`[Federal Register Volume 63, Number 90 (Monday, May 11, 1998)]
[Rules and Regulations]
[Pages 25996-26016]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-12296]



[[Page 25995]]

_______________________________________________________________________

Part III





Department of Energy





_______________________________________________________________________



Office of Energy Efficiency and Renewable Energy



_______________________________________________________________________



10 CFR Part 430



Energy Conservation Program for Consumer Products: Test Procedure for 
Water Heaters; Final Rule

  Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and 
Regulations  

[[Page 25996]]



DEPARTMENT OF ENERGY

Office of Energy Efficiency and Renewable Energy

10 CFR Part 430

[Docket No. EE-RM-94-230]
RIN 1904-AA52


Energy Conservation Program for Consumer Products: Test Procedure 
for Water Heaters

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

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The Department of Energy (DOE or the Department) is amending 
its test procedure for water heaters. The first-hour rating for 
storage-type water heaters is revised to more accurately measure large 
storage-type water heaters. Also, electric and gas-fired instantaneous 
water heaters are rated at the maximum flow rate to distinguish them 
from storage-type water heaters.

EFFECTIVE DATE: This rule is effective June 10, 1998.

FOR FURTHER INFORMATION CONTACT: Terry Logee, U.S. Department of 
Energy, Energy Efficiency and Renewable Energy, Mail Station EE-43, 
Forrestal Building, 1000 Independence Avenue, S.W., Washington, D.C. 
20585-0121, Telephone (202) 586-1689, FAX (202) 586-4617, 
[email protected].
    Eugene Margolis, Esq., U.S. Department of Energy, Office of General 
Counsel, Mail Station GC-72, Forrestal Building, 1000 Independence 
Avenue, S.W., Washington, D.C. 20585-0103, Telephone (202) 586-9507, 
FAX (202) 586-4116, [email protected].

SUPPLEMENTARY INFORMATION:

I. Introduction
    A. Authority
    B. Background
II. Discussion of Comments
    A. General Comments
    B. Product Specific Comments
    1. Instantaneous Water Heaters
    2. Storage-type Water Heaters with Rated Storage Capacities Less 
than 20 Gallons
    3. Definitions
    4. Heat Pump Water Heaters
    5. First-Hour Rating for Storage-type Water Heaters
    6. Installation of Under-the-Counter and Counter-Top Water 
Heaters
    7. Test Conditions
    8. Cost-Based Correction Factor for Fossil-Fueled Residential 
Appliances
III. Procedural Requirements
    A. Review Under the National Environmental Policy Act of 1969
    B. Review Under Executive Order 12866, ``Regulatory Planning and 
Review''
    C. Review Under the Regulatory Flexibility Act of 1980
    D. ``Takings'' Assessment Review
    E. Federalism Review
    F. Review Under the Paperwork Reduction Act
    G. Review Under Executive Order 12988, ``Civil Justice Reform''
    H. Review Under the Unfunded Mandates Reform Act of 1995
    I. Congressional Notification

I. Introduction

A. Authority

    Part B of Title III of the Energy Policy and Conservation Act, as 
amended (EPCA or the Act), establishes the Energy Conservation Program 
for Consumer Products other than Automobiles (Program).1 The 
products currently subject to this Program include water heaters, which 
are the subject of today's Final Rule.
---------------------------------------------------------------------------

    \1\ Part B of Title III of Energy Policy and Conservation Act, 
as amended, is referred to in this Final Rule as ``EPCA'' or the 
``Act.'' Part B of Title III is codified at 42 U.S.C. 6291-6309.
---------------------------------------------------------------------------

    Under the Act, the Program consists essentially of three parts: 
testing, labeling, and the Federal energy conservation standards. The 
Department, in consultation with the National Institute of Standards 
and Technology (formerly the National Bureau of Standards), is required 
to amend or establish test procedures as appropriate for each of the 
covered products. Section 323 of EPCA, 42 U.S.C. 6293. The purpose of 
the test procedures is to produce test results that 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. Section 
323(b)(3) of EPCA, 42 U.S.C. 6293(b)(3).
    Beginning 180 days after a test procedure for a 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 products, except as reflected in tests 
conducted according to the DOE procedure. Section 323(c)(2) of EPCA, 42 
U.S.C. 6293(c)(2).
    Furthermore, DOE is required to determine to what extent, if any, 
an amended test procedure would alter the measured energy efficiency or 
measured energy use of any covered product as determined under the 
existing test procedure. Section 323(e)(1) of EPCA, 42 U.S.C. 
6293(e)(1).

B. Background

    Today's Final Rule amends DOE's test procedure for water heaters by 
revising the method used to determine the first-hour rating of storage-
type water heaters, adding a new rating for electric and gas-fired 
instantaneous water heaters, and amending the definition of a heat pump 
water heater.
    On March 23, 1995, DOE published in the Federal Register (60 FR 
15330) a Notice of Proposed Rule and Public Hearing on proposed 
amendments to clarify the water heater test procedure and requested 
data, comments, and information regarding its applicability and 
workability. The Department conducted a public hearing on July 12, 
1995, and a public workshop on February 12, 1997, and requested written 
comments.
    The proposed amendments to the water heater test procedure included 
revisions to make the water heater test procedure applicable to 
electric and oil-fired instantaneous water heaters; coverage for 
testing storage-type water heaters with rated storage capacities less 
than 20 gallons (76 liters); revision of the first-hour rating for 
storage-type water heaters; amendment to the current definition for 
heat pump water heater; and the addition of new definitions for heat 
pump water heater storage tank, add-on heat pump water heater, integral 
heat pump water heater, and solar water heater. In addition, DOE 
requested comments on the adequacy of the test procedure for heat pump 
water heaters regarding the use of a backup electric resistance 
element(s).

