interim solution--to assign the rating 
measured for the tested combination to every other combination using 
the same outdoor unit--was included as part of the March 24, 2006, 
Federal Register notice that published a petition for waiver from the 
residential package air conditioner and heat pump test procedures that 
was received from Mitsubishi Electric and Electronics USA, Inc. (Case 
No. CAC-012). 71 FR 14858. This provision was not in the July 2006 
proposed rule, but was discussed at the public meeting and relevant 
comments were received in the course of the waiver process. Lennox and 
Copeland commented that the rated system's combination of indoor units 
could be very different from those in the tested system, and the 
ratings agreement would be poor in this case. (Public Hearing Tr., pp. 
245-246)
    Because of the difficulty of prescribing similarity of indoor unit

[[Page 59911]]

combinations, and with the belief that a rating that reflects the 
``highest sales model family'' is better than no rating, DOE is 
including this ratings provision in the final rule, with the additional 
stipulation that multi-split manufacturers must test two or more 
combinations with each outdoor unit unless they have an approved ARM 
(in which case, they only need to test one combination). 10 CFR 
430.24(m)(2). One system shall be tested using only non-ducted indoor 
units that meet the definition of a tested combination. The second 
system shall be tested using only ducted indoor units that meet the 
definition of a tested combination. The rating given to any untested 
multi-split system combination having the same outdoor unit and all 
non-ducted indoor units shall be set equal to the rating of the tested 
system having all non-ducted indoor units. The rating given to any 
untested multi-split system combination having the same outdoor unit 
and all ducted indoor units shall be set equal to the rating of the 
tested system having all ducted indoor units. Finally, the rating given 
to any untested multi-split system combination having the same outdoor 
unit and a mix of non-ducted and ducted indoor units shall be set equal 
to the average of the ratings for the two required tested combinations. 
10 CFR 430.24(m)(2)(ii). Furthermore, DOE notes that it is including a 
provision for the use of an alternate rating method. While DOE is not 
aware of any algorithms appropriate for rating the energy efficiency of 
untested multi-split system combinations, DOE expects that as more 
laboratory test data and field use data become available, such 
algorithms will be developed.
    Today's final rule contains a minor update that was introduced in 
the July 2006 proposed rule, removing the limit on having only one 
indoor test room. No comments were received on this proposed change.
    Today's final rule sufficiently addresses issues that led to the 
requesting and granting of test procedure waivers for several models of 
residential multi-split systems. Therefore, all existing waivers 
concerning residential modulating multi-split systems terminate on the 
effective date of today's final rule. Multi-split manufacturers may use 
the waiver process described in 10 CFR 430.27 to petition for 
modification of today's test procedure, if necessary.

C. Defining ``Repeatable'' for Cyclic Tests

    The July 2006 proposed rule contained two provisions that further 
defined repeatable performance during cyclic tests. One was the 
requirement that the time-integrated air temperature difference across 
the indoor unit for consecutive ``on'' cycles must change by 0.05 
[deg]F hr or less while the other was for the average system power 
consumption for the complete ``OFF/ON'' interval to change by 10 watts 
or less from one cycle to the next.
    ARI, Sanyo, Carrier, and Nordyne commented that repeatability 
should be addressed by ASHRAE's Standards Project Committee (SPC) 116, 
``Method of Testing for Rating Seasonal Efficiency of Unitary Air 
Conditioners and Heat Pumps,'' not by the DOE test procedure (ARI, No. 
21 at p. 3; Sanyo, No. 15 at p. 5; Carrier, No. 17 at p. 2; Nordyne, 
No. 19 at p. 2) Finally, ACEEE supports DOE's efforts to capture the 
essence of industry best practices for cyclic testing. (ACEEE, No. 16 
at p. 4)
    DOE recognizes that variability is inherent in testing products for 
energy efficiency, including central air conditioners and central air 
conditioning heat pumps. In order to reduce test variability and 
increase repeatability of test results, DOE has set specific 
requirements for test set-up and measurement to reduce variability. 
However, even with these requirements, test variability remains. 
Furthermore, DOE notes that the less repeatable the test, either more 
units need to be tested to support an energy efficiency rating that is 
representative of the units true energy efficiency or, if less testing 
is done, the product must be rated conservatively (i.e., lower energy 
efficiency rating).\4\ Test variability can be further reduced by, for 
example, including more specific requirements in the DOE test 
procedures as well as through industry actions, such as ASHRAE Standard 
116. However, changes to the DOE test procedures to deal with test 
variability could increase the burden and cost of testing. Since the 
purpose of this requirement was to reduce variability and there are 
alternative approaches manufacturers can take to reduce variability, 
DOE is not adopting the cyclic changes proposed. Therefore, as part of 
today's final rule, DOE makes no changes on defining repeatability 
during cyclic tests.
---------------------------------------------------------------------------

