[Federal Register Volume 61, Number 69 (Tuesday, April 9, 1996)]
[Proposed Rules]
[Pages 15735-15738]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-8782]


[[Page 15736]]


10 CFR Part 437

Office of Energy Efficiency and Renewable
[Docket No. EE-RM-95-202]
RIN 1904-AA74

Home Energy Rating System Guidelines

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 

ACTION: Proposed rule; Notice of limited reopening of the comment 


SUMMARY: On July 25, 1995, the Department of Energy (DOE) published a 
notice of proposed rulemaking to establish voluntary guidelines for 
home energy rating systems that provide residential building energy 
efficiency ratings and were developed in consultation with the Home 
Energy Rating Systems Council. The purpose of this document is to 
reopen the comment period for 30 days in order to solicit 
recommendations from the Board of Directors of the Home Energy Rating 
Systems Council, and comments from all interested persons, with respect 
to new policy options and technical data that DOE is considering in 
preparation for final guidelines. These options respond to comments 
concerning three components of the guidelines: air infiltration levels 
for the reference and the rated home; heating, air conditioning and hot 
water equipment for the reference home; and the phased-in compliance 

DATES: Written comments ([10] copies) on the issues presented in this 
document must be received on or before May 9, 1996.

ADDRESSES: Comments should be addressed to: U.S. Department of Energy, 
Office of Energy Efficiency and Renewable Energy, EE-33, Docket No. EE-
RM-95-202, 1000 Independence Avenue, S.W., Washington, D.C. 20585, 202-
    Public Reading Room: Supporting information used to develop this 
notice and the written comments received are contained in the Public 
Rulemaking File, Docket No. EE-RM-95-202. This Docket is available for 
examination in DOE's Freedom of Information Reading Room. 1E-090, 
Forrestal Building, 1000 Independence Avenue SW., Washington, D.C. 
20585, 202-586-6020, between 9 a.m. and 4 p.m., Monday through Friday, 
except Federal holidays. The supporting information used to develop 
this notice is also available on the internet at URL#: http://
www.eren.doe.gov or from the Energy Efficiency and Renewable Energy 
Clearinghouse at 1-800-DOE-EREC (1-800-363-3732).
John Reese or Robert Mackie, Buildings Division, EE-432, U. S. 
Department of Energy, Room 1J-018, 1000 Independence Avenue SW., 
Washington, D.C. 20585, (202) 586-7819.
Diana Dean, Office of General Counsel, GC-12, U.S. Department of 
Energy, Room 6B-231, 1000 Independence Avenue SW., Washington, D.C. 
20585, (202) 586-7440.


I. Introduction

    This notice to reopen the comment period is part of an ongoing, 
Congressionally mandated rulemaking to establish voluntary home energy 
rating system guidelines that are required by section 271 of the 
National Energy Conservation Policy Act (Act), as amended by the Energy 
Policy Act of 1992. 42 U.S.C. 8236. The background for this rulemaking 
is discussed in detail in the Supplementary Information section of the 
notice of proposed rulemaking. 60 FR 37949 (July 25, 1995).
    Since the close of the 60-day comment period on the notice of 
proposed rulemaking, DOE has been reviewing the comments. As directed 
by the Act, DOE has consulted with the Home Energy Rating Systems 
(HERS) Council and sought its views on issues that emerged from the 
comments. With respect to comments claiming that the proposed reference 
home infiltration rate is too high and that the proposed reference home 
heating, air conditioning and hot water equipment produced unexpected 
rating anomalies, the Technical Committee of the HERS Council made 
recommendations that are discussed in detail later in this notice. The 
HERS Council Board did not take a position on these recommendations and 
sent these issues back to the Technical Committee for further review.
    Consistent with its obligation to promulgate final guidelines, DOE 
has independently reviewed the HERS Technical Committee's 
recommendations, and today makes available for public comment DOE's 
technical evaluations. These evaluations are entitled ``Climate 
Sensitive Air Change Rate Study'' and ``Analysis of Heating, Air 
Conditioning, and Water Heating Equipment Adjustment Factors.'' They 
have been added to the public file in DOE's Freedom of Information 
Reading Room and may be obtained from the information contact for this 
rulemaking or through the internet as described above. DOE is now 
considering whether to modify the proposed guidelines accordingly.
    In addition, adverse comments on the advisability of DOE's proposed 
distinction between ``basic compliance'' and ``full compliance'' for 
the two years following promulgation of the guidelines have prompted 
DOE to consider an alternative approach to phasing in compliance that 
was not discussed in the notice of proposed rulemaking. Later in this 
notice, DOE's tentative approach to resolving these issues is set forth 
for public comment.
    DOE requests that the HERS Council Board respond to this notice by 
filing comments that include recommendations regarding the policy 
options DOE is considering. DOE also would welcome the comments of 
other interested members of the public.