II. Discussion of Comments

A. General Comments

    Forty commenters submitted written comments in response to the 
proposed rulemaking on water heaters. After reviewing these comments 
and the comments presented during the public hearing, the Department 
held a public workshop on February 12, 1997, to solicit additional 
comments on the issues in the Proposed Rule. Workshop topics included 
the daily hot water consumption of 64.3 gallons (243.4 liters) and the 
thermostat setting of 135 deg.F (57.2 deg.C) in the existing test 
procedure. The notice for the public workshop was published in the 
Federal Register (62 FR 4202, January 29, 1997). Nine commenters 
submitted written comments prior to and after the workshop. Those 
written comments received prior to the workshop (from the Gas Appliance 
Manufacturers Association [GAMA], February 12, 1997, Water Heater Test 
Procedure Workshop Transcript [hereafter referred to as ``February 1997 
Transcript''] at Appendix I; Electric Power Research Institute [EPRI], 
February 1997 Transcript at Appendices E and J; and Controlled Energy 
Corp. [CEC], February

[[Page 25997]]

1997 Transcript at Appendix H) were distributed to all participants at 
the beginning of the workshop for inclusion in the workshop session. 
During the rulemaking process, a number of commenters stated their 
support of the EPRI recommendations on all issues. These commenters 
included: Northeast Utilities Service Co., No. 11; The Dayton Power & 
Light Co., No. 15; Utilities District of Western Indiana, No. 16; 
National Rural Electric Coop. Assoc., No. 18; Decatur County REMC, No. 
19; Pennsylvania Power & Light Co., No. 20; Central and South West 
Services, Inc., No. 21; Centerior Energy, No. 22; Hawaiian Electric 
Co., No. 23; Southern Company Services, Inc., No. 24; Potomac Electric 
Power Co., No. 26; East Kentucky Power Cooperative, Inc., No. 34; Ohio 
Edison Co., No. 39; Southern California Edison Co., No. 43; Duke Power 
Co., No. 44; and Nevada Power Co., No. 45.
    The following is a summary of the public comments, presented during 
and after both the public hearing and the workshop, on each of the DOE 
proposed amendments/revisions, and on other issues concerning the 
existing test procedure.
    On October 31, 1997, the comment period was reopened on the issues 
of the maximum gallons (liters) per minute rating for electric and gas-
fired instantaneous water heaters and the energy factor of the heat 
pump water heater storage tank. (62 FR 58923, October 31, 1997.)