    \4\ SEER and HSPF values, per the sampling plan in 10 CFR 
430.24, are to be based on the lower 90 percent confidence limit of 
the true mean divided by 0.95 (as opposed to the sample mean), thus 
the more variability in test results, the more likely that a 
product's SEER and HSPF ratings will have to be reduced from the 
true mean.
---------------------------------------------------------------------------

D. Outdoor Air Test Conditions for Units Having a Two-Capacity 
Compressor

    The July 2006 proposed rule included provisions that dealt with the 
outdoor test conditions for three low-capacity cooling mode tests. The 
three low-capacity tests are conducted at different outdoor dry bulb 
temperatures (i.e., steady-state, wet-coil test at 95 [deg]F outdoor 
dry bulb temperature (the A1 Test); the steady-state, dry-
coil test at 82 [deg]F (the C1 Test); and the cyclic, dry-
coil test at 82 [deg]F (the D1 Test)). The July 2006 
proposal was to have all three of these tests replaced by equivalent 
tests conducted at an outdoor dry bulb temperature of 67 [deg]F.
    ARI, Carrier, and Nordyne supported replacing the A1 
Test with the steady-state, wet-coil, F1 Test at 67 [deg]F 
because the change will close a potential loophole in the current test 
procedure. (ARI, No. 21 at p. 3; Carrier, No. 17 at p. 2; Nordyne, No. 
19 at p. 2) This loophole allowed manufacturers a way to increase the 
measured SEER by disproportionately increasing the electrical power 
consumption during the A1 Test. ACEEE supported the change 
in the temperature in the A1 test, but expressed its concern 
that the change may downgrade the importance of high temperature 
performance. (ACEEE, No. 16 at p. 4) ARI, Carrier, and Nordyne 
commented that the change in the C1 and D1 tests 
is unnecessary since these tests are optional and the changes will do 
very little to improve the accuracy of SEER. (ARI, No. 21 at p. 3; 
Carrier, No. 17 at p. 2; Nordyne, No. 19 at p. 2) Carrier also 
expressed its concern that products designed and tested under the 
current methodology may have to be re-rated as a result of the 
proposal. (Carrier, No. 17 at p. 2) In terms of the test procedure, 
Carrier is concerned that a different cyclic-degradation coefficient 
(CD) may result from replacing the C1 and 
D1 Tests with equivalent tests at 67[deg]F.
    Collectively, the three proposed changes make the test conditions 
for two-capacity units consistent with the test conditions specified 
for variable-speed systems. Implementing all three changes would result 
in a more normal test progression for most two-capacity units: all wet 
coil tests followed by the dry coil test; start with high capacity 
tests and end with the low capacity tests; and start at 95 [deg]F, 
progress to 82 [deg]F, and then end with 67 [deg]F. These benefits, 
however, cannot be realized because of the possibility of causing a 
change in the SEER ratings of some two-capacity units. Thus, DOE agrees 
with the general position of the comments that the proposal to change 
the outdoor test conditions for the two optional dry-coil CD 
tests (C1 and D1 tests) is not warranted.