II. Discussion of New Policy Options

A. Infiltration

    DOE originally proposed guidelines assuming a level of 0.67 air 
changes per hour (ACH) for the reference home to which the subject 
rated home is compared. The 0.67 ACH was based on the Council of 
American Building Official's Model Energy Code (MEC), 1994 amendments.
    Although one comment endorsed the proposed level, most comments 
were critical. There were two major concerns. One was that the proposed 
0.67 ACH results in a reference home that is too energy inefficient 
when compared to newly constructed houses that typically have 
infiltration rates below 0.50 ACH. Another concern was that a single 
national air change rate was not valid for all climate conditions.
    Some of the critics suggested substituting a 0.50 ACH level 
provided for in the 1995 MEC. Others favored reliance on the 
infiltration and ventilation consensus standards of the American 
Society of Heating, Refrigerating, and Air-Conditioning Engineers 
(ASHRAE): ASHRAE Standard 119-1988 establishes minimum air leakage 
levels and provides a method for establishing a normalized leakage 
area, producing a consistent measure of building tightness; ASHRAE 
Standard 136-1993 establishes a calculation method for effective air 
change and provides weather factors that, when applied to a normalized 
leakage area, produce an effective air change rate for various 
locations across the country; and

[[Page 15737]]
ASHRAE Standard 62-1989 sets minimum standards for ventilation.
    The HERS Council Technical Committee supported use of the ASHRAE 
standards. They suggested that the guidelines should provide a base 
level value for the normalized leakage area of 0.57 to be adjusted for 
weather using the ASHRAE factors. The 0.57 normalized leakage area base 
level increases the reference home's energy efficiency (in comparison 
to the level under the proposed guidelines), yielding a level 
appropriate for most regions when adjusted for weather conditions. For 
the vast majority of the sites, the reference home would be between 
0.57 ACH and 0.40 ACH. Furthermore, with a 0.57 normalized leakage, the 
Technical Committee believed that no weather adjusted air change rates 
would fall below the 0.35 ACH minimum ventilation rate set by ASHRAE 
Standard 62.
    The suggestion to use the single point set by the Model Energy Code 
overlooked an important shortcoming. This approach, is not sensitive to 
the variation in air change rates due to climatic variations. DOE has 
decided that, with two minor modifications, the Technical Committee's 
recommendation to use ASHRAE standards has sufficient merit to be 
considered for inclusion in the final guidelines. The first 
modification is to incorporate in the guidelines the minimum 0.35 ACH 
for the reference house. This is necessary because two of the 213 sites 
nationwide examined by the Technical Committee are in fact slightly 
below the 0.35 level. The second modification is a conforming change to 
the treatment of the rated house. That change would involve adjustment 
of the ACH using the weather factors in ASHRAE Standard 136-1993. 
Addition of this approach to the proposed guidelines may provide a 
nationally recognized method for setting air change rates sensitive to 
different climate conditions and consistent with recommended minimum 
ventilation rates.
    DOE also solicits comment on establishing a minimum allowable air 
change rate. DOE is now considering as a policy option for the final 
guidelines setting 0.35 ACH as the minimum allowable air change rate on 
which energy savings may be calculated for the rated home. The 0.35 ACH 
coincides with the rate currently specified by ASHRAE Standard 62 for 
minimum ventilation. Lowering the level of the air change rate any 
further should not result in a higher HERS rating.