B. Product Specific Comments

1. Instantaneous Water Heaters
    a. Coverage of Electric and Oil-Fired Instantaneous Water Heaters. 
The current test procedure does not address the testing of electric and 
oil-fired instantaneous water heaters, because they are not defined in 
the test procedure. In the 1995 proposed rulemaking for water heaters, 
DOE proposed definitions for these two types of instantaneous water 
heaters so they would be subject to the same test procedures as gas-
fired instantaneous water heaters (i.e., the first-hour rating test and 
the 24-hour simulated use test).
    GAMA agreed that electric and oil-fired instantaneous water heaters 
should be covered in the test procedures. However, GAMA said it is 
unaware of any residential oil-fired instantaneous models on the 
market. (GAMA, No. 1 at 2 and February 1997 Transcript at 119.) Edison 
Electric Institute (EEI), Bock Water Heaters (Bock), the Federal Trade 
Commission (FTC), and the Oregon Energy Office (Oregon) also stated 
that they know of no residential oil-fired instantaneous water heaters 
on the market. (EEI, February 1997 Transcript at 119; Bock, February 
1997 Transcript at 120; FTC, February 1997 Transcript at 120; and 
Oregon, No. 51 at 3.) In response to the reopening notice of October 
1997, Controlled Energy Corporation provided information on a kerosene-
fired instantaneous water heater sold by Monitor Products, Inc. (CEC, 
No. 64 at 1.) The California Energy Commission (CAEC) also provided 
information on one oil-fired instantaneous water heater manufactured by 
Monitor Products of Princeton, NJ, which meets the definition in the 
test procedure for the input BTU rating. The CAEC also informed DOE 
that Monitor intends to introduce another smaller instantaneous water 
heater soon, and the CAEC opposed the DOE withdrawing coverage for oil-
fired instantaneous water heaters. (CAEC, No. 68 at 1-2.)
    Virginia Power stated that it does not support the testing and 
rating of electric units because of the small variance in efficiency 
among them. Virginia Power stated that electric units are not typically 
compared to oil or gas-fired instantaneous water heaters. Virginia 
Power claimed the incomparability is due to the difference in 
utilization between gas-fired and electric instantaneous water heaters. 
(Virginia Power, No. 50 at 2 and No. 66 at 3.) The Department 
interprets this statement to mean that gas-fired models are for whole-
house applications, whereas electric models are for point-of-use 
applications such as kitchen or lavatory sinks.
    EPRI stated that neither the existing nor the proposed test should 
be applied to instantaneous water heaters because a heating rating of 
more than 150,000 Btu per hour is needed to satisfy whole-house 
applications and all instantaneous water heaters for residential use 
are below that heating capacity. EPRI claimed that an instantaneous 
water heater should not have an efficiency rating because the 
efficiency rating would falsely imply an equivalency with tank-type 
water heaters. (EPRI, No. 56 at 11.)
    The Oregon Energy Office suggested that an energy efficiency rating 
for instantaneous water heaters is needed, and suggested that a test 
procedure should be developed that would take into account the warm-up 
and cool-down losses during a draw for all units (as well as the flue 
and pilot light losses for gas-fired units). Oregon stated that the 
procedure for instantaneous water heaters should not be the same as for 
storage-type water heaters. (Oregon, No. 51 at 3.)
    GAMA claimed for electric models that there are distinctions 
between larger models intended for multiple points of use and smaller 
models intended for a single point of use. GAMA suggested that DOE may 
need to make distinctions between such units by creating separate 
classes of instantaneous water heaters. (GAMA, No. 1 at 2.)
    DOE believes that separate classes of electric instantaneous water 
heaters would require technical data on these models, such as: (1) The 
intended purpose of use; (2) the frequency of daily draws at the point 
of use; (3) the average volume of each draw; and (4) the average amount 
of the total daily draw. However, DOE believes that at the present 
time, the development of separate classes of electric instantaneous 
water heaters for residential application is not needed because, even 
at the proposed maximum input power rating of 12 kW (40,944 Btu/h), an 
electric instantaneous water heater can only supply a maximum of 1.06 
gallons per minute (gpm) (4.01 liters per minute [L/min]) of water at a 
77 deg.F (42.8 deg.C) temperature rise (from 58 deg.F to 135 deg.F 
[14.4 deg.C to 57.2 deg.C]) on a continuous draw basis. DOE believes 
this is far below the requirements of a whole-house application which 
could range from 3-5 gallons per minute. Furthermore, the limit on the 
input heating rate of electric instantaneous water heaters is not 
likely to change because it is limited by the current carrying capacity 
of wiring in most residential housing.
    Additionally, DOE believes that the variation of the energy 
efficiency of electric instantaneous water heaters would be small for 
similar sized models, provided they are tested under similar conditions 
because energy losses only occur during the warm-up and cool-down of 
the heaters between water draws. However, test data are needed to 
determine the magnitude of these losses, which are functions of the 
water used during each draw and the frequency of draws. No field data 
is available on the average draw rate, amount per draw, and the average 
daily draw volumes for these small electric, point-of-use type 
instantaneous water heaters. The daily hot water usage of 64.3 gal 
(243.4 L) specified for whole-house application does not apply to these 
small heating capacity electric units. Consequently, the energy 
efficiency, and energy consumption cannot be determined for these units 
without additional data. Therefore, DOE will not test electric 
instantaneous water heaters for energy efficiency or energy consumption 
until a future rulemaking when the daily hot

[[Page 25998]]