[[Page 59912]]

    Therefore, today's final rule replaces the A1 Test with 
the F1 Test, as proposed. The F1 Test requires an 
outdoor dry bulb temperature of 67 [deg]F, and for those few cases 
where it applies, an outdoor wet bulb temperature of 53.5 [deg]F. The 
amendments discussed above are found in sections 3.2.3 and 4.1.3 of 
Appendix M.

E. Air Volume Rate Less Than Manufacturer's Specified Value

    In the July 2006 proposed rule, and the October 10, 2006, 
correction notice, DOE proposed modifications to the criteria for using 
an air volume rate that is less than the manufacturer's specified 
value. The proposal was made to account for the variability in fan 
motors, housings, and wheels. In brief, the proposed set-up process for 
the test procedure provides for making incremental adjustments in the 
indoor fan speed until the indoor unit provides an external static 
pressure that is equal to or greater than the applicable DOE minimum 
(i.e., 0.1, 0.15, or 0.20 inch of water column, if a non-small-duct, 
high-velocity (SDHV) system), while operating at the manufacturer-
specified air volume rate or, if needed, at the air volume rate between 
95 percent and 100 percent that produces the corresponding DOE minimum 
static pressure value. For comparison, the current algorithm in the DOE 
test procedure does not allow the air volume rate to be reduced from 
100 percent for the case where the external static pressure is less 
than specified by the test procedure. The proposed criteria apply to 
all ducted blower-coil systems, except those having a variable-speed 
motor that is controlled based on maintaining a constant air volume 
rate. The proposed criteria include two cases where the test laboratory 
is instructed to operate at an air volume rate less than that specified 
by the manufacturer: (1) If the highest indoor fan speed setting cannot 
yield the DOE-specified external static pressure minimum while 
supplying the manufacturer-specified air volume rate, and (2) if the 
manufacturer's specified air volume rate yields a ratio higher than 
37.5 standard cubic feet per minute (scfm) per 1000 Btu/h.
    Nordyne, Carrier and Rheem supported the proposed criteria for 
using an air volume rate that is less than the manufacturer's specified 
value. (Nordyne, No. 19 at p. 2; Carrier, No. 17 at p. 3; Public 
Hearing Tr., p. 135; and Public Hearing Tr., pp. 134-135) ACEEE 
commented that since the proposed language specified which product 
designs would be subject to this requirement, they recommended that the 
wording for the types of indoor blowers that are affected by this 
change be as generic as possible so as not to impede product 
innovation. (Public Hearing Tr., pp. 132-133)
    DOE agrees with ACEEE that the proposed language could limit 
innovation since the proposed amendment was intended to apply to 
designs that are not adequately addressed by the current air volume 
requirements. Since it is impossible to predict what product designs 
may enter the marketplace, specifying the designs subject to the new 
provisions may, in fact, limit innovation. Therefore, in response to 
ACEEE's comment, DOE restructured the air volume criteria to indicate 
that the change applies to all designs, except variable-speed, 
constant-air-volume-rate blowers. In this way, the variable-speed, 
constant-volume-rate blowers, which the existing test procedure 
adequately addresses, continue to be subject to the existing 
requirement.

F. Updating References to Industry Standards

    The July 2006 proposed rule included updates to references to 
current industry test standards, including ASHRAE Standard 23-2005, 
``Methods of Testing for Rating Positive Displacement Refrigerant 
Compressors and Condensing Units,'' ASHRAE Standard 37-2005, ``Methods 
of Testing for Rating Electrically Driven Unitary Air-Conditioning and 
Heat Pump Equipment,'' and ASHRAE Standard 116-1995 (RA2005), ``Methods 
of Testing for Rating Seasonal Efficiency of Unitary Air Conditioners 
and Heat Pumps.'' Nordyne commented in support of this proposal. 
(Nordyne, No. 19 at p. 2)
    In addition, subsequent to the publication of the July 2006 
proposed rule, ARI released an updated version of ARI Standard 210/240, 
``Performance Rating of Unitary Air-Conditioning and Air-Source Heat 
Pump Equipment.'' The updated version of ARI Standard 210/240 included 
references to the DOE test procedure as amended by the final rule 
published on October 11, 2005. This latest version of ARI Standard 210/
240 had not been released at the time that the content of the July 2006 
proposed rule had been finalized. Since the updated test procedures do 
not affect the measure of efficiency and provide manufacturers with 
current test standards, DOE moves today to adopt the 2006 version of 
ARI Standard 210/240.