B. Heating, Air Conditioning, and Hot Water Equipment

    The proposed guidelines provided for a computerized comparison of 
the rated home to a reference home using the same energy source as the 
rated home. Consistent with the recommendations of the HERS Council 
Board, the proposed guidelines further provide for estimated energy 
consumption at the home for the rated and reference homes.
    After the comment period ended, the HERS Technical Committee 
identified some anomalous rating results that the foregoing approach 
produced when it was assumed that an identical energy efficiency 
improvement (e.g., a new air conditioning system) was made to two rated 
homes. These two rated homes differ only in the fuel used for heating, 
air conditioning, and hot water. Improvements to fossil fuel homes 
tended to rate higher than electric homes in climates with large 
heating loads. The relationship reversed for climates with large 
cooling loads.
    The problem occurs because the end use loads of the reference and 
rated homes are divided by the seasonal performance coefficients of the 
heating, cooling, and hot water equipment to arrive at the consumption. 
The impact of other efficiency changes is then based on energy 
consumption. Consequently, the same improvements have different impacts 
in homes of different fuels.
    To achieve an equal treatment of efficiency improvements, the HERS 
Technical Committee recommended that an adjustment factor be used. This 
factor would adjust the consumption of the reference and rated homes 
for the purposes of the rating point score. It normalizes load so that 
efficiency improvements can be measured equally regardless of fuel 
type. This is achieved by setting one profile of equipment as the basis 
from which equipment utilizing other fuels is specified. The base fuel 
could be any fuel. The Technical Committee selected a profile of 
electric equipment as the basis because it is widely available for 
heating, cooling, and hot water purposes. Fossil fuel cooling systems, 
for example, are much less common.
    The HERS Council had originally developed a table of efficiencies 
for heating, cooling, and hot water equipment and included them in 
their guidelines. This information was incorporated in section 437.103, 
Tables 2 and 4, of the proposed guidelines and served as the basis for 
efficiency of equipment in the reference home. Rather than using those 
tables as the basis for developing the adjustment factor, the Technical 
Committee reduced the tables by combining classes and sizes of 
equipment. Because Table 2 did not include a minimum efficiency level 
for biomass heating or gas cooling, the Technical Committee used 
professional judgement to set levels for these technologies.
    DOE has reviewed the HERS Council Technical Committee's 
recommendations and believes they may have merit. However, reducing, 
the information in Tables 2 and 4 to the extent recommended 
oversimplifies the range of equipment options. Therefore, additional 
equipment options from Tables 2 and 4 are presented below with the 
adjustment factors and the accompanying equation. Table 2A presents 
factors for gas cooling and biomass heating. DOE is particularly 
interested in comments on these two values for which no standards 

                                                     Table 2                                                    
                       Type                                       Units                    Rating     factor \1\
Heating equipment:                                                                                              
    Gas or Oil Warm Air Furnace..................  AFUE                                        0.78         0.39
    Gas Boiler (water)...........................  AFUE                                         .80          .40
    Gas Boiler (steam)...........................  AFUE                                         .75          .37
    Oil Boiler (water or steam)..................  AFUE                                         .80          .40
    Electric Air Source Heat Pump................  HSPF                                        6.80         1.00
Cooling equipment:                                                                                              
    Electric Central Air Conditioner.............  SEER                                       10.00         1.00
    Heat Pump....................................  SEER                                       10.00         1.00

[[Page 15738]]

    1. The adjustment factor is created by dividing the seasonal 
performance coefficient of the alternative fuel device (eg. natural 
gas, fuel oil, biomass, etc.) by the seasonal performance coefficient 
of the equivalent electric device. The seasonal performance 
coefficients for electric heating and cooling devices have units of 
Btu/W. To convert HSPF and SEER to seasonal performance coefficients 
they must be divided by 3.413 Btu/W, yielding seasonal performance 
coefficients of 1.99 and 2.93 for the standard HSPF of 6.80 and SEER of 
10.0, respectively. For water heaters, EF is used for all fuel types. 
EF and AFUE are already unitless seasonal performance coefficients, so 
they do not require any modification.