water usage data for point-of-use instantaneous water heaters are 
available.
    DOE did not receive any indication until after the October 1997 
notice of reopening that residential oil-fired instantaneous water 
heaters are on the market. DOE's belief that these water heaters were 
not being sold in the United States was supported by GAMA, Bock, EEI, 
the FTC, and the Oregon Energy Office. DOE believes that there is not 
time for adequate public review and comment to include oil-fired 
instantaneous water heaters in this rulemaking. Accordingly, DOE 
withdraws its proposal to test oil-fired instantaneous water heaters in 
today's Final Rule.
    The Department will continue to require the testing of gas-fired 
instantaneous water heaters for energy efficiency and energy 
consumption because data is needed for the FTC labeling program.
    b. GPM v. First-Hour Rating. In the 1995 proposed rulemaking, DOE 
proposed testing for electric and oil-fired instantaneous water heaters 
based on the first-hour rating currently used for gas-fired 
instantaneous water heaters. This proposal would test instantaneous 
water heaters in a manner equal to gas-fired storage-type water 
heaters. On October 31, 1997, DOE reopened the comment period on first-
hour rating for instantaneous water heaters. In its reopening notice, 
DOE proposed to revise the first-hour rating for instantaneous water 
heaters from gallons per hour to a test that measures the maximum flow 
rate in gallons per minute (gpm) (liters per minute [L/min]) at a 
77 deg.F (42.8 deg.C) temperature rise. DOE proposed to call this 
rating the maximum gpm rating.
    DOE's proposed revision was in response to concerns raised by 
several commenters regarding the March 1995 proposed rule. EEI, EPRI 
and the Tennessee Valley Authority (TVA) considered the proposed first-
hour rating procedure for instantaneous water heaters to be 
inappropriate because it would lead consumers to ``mistakenly compare 
instantaneous and storage-type water heaters as being equivalent.'' 
They argued that a storage-type water heater can supply a large amount 
of hot water during a short draw period, whereas an instantaneous water 
heater may not be able to supply a similar amount of hot water because 
it is limited by its heating rate. (EEI, No. 2 at 5, No. 27 at 5, and 
July 12-13, 1995, Public Hearing Transcript [hereafter referred to as 
July 1995 Transcript] at 22 and 27; EPRI, No. 17 at 4; and TVA, No. 14 
at 2.)
    During the 1997 workshop and in its written comments, EPRI 
recommended a rating based on the maximum gpm flow rate at a 50 deg.F 
(27.8 deg.C) temperature rise if a single rating value is used, and at 
both a 50 deg.F and 77 deg.F temperature rise if two rating values are 
used. EPRI stated that it prefers a rating at both a 50 deg.F and 
77 deg.F temperature rise. (EPRI, No. 56 at 11.)
    GAMA supported EPRI's alternative of a maximum flow rate. However, 
GAMA's alternative test procedure involves adjusting the flow rate to 
obtain a temperature rise of 77 deg.F in the instantaneous water 
heater, and using this maximum gpm flow rate as the rating 
characteristic, rather than the current first-hour rating value. GAMA 
recommended that the temperature rise be the same as specified for 
storage-type water heaters--that is, 77 deg.F, not 50 deg.F as 
suggested by other commenters. (GAMA, No. 35 at 2.) GAMA stated it 
selected a temperature rise of 77 deg.F because hot water also will be 
used for machine-related applications (dishwashers and clothes washers) 
that require a 135 deg.F (57.2 deg.C) temperature. (GAMA, February 1997 
Transcript at 127 and 138.)
    Virginia Power supports the proposal to rate instantaneous water 
heaters with a maximum gpm rating. (Virginia Power, No. 42 at 2 and No. 
66 at 2-3.) However, Virginia Power supports dual maximum gpm ratings, 
at both 50-52 deg.F and 77 deg.F rise. Virginia Power stated that both 
temperature rises are used in applications (human-contact at 110 deg.F 
[43.3 deg.C] and machine use at 135 deg.F [57.2 deg.C]. Virginia 
further stated that DOE's statement in the October 1997 reopening 
notice that a 77 deg.F temperature rise will ensure that consumers in 
cold regions of the country will have an acceptable water temperature 
is inconsistent with the rationale used to establish other parameters 
of the test procedure (i.e., establishing on the basis of national 
average values). (Virginia Power, No. 50 at 2 and No. 66 at 3.) EEI 
supported Virginia's position on this issue. (EEI, No. 65 at 1.) Oregon 
stated that both a 50 deg.F and 77 deg.F would be useful in sizing a 
unit properly. (Oregon, No. 51 at 3.) State Industry claimed that a 
rating value based on a nominal temperature rise of 50 deg.F would not 
provide consumers with information on whether the heater is capable of 
delivering hot water at a 77 deg.F temperature rise. (State Industry, 
February 1997 Transcript at 134.)
    Based on the comments, DOE believes there is a consensus that the 
current first-hour rating for instantaneous water heaters may mislead 
consumers because it may overstate the capability of the instantaneous 
water heater to provide a given quantity of hot water at a given 
instant of time. The suggestion from GAMA, EEI, EPRI, and other 
commenters to replace the first-hour rating parameter with a maximum 
flow rate (gpm) over a specific temperature rise (77 deg.F [42.8 deg.C] 
or 50 deg.F [27.8 deg.C]) instead of a total volume flow over one hour 
is reasonable. This comparison measures the ability of instantaneous 
water heaters to deliver the maximum possible amount of hot water to 
the user at a specific temperature rise occurring any single moment. 
Because some consumer appliances require a hot water temperature in the 
135-140 deg.F (57.2-60 deg.C) range, information on the amount of flow 
at a 77 deg.F rise is needed. Also, a rating value based on a nominal 
temperature rise of 50 deg.F would not provide consumers with 
information on whether the heater is capable of delivering hot water at 
135 deg.F. Therefore, DOE believes that the maximum flow rate at the 
rated energy input rate and at a temperature rise of 77 deg.F across 
the water heater should be specified for rating the capability of 
instantaneous water heaters to deliver hot water. Furthermore, this 
maximum flow rate should be specified in place of the first-hour 
rating. The Department is therefore creating a new rating for 
instantaneous gas and electric water heaters using a ``maximum gpm draw 
rate at 77 deg.F rise'' criterion, and renaming the criterion from 
``First-Hour Rating'' to ``Maximum GPM Draw Rating'' in Sections 5.2 
and 6.2 of today's Final Rule.
    c. Water Temperature Rise. Regarding the outlet water temperature 
for gas-fired instantaneous water heaters, the Controlled Energy 
Corporation (CEC) submitted a written statement to DOE and distributed 
the statement at the February 1997 workshop. CEC stated that the outlet 
water temperature for an instantaneous water heater should be at 110-
115 deg.F because there is no practical domestic use for water at 
135 deg.F. (CEC, February 1997 Transcript at Appendix H at 4 and No. 63 
at 3.) Additionally, CEC claimed the 135 deg.F temperature specified 
for storage-type water heaters is simply to increase the heat content 
of the stored water and therefore is not relevant for instantaneous 
water heaters. (CEC, February 1997 Transcript at Appendix H at 4.)
    Group Thermo suggested that a 50 deg.F temperature rise is too low 
for some cold regions of the country, and Bock suggested it is too low 
for certain well water sources. EEI supported a temperature rise of 
50 deg.F because there are many places like Miami and Texas with high 
ground water temperatures for

[[Page 25999]]

most, if not all, of the year. EPRI supported a 50 deg.F temperature 
rise because that is representative of typical human usage and a rise 
of 77 deg.F because that is typical of machine usage. A.O. Smith 
favored a single rating at a 77 deg.F temperature rise because it is 
simpler and allows comparisons with storage-type water heaters. (Group 
Thermo, February 1997 Transcript at 133 and 138; Bock, February 1997 
Transcript at 132; EEI, February 1997 Transcript at 136; A.O. Smith, 
February 1997 Transcript at 141; and EPRI, No. 56 at 11.)
    The Department will continue to specify the test conditions for 
water heater temperatures at 58 deg.F inlet (Title 10 CFR, Part 430, 
Subpart B, Appendix E, Section 2.3) with a 77 deg.F rise to address (1) 
machine-use applications that require a 135 deg.F water temperature for 
efficient operation, and (2) the performance of a water heater in 
regions of the country that may have a significantly lower supply 
(inlet) temperature. Additionally, a single value of 77 deg.F rise will 
reduce the test burden on manufacturers.
    d. Draw Schedule. DOE did not propose any changes in the draw 
schedule for instantaneous water heaters. There were several comments 
addressing this issue. During the 1997 workshop, EPRI commented that 
for large, whole-house, fossil-fueled instantaneous water heaters, the 
losses due to warm-up and cool-down after each water draw become 
significant because of the thermal mass of the water and the heat 
exchanger. Also, EPRI stated the number of draws (six) in the existing 
test procedure for energy factor (EF) tests is not high enough to 
account for the daily total cyclical loss that occurs in practice. EPRI 
claimed that in the field there are 20-50 draws per day. EPRI suggested 
that tests be conducted on smaller tank types and whole-house 
instantaneous water heaters to compare the difference in losses caused 
by a larger number of draws throughout the day. (EPRI, February 1997 
Transcript at 166, 173, and 178.)
    In its written statement, CEC also requested that the draw schedule 
in the 24-hour simulated use test for modulating gas-fired 
instantaneous water heaters be changed from an equal number of draws at 
the maximum and minimum firing rates (three at each) to 75% of the 
draws at the maximum firing rate and 25% at the minimum firing rate. 
CEC stated that this would reflect the fact that most of the daily hot 
water consumption is at the maximum firing rate, which, CEC stated, is 
when the efficiency of its heater is highest. CEC stated that the 
minimum firing rate is provided for the convenience of consumers for 
hand washing, etc. (CEC, February 1997 Transcript at Appendix H at 3 
and No. 63 at 2.)
    DOE recognizes that the number of draws will affect the energy 
factor and the annual energy consumption of instantaneous water 
heaters. The reason is that the warm-up and cool-down of the heat 
exchanger between hot water draws will reduce the measured average 
outlet temperature from the specified nominal 135 deg.F resulting in a 
lower energy factor and a higher energy consumption when the outlet 
temperature is adjusted back to the nominal temperature in the 
calculation procedure. The decrease in outlet temperature is 
proportional to the number of draws under a constant total daily draw 
volume. However, DOE has no data on the amount of daily hot water usage 
at the minimum or maximum firing rate for modulating gas-fired 
instantaneous water heaters. Hence, there is no basis for DOE to change 
the number of draws for instantaneous water heaters at either a fixed 
firing rate or for modulating instantaneous water heaters at the 
minimum or maximum firing rate in the 24-hour simulated use test. 
Additionally, DOE needs data to substantiate any change to the number 
of draws during the 24-hour simulated use test for instantaneous water 
heaters because changing the number of draws is likely to reduce the 
energy factor for existing units thereby requiring a modification to 
the energy conservation standard for those products.
    e. Energy Factor Measurement. DOE proposed a 24-hour simulated use 
test for instantaneous water heaters that is exactly the same as the 
24-hour simulated use test for storage-type water heaters. The 24-hour 
simulated use test would determine the amount of fuel or electricity 
used during a 24-hour period to heat 64.3 gallons of water to 135 deg.F 
with the water being drawn in six equal draws at one-hour intervals. 
Also, if the instantaneous water heater allows variable input rates, 
the fuel or electricity consumed to heat 64.3 gallons of water to 
135 deg.F during a 24-hour period would be determined with three draws 
at the maximum flow rate and three draws at the minimum flow rate. In 
the current test procedure, the recovery efficiency is calculated from 
the output energy of the first draw (determined from water mass, 
temperature, and specific heat) divided by the measured input energy 
used during the first draw of the 24-hour simulated use test for units 
with a single firing rate. For modulated units, the recovery efficiency 
is the average of the two recovery efficiencies calculated on the basis 
of data from the first draw (at the maximum input rate) and the fourth 
draw (at the minimum input rate) of the 24-hour simulated use test.
    In its comments to the 1995 proposed rulemaking, Paloma Industries, 
Inc., suggested that for gas-fired instantaneous water heaters, two EF 
values should be determined in the test procedure. These values would 
reflect test conditions with (1) the pilot light being continuously on, 
and (2) the pilot light being off except when hot water is needed. The 
pilot-light-on condition is the case in which the pilot light is always 
on regardless of whether there is a demand for hot water. The second 
test condition is for the case in which a consumer turns the pilot 
light off when hot water is not needed. Paloma claims that with its 
Piezo-Elecric Ignition and Subsidiary Pilot Burner Assembly, the 
consumer can manually light the pilot easily (in about 10 seconds time) 
when hot water is needed. CEC concurred with Paloma. (Paloma 
Industries, No. 7 at 3; CEC, February 1997 Transcript at Appendix H at 
4 and No. 63 at 2.) Furthermore, CEC stated that differentiating water 
heaters with pilot lights from those without is even more important 
because CEC will introduce a unit in 1998 with electronic ignition. 
(CEC, No. 63 at 2.)
    With respect to the issue of the pilot light status between hot 
water draws, GAMA recognized that turning off the pilot will reduce 
energy consumption and increase the energy factor. GAMA also stated 
that turning off the pilot light may not be practical for a whole-house 
application. Bock expressed the same opinion. Oregon suggested that it 
is possible to have two energy factors, one based on the pilot light on 
between draws and one based on it being off. Oregon also recommended 
that a test procedure for instantaneous water heaters should account 
for warm-up, cool-down and pilot light losses. (GAMA, February 1997 
Transcript at 170 and 176; Bock, February 1997 Transcript at 171; 
Oregon, No. 51 at 3.)
    DOE believes the suggestion to compute two energy factors is valid 
only if the consumer can conveniently turn the pilot light off and on 
automatically at the point of use (e.g., at the faucet or showerhead) 
and if no other faucet or appliance requiring hot water is connected to 
the same water heater. Neither Paolma nor CEC indicated that such an 
approach was possible with their equipment although CEC has stated that 
it will introduce a model with electronic ignition in 1998. DOE 
believes that manual shut-off for pilot lights on instantaneous water 
heaters