G. Maximum and Minimum Speed Values for Calculating NQ and 
NE

    Rheem inquired as to whether the minimum and maximum speed 
quantities needed to evaluate Appendix M equations 4.1.3-1 and 4.1.3-3 
are to be determined directly from additional lab testing or from 
interpolating data from required tests lab tests at 67 [deg]F, 82 
[deg]F, and 95 [deg]F. (NIST, No. 24 at p. 2) In response, for cooling 
performance, DOE modified section 4.1.4 to explicitly state that the 
capacities and Qck=1 (87) and 
Qck=2 (87), which are used as part of the 
algorithm for approximating the slope of the intermediate compressor 
speed (k=v) capacity curve, are determined by evaluating equations 
4.1.3-1 and 4.1.3-3, respectively, for Tj = 87. Similar 
direction is provided for determining the power consumption quantities 
Eck=1 (87) and Eck=2 (87) 
that appear within the section 4.1.4 equation for NE. For 
heating performance, such direction already exists within the section 
on calculating the HSPF for a variable-speed heat pump, with regard to 
the source of the minimum speed quantities at 35 [deg]F.
    This change does not affect the calculated SEER. The revised text 
is found following the equation for NE in section 4.1.4 of 
Appendix M.

H. Using the Default or Tested Value of Cyclic-Degradation Coefficient

    Carrier asked if the manufacturer elects to run the optional tests, 
and the resulting CD exceeds the 0.25 default value, is the 
manufacturer obligated to use the tested value. (Public Hearing Tr., p. 
31) The current test procedure addresses this scenario for most cases 
where a CD is used in the SEER and HSPF calculations. 
Specifically, sections 4.1.1, 4.1.2.1, 4.1.3.1, 4.1.4.1, 4.2.1, and 
4.2.3.1, direct that if the optional test(s) are not conducted, the 
cooling (heating) cyclic-degradation coefficient, 
CDc (CDh), is to be set to 
the default value of 0.25. If the optional test(s) are conducted, 
CDc (CDh) must to be set to 
the lower of: the value calculated per the test or the default value of 
0.25. In response to Carrier's comment, DOE has added similar wording 
to sections 4.1.3.3 and 4.2.3.3, the only sections that did not include 
the clarifying language found in the sections referenced above.
    Furthermore, in reviewing the organization of the current test 
procedure while considering this update, DOE found that the information 
would be better placed in the earlier sections (within section 3) with 
the instructions as to which tests to conduct based on the type of 
equipment (i.e.,

[[Page 59913]]

single-speed, two-capacity, variable-speed, etc). Therefore, language 
has been added in the test procedure to clarify that if the tested 
cyclic-degradation coefficient is higher than the default value, the 
default value is to be used to calculate SEER and HSPF. (see sections 
3.2.1, 3.2.2.1, 3.2.3, 3.2.4, 3.5.3, 3.6.1, 3.6.2, 3.6.3, 3.6.4, 3.8.1, 
4.1.3.3, and 4.2.3.3).