Gas Cooling......................................  N/A \2\                                     0.75         0.26
Biomass Heating..................................  N/A                                          .70          .35

    2. No standard efficiencies exist for these technologies. The HERS 
Technical Committee recommended these levels for consideration.

                                                                         Table 4                                                                        
                  Water heating                                           Rated storage capacity (gallons) and adjustment factor                        
                                                          30 gallon                 40 gallon                 50 gallon                 60 gallon       
                      Type                       -------------------------------------------------------------------------------------------------------
                                                       EF           AF           EF           AF           EF           AF           EF           AF    
Gas.............................................         0.56         0.61         0.54         0.60         0.53         0.60         0.51         0.59
Oil.............................................          .53          .58          .53          .59          .50          .57          .48          .55
Electric........................................          .91         1.00          .90         1.00         0.88         1.00         0.87         1.00
EF = Energy Factor. AF = Adjustment Factor.                                                                                                             

    The adjustment factors in the Tables 2, 2A and 4 are used in the 
ER=((EH  x  EUH + EC  x  EUC + EW  x  
EUW) + EM)
ER=Adjusted energy consumption for point calculation.
EH = Rated home estimated energy purchased for heating.
EC = Rated home estimated energy purchased for cooling.
EW = Rated home estimated energy purchased for water heating.
EUH,C,W = Equipment utilization factors from Tables 2, 2A & 4

    The point score is then determined using the following equation:
Point score = 100-((ER/EC)/.05)
ER=Estimated purchased energy consumption for heating, cooling, and 
water heating of rated home (Btu).
EC=Estimated purchased energy consumption for heating, cooling, and 
water heating of reference home (Btu).

    DOE has performed an analysis of the HERS Technical Committee 
recommendations. A copy of that analysis has been placed in the public 
rulemaking file and is available upon request or through the internet. 
The analysis shows that the reduction in consumption by the same 
efficiency improvements, in homes of different fuels, can vary by 3% to 
4%. This difference can benefit electric homes or fossil fuel homes. 
The adjustment factor is shown to eliminate this variation.
    On the basis of this analysis, DOE is considering adopting the HERS 
Technical Committee recommendations with the modifications described 
above. Interested members of the public, including the HERS Council 
Board, are invited to comment on the analysis as well as the general 
suitability of the recommendations.

C. Phased-in Compliance Period

    The proposed guidelines allow for phased-in compliance over a two 
year period. HERS providers would have one year to come into ``basic 
compliance'' by meeting a specific set of guideline provisions, and two 
years to come into ``full accreditation'' by meeting all the guideline 
    This provision generated a wide range of comments. Some advised the 
total elimination of the section. One argued for an additional one year 
grace period for meeting the ``basic compliance'' level. The two level 
approach was criticized by those who felt that allowing an intermediate 
level would undermine the value of ``full accreditation.''
    DOE thinks that accreditation is a legitimate subject to address in 
the guidelines and that failure to include suitable non-binding 
guidance would irresponsibly leave a crucial implementation subject 
uncovered. The comments revealed that nearly all HERS providers would 
have to make adjustments and lending institutions have indicated that 
they are willing to deal with applicants on an individual basis during 
an interim period before full compliance is required. Therefore, DOE is 
considering modifying the proposed guidelines by eliminating the 
``basic compliance'' level and allowing two years for development of 
accrediting procedures and for HERS providers to meet all components 
and become accredited under the guidelines. DOE invites, particularly 
financial institutions, to comment on this possible policy.

    Issued in Washington, D.C. on April 3, 1996.
Christine A. Ervin,
Assistant Secretary, Energy Efficiency and Renewable Energy.
[FR Doc. 96-8782 Filed 4-8-96; 8:45 am]