[[Page 26000]]

would not be practical for widespread use and energy savings. 
Therefore, DOE will continue to calculate one energy factor.
2. Storage-type Water Heaters With Rated Storage Capacities Less Than 
20 Gallons
    In the 1995 proposed rulemaking, DOE proposed to cover storage-type 
water heaters with rated storage capacitites less than 20 gallons (76 
liters). This proposal was in response to a July 17, 1991, letter from 
GAMA that stated that storage-type water heaters less than 20 gallons 
(76 liters) are not covered by the existing test procedure.
    To cover these water heaters, DOE proposed to adopt the draw rate 
and the schedules in ANSI/ASHRAE Standard 118.2-1993, ``Method of 
Testing for Rating Residential Water Heaters,'' to be used in the 
first-hour rating test and the 24-hour simulated use test. The draw 
schedules are as follows: (1) For units with rated storage less than 10 
gallons (38 liters), a total volume of 9 gallons (34 liters) shall be 
withdrawn, and (2) for units with rated storage greater than or equal 
to 10 gallons (38 liters) but less than 20 gallons (76 liters), a total 
volume of 24 gallons (91 liters) shall be withdrawn. The draw rate for 
both draw schedules shall be 1.0 gallon  0.25 gallons per 
minute (3.8 liters 0.95 liters per minute). DOE also requested 
comments and data on its proposal to extend test procedure coverage to 
storage-type water heaters of less than 20 gallons (76 liters).
    Several commenters objected to one or more of these proposals. 
These commenters variously cited the following reasons: (1) The 
existing minimum efficiency standards are based on field applications 
and usage requirements for larger volume water heaters and are 
inappropriate for smaller-volume water heaters, for example, fitting 
and connection losses would be unfairly treated for smaller-volume 
water heaters because those losses would represent a larger percentage 
of total losses; (2) it is difficult to install thermocouples and to 
control flow rates in smaller-volume water heaters; (3) smaller-volume 
water heaters cannot meet the efficiency requirement because they 
typically are installed in confined areas, which limits the amount of 
insulation used to reduce surface losses; and (4) a flow rate of 1 gpm 
during water draws is too large for smaller water heaters' it would 
quickly deplete the quantity of hot water in tanks of 2.5 gallons or 
less. (GAMA, No. 1 at 3, No. 35 at 3, and July 1995 Transcript at 12; 
EPRI, No. 17 at 2; EEI, No. 2 at 6, No. 27 at 5, and July 1995 
Transcript at 28; Oregon, No. 51 at 3 and February 1997 Transcript at 
164 and 195; TVA, No. 14 at 1; The Southern Company Services, Inc., No. 
24 at 2; American Electric Power, No. 38 at 1; Potomac Electric Power, 
No. 26 at 3; CSW, No. 4 at 2; Centerion Energy, No. 22 at 1; Nevada 
Electric Power, No. 45 at 2; National Rural Electric Cooperative 
Association, No. 18 at 2; Decatur County REMC, No. 19 at 1; and Dayton 
Power and Light, No. 20 at 1.)
    GAMA suggested that separate piping arrangement figures be used for 
floor-mounted models of less than 20 gallons storage capacity. GAMA 
provided the schematic drawings for its suggested changes. (GAMA, No. 1 
at 6 and July 1995 Transcript 17.)
    Vaughn Manufacturing Corporation claimed: (1) The number of units 
is a small percentage of the total; (2) this is a utilitarian product 
which is used to fit special circumstances when other alternatives are 
not available; and (3) the publication of energy factors will not cause 
the purchaser to choose a more efficient model to an extent that will 
make a significant difference in national energy conservation. (Vaughn, 
No. 31 at 2.)
    However, AGA believed that the large number of such heaters sold 
justifies some measurement that could be used for a minimum standard. 
(AGA, February 1997 Transcript at 184-185.) GAMA proposed running only 
a stand-by loss test for the measurement, and EPRI proposed to base 
this measurement on the maximum stand-by loss without considering daily 
water consumption. GAMA argued that any standard would have to be 
connected to some level of daily consumption. The FTC pointed out that 
if the test procedure covers these products, they would have to be 
labeled, and the label has to contain a value for energy consumption. 
In its written comments, GAMA stated that the applicable maximum hourly 
stand-by loss requirement in ASHRAE 90A-1980 was 43W. GAMA asserted 
that because the ASHRAE loss was based on an 80 deg.F temperature 
difference, the DOE maximum loss rate should be 36.3W, based on the 
67.5 deg.F temperature difference for the DOE test. GAMA concluded that 
the DOE proposal for the 24-hour simulated use test should be scrapped 
and that only an hourly stand-by loss should be measured by the test 
procedure. (GAMA, No. 35 at 4 and February 1997 Transcript at 165 and 
185-186; EPRI, February 1997 Transcript at 183-184; and FTC, February 
1997 Transcript at 186.) This proposal was not supported by Virginia 
Power, who claimed that losses for fittings were greater for small 
tanks and that specialized uses for these tanks may limit the kinds of 
modifications leading to improved efficiency. Oregon supported the 
stand-by loss proposal and added that heaters with capacity equal to or 
less than 2 gallons (7.6 liters) be exempt from coverage and that all 
water heaters less than 20 gallons (76 liters) be exempt from the 
Energy Guide labeling requirement. EPRI expressed general support for 
GAMA's proposal, but suggested that a combination of stand-by loss and 
recovery efficiency rather than a single energy efficiency term be used 
to determine the energy standard for small water heaters. (Virginia 
Power, No. 42 at 3; Oregon, No. 51 at 3 and February 1997 Transcript at 
164 and 195; EPRI, No. 56 at 5 and February 1997 Transcript at 164, 
183, and 188 and at Appendix J at 2.)
    Although the Department believes the stand-by loss measurement for 
water heaters less than 20 gallons (76 liters) proposed by GAMA and 
EPRI may be feasible, DOE will reserve consideration of this proposal 
for a future revision of the test procedure. The reasons for this 
decision are: (1) Absence of data to determine the appropriate daily 
hot water consumption, and (2) DOE's need to develop and evaluate the 
stand-by loss procedure. Therefore, DOE is withdrawing its proposal in 
today's Final Rule.
3. Definitions
    In the 1995 proposed rule making, DOE solicited comments on the 
addition to the test procedure of definitions of a heat pump water 
heater storage tank and a solar water heater. DOE also proposed to 
revise the definition of a heat pump water heater to specify two types, 
an integral heat pump water heater and an add-on heat pump water 
heater.
    The following discussion ensued:
    (i) Solar Water Heater. GAMA stated that it did not understand the 
purpose or intent of the expanded definitions or the need to define 
``solar water heaters'' for the test procedure. GAMA suggested that the 
requirement that a solar water heater obtain 50% of its annual heating 
energy from the sun is not a definitive criterion because a solar water 
heater with less than 50% of its input energy from the sun is still a 
solar water heater. (GAMA, July 1995 Transcript at 15 and No. 1 at 5.)
    (ii) Heat Pump Water Heater Storage Tank. During the February 1997 
workshop, GAMA proposed that a 50-gallon tank standardized with respect 
to the energy factor is adequate and should be used to test any add-on 
heat pump water heater sold without a tank by its manufacturer. (The 
existing DOE test

[[Page 26001]]

procedure specifies a 47-gallon tank meeting the minimum standard 
energy factor or not greater than .02 EF above the minimum.) GAMA 
objected to the Department's proposal for a special heat pump water 
heater storage tank.
    EPRI objected to the inclusion of a special heat pump water heater 
storage tank, and proposed that an add-on heat pump water heater be 
tested with a standard 50-gallon tank as required under the existing 
DOE test procedure. EPRI further stated that there are no storage tanks 
labeled and designed for use exclusively with heat pump water heaters. 
All other commenters, such as the Oregon Energy Office and Virginia 
Power, agreed with GAMA's and EPRI's proposals for a standard 50-gallon 
tank. The Oregon Energy Office called for a revision of the original 
definition. (GAMA, February 1997 Transcript at 229; EPRI, No. 17 at 5 
and February 1997 Transcript at 227; Oregon, No. 51 at 6; Virginia 
Power, No. 50 at 4.)
    (iii) Add-on Heat Pump Water Heaters. EEI expressed concerns about 
the definition of add-on heat pump water heaters. EEI and EPRI claimed 
the definition is inappropriate and should not be adopted. They stated 
that add-on heat pump water heaters are designed to work with any 
electric water heater tank and that some are designed to work with any 
tank. EPRI claimed the new definition limits the availability of tanks 
for use with add-on heat pump water heaters. EPRI believes that this 
new definition would increase the cost. Further, EEI found that this 
definition is ill-advised, because new tanks of essentially identical 
construction must meet two definitions, thus creating confusion and 
potentially increasing the cost of heat pump water heaters. (EEI, No. 2 
at 7, and No. 27 at 7; EPRI, No. 17 at 5.)
    Virginia Power proposed deleting ``heat pump'' from the last line 
of the definition. (Virginia Power, No. 50 at 4.)
    Vaughn Manufacturing Corp. commented that the addition of more than 
one category of heat pump water heaters, or even solar water heaters, 
will add to the confusion because it may lead consumers to compare test 
results of dissimilar types of water heaters. (Vaughn, No. 31 at 4.)
    (iv) Integral Heat Pump Water Heaters. GAMA suggested that, instead 
of the 1995 DOE proposed definitions of ``integral heat pump water 
heaters'' and ``add-on heat pump water heaters,'' the respective 
definitions should be ``heat pump water heaters with tanks'' and ``heat 
pump water heaters without tanks''.
    Also, GAMA objected to the term ``integral heat pump water 
heaters'' because it implies that the heat pump is structurally 
integrated with a tank, whereas in reality, the heat pump and the tank 
can be physically separated, but are usually sold by the manufacturer 
as a packaged unit. (GAMA, February 1997 Transcript at 230.)
    Virginia Power proposed deleting the definition of ``integral heat 
pump water heater.'' (Virginia Power, No. 50 at 4.)
    (v) Proposed Revisions. DOE responded to these comments in the 
October 1997 reopening notice. In this notice, DOE proposed the 
following revisions:

     Withdraw the definition of solar water heaters.
     Withdraw the proposal for heat pump water heater storage 
tanks for testing with an add-on heat pump water heater.
     Delete the definition of integral heat pump water heaters.
     Replace the definition of ``integral heat pump water 
heaters'' with the definition, ``Heat pump water heater with storage 
tank means an air-to-water heat pump sold by the manufacturer with an 
insulated storage tank as a packaged unit. The tank may be integral 
with or separated from the heat pump.''
     Replace the definition of ``add-on heat pump water 
heater'' with the definition, ``Heat pump water heater without storage 
tank (also called add-on heat pump water heater) means an air-to-water 
heat pump designed for use with a storage-type water heater or with a 
storage tank that is not specified or supplied by the manufacturer.''
    EEI, Virginia Power, and GAMA supported DOE's proposed definitional 
changes in the October 1997 notice of reopening. (EEI, No. 65 at 1; 
Virginia Power, No. 66 at 4; and GAMA, No. 67 at 1.) No commenter took 
issue with the proposed definitional changes.
    Therefore, DOE is adopting in this Final Rule the proposed revision 
as stated above.
4. Heat Pump Water Heaters
    a. Back-up Electric Resistance Heating. In the Proposed Rule, the 
Department requested comments on the adequacy of the existing test 
procedure regarding back-up electric heating elements for heat pump 
water heaters because the current test setup and parameters may not 
represent operating conditions requiring the resistance element(s) to 
be activated. The existing procedure does not account for energy used 
by these elements because most heat pump water heaters are capable of 
meeting the test draw requirements of the 24-hour simulated use test 
for the energy factor and, therefore, the back-up electric resistance 
heating element(s) is not activated.
    GAMA stated that the current draw schedule is such that the back-up 
electric resistance element(s) does not turn on during testing. 
Although GAMA concluded from tests conducted at Intertek Testing 
Service (ITS) that changing the current draw schedule by increasing the 
volume of water withdrawn will not activate the elements, it still 
argued that in residential applications, a significant percentage of 
the energy for water heating (15-20%) comes from the back-up resistance 
element(s). GAMA asserted that this energy should be included in 
determining the annual energy consumption of the heat pump water 
heater. This view is shared by the Southern Company Services (SCS). 
(GAMA, No. 1 at 5, No. 35 at 5, July 1995 Transcript at 16, and 
February 1997 Transcript at 241; and SCS, No. 24 at 2.) Vaughn 
Manufacturing Corporation claimed that the one-hour recovery between 
the six small draws prejudices the test procedure in favor of heat pump 
water heaters. Furthermore, Vaughn claimed, this test profile is not 
based on a representative average use cycle. (Vaughn, No. 31 at 3.) 
Georgia Power recommended that the draw schedule continue to stipulate 
10.7 gallons per draw for each hour. (Georgia Power, No. 54 at 2.)
    GAMA recommended adding some electrical energy to the annual energy 
consumption calculation but GAMA did not recommend a specific amount of 
energy. GAMA claimed that this electrical energy was necessary because 
no resistance heating was measured during tests of heat pump water 
heaters using the DOE test procedure and GAMA claims that it is well 
accepted that heat pump water heaters use backup resistance heating 
during periods of heavy draws. (GAMA, No. 57 at 2 and February 1997 
Transcript at 240-260.) The recommendation was supported by AGA and the 
Oregon Energy Office. (AGA, February 1997 Transcript at 254 and 263; 
Oregon, February 1997 Transcript at 248, 250, and 255; and Oregon, No. 
51 at 5.)
    However, EPRI claimed that its data shows that less than 10 percent 
of the energy consumption for water heating with heat pumps actually 
comes from the back-up resistance elements for customers who use about 
64 gallons of hot water per day. EPRI argued that it would be improper 
to apply a correction factor to compensate for resistance elements that 
do not activate during