I. Guidance on the Inclusion of Pre-Production Units in the Sample 
Population

    As part of the July 2006 proposed rule, DOE proposed that only pre-
production units fabricated using the same tooling used for the 
eventual full-production units could be used as part of the tested 
sample population to obtain the certified ratings of full-production 
units.
    ARI, Nordyne, and Carrier commented that the proposed wording is 
too narrow, and recommended that the current regulatory language not be 
changed. (ARI, No. 21 at p. 4; Nordyne, No. 19 at p. 3; Carrier, No. 17 
at p. 2) ARI and Trane explained that the tooling used for pre-
production units is often different than that used for production 
units. (Public Hearing Tr., pp. 192-193) Trane stated that pre-
production units must have the same configuration as the production 
unit to be included in the sample population, while Carrier suggested 
using wording such as that in the ARI Certification Program Operational 
Manual to define the configuration (e.g., same compressor, same air 
flow, etc.). (Public Hearing Tr., pp. 192, 198-199) Rheem commented 
that the ARI internal process handles ratings derived from pre-
production units by making the model subject to certification testing 
immediately after production starts. (Public Hearing Tr., p. 202)
    DOE agrees that the proposed criterion is too narrow, and that 
different tooling can yield equivalent machinery. Moreover, DOE 
believes that spot checks conducted under an industry certification 
program, such as the ARI Certification Program, provide a safeguard 
against the performance of the production unit deviating appreciably 
from ratings derived from testing pre-production units. For these 
reasons, DOE is not amending the existing requirements and will 
continue to allow manufacturers to test pre-production units.

J. Clarification of the Sample Population Used To Validate the Rated 
Seasonal Energy Efficiency Ratio and Heating Seasonal Performance 
Factor of Heat Pumps

    DOE proposed that a manufacturer must include the cooling and 
heating results from each heat pump of the sample population when 
obtaining the certified SEER and HSPF ratings. This requirement 
disallows testing multiple heat pumps and then using a subset of 
results for assigning the certified SEER rating and a different subset 
of results for determining the certified HSPF rating. The proposal 
provided one exception, which would allow additional testing in just 
one mode, cooling or heating, if the manufacturer elected to 
discontinue testing in the other mode at some point in the sample 
sequence.
    ACEEE, Nordyne, and Carrier supported the intent of clarifying the 
sample population used for determining heat pump ratings. (ACEEE, No. 
16 at p. 5; Nordyne, No. 19 at p. 3; Carrier, No. 17 at p. 2) Carrier 
and the ACEEE, however, recommended deleting the exception, noting that 
additional testing is insignificant as compared to the potential for 
misrepresented ratings. (Carrier, No. 17 at p. 2; ACEEE, No. 16 at p. 
5)
    DOE is aware of the testing burden on manufacturers, but agrees 
with Carrier and the ACEEE that this particular attempt at marginally 
reducing the test burden is not worthwhile. Thus, today's final rule 
adopts the proposal that all units of the sample population must be 
tested in both the cooling and heating modes and the results used for 
determining the heat pump's certified SEER and HSPF ratings without 
adopting the proposed exception for additional testing.

K. Clarification of the Definition of a ``Highest-Sales-Volume 
Combination''

    DOE proposed amendments to the definition of the Highest-Sales-
Volume Combination (HSVC) to require that a single-speed, split-system 
air conditioner must include the coil-only indoor unit likely to have 
the largest volume of retail sales with the particular model of outdoor 
unit. Proposed 10 CFR 430.24(m)(2). In addition, DOE proposed 
exceptions to this requirement to provide for equipment designed 
exclusively for blower-coil installations: mini-splits; multi-splits; 
small-duct, high-velocity systems; through-the-wall units; and 
condensing units having features (e.g., proprietary interfaces) that 
prevent their installation with third-party, coil-only indoor units. 
This proposal was made in recognition that coil-only units represent 
the overwhelming majority of installations of central air conditioners 
and, as such, the highest-sales-volume should reflect standard 
practice. The proposal also minimizes instances where the highest-sales 
volume combination of a split-system air conditioner could be defined 
as one with a ``blower-coil'' in order to meet Federal minimum energy 
efficiency standards and then have the outdoor unit combined with coil-
only indoor units where the combination would not meet the Federal 
energy efficiency standards.
    ACEEE, Carrier and ARI agreed that some clarification to the test 
procedure was needed in order to avoid such situations. (ACEEE, No. 16 
at p. 5; ARI, No. 21 at p. 4; Public Hearing Tr., pp. 208-209) ACEEE 
supported the goal of not having outdoor units installed with coil-only 
indoor units where the combination does not meet the energy efficiency 
standard. (ACEEE, No. 16 at p. 5) Instead of the proposed text, ARI and 
Carrier recommended that DOE adopt the wording from the 2006 ARI 
Certification Program Operational Manual for Unitary Air Conditioners & 
Air-Source Unitary Heat Pumps (Rated Below 65,000 Btu/h Cooling). (ARI, 
No. 21 at p. 4; Public Hearing Tr., pp. 208-209) Carrier and ARI 
commented that the proposed exception for outdoor units that prevent 
installations with coil-only units with a proprietary interface should 
be eliminated because it is not enforceable. Nordyne strongly objected 
to the entire proposal, stating that it restricts a manufacturer's use 
of technology. (Nordyne, No. 19 at pp. 3-4) Moreover, to implement such 
a change, Nordyne asserted that DOE needs to analyze the impact of 
minimally compliant units. Nordyne, however, did note its support for 
the proposed exception for blower coils having a proprietary interface.
    ARI and Carrier recommended the following alternative text to the 
July 2006 proposed rule:

HSVTC, Highest-sales-volume Tested Combination. For Unitary Air-
Conditioners below 14 SEER, the HSVTC must be an RCU-A-C 
combination, except for through-the-wall and ductless equipment 
(RCU-A-CBO). For Unitary Air-Conditioners 14 SEER and above, every 
outdoor model number must have a coil-only rating. Coil-only ratings 
offered for sale must be publicly viewable. Coil-only ratings not 
offered for sale are viewable only to ARI staff. Non-viewable 
ratings fall under all compliance guidelines except the challenge 
procedure. If a non-publicly viewable rating falls below NAECA 
minimum, then the manufacturer must submit a coil-only rating that 
meets NAECA minimum and is verified through ARI testing.

[[Page 59914]]

Until then, the Basic Model Group ratings will not be listed in the 
ARI directory.

    Historically, the highest sales volume combination for most split-
system air conditioners has had a coil-only indoor unit. Both the June 
2006 proposed rule and the ARI alternative maintain this historical 
practice. DOE, however, believes ARI's approach is arbitrary and 
results in uncertainties to manufacturers. Furthermore, DOE believes it 
would be difficult to implement the above ARI algorithm. With the ARI 
approach, the manufacturer may have to re-test in a coil-only 
configuration after having tested in a blower-coil configuration, if 
the expected SEER of 14 or higher is not realized in laboratory 
testing. In addition, if DOE were to adopt the ARI alternative and the 
minimum energy efficiency standards were amended, DOE would have to 
modify the requirement, since the new minimum could be higher than the 
14 SEER requirement in the ARI alternative. Conversely, in formulating 
the approach proposed in the July 2006 proposed rulemaking, DOE first 
considered requiring that all split-system air conditioners be tested 
with a coil-only indoor unit. DOE recognized, however, that in addition 
to the exceptions such as equipment designed exclusively for blower-
coil installations, other exceptions would have to be recognized. These 
other exceptions include two-capacity and variable-speed units, because 
they are always much more efficient than 14 SEER, and do not risk 
having a coil-only combination that would not meet the DOE efficiency 
standards. Therefore, DOE applied the coil-only requirement only to 
split system air conditioners having a single-speed compressor.
    Returning to the issue of listed exceptions, DOE agrees with ARI 
and Carrier that the proposed exception for combinations that prevent 
applications with third-party coil-only indoor units would be 
prohibitively difficult to define, verify, and enforce. DOE believes 
that its proposal to substitute the words ``mini-splits'' and ``multi-
splits'' for ``ductless equipment,'' is somewhat more comprehensive 
because it includes ducted multi-split systems. Finally, SDHV 
manufacturers, at present, only manufacture indoor coils and do not 
manufacture outdoor units. Since SDHV manufacturers do not offer for 
sale complete systems, they are not subject to specifying HSVC's. Thus, 
SDHV systems do not need to be included as an exception.
    As to Nordyne's objections, DOE stands by its position as stated in 
the July 2006 proposed rule. DOE believes that its proposal, which is 
adopted in today's final rule, increases the likelihood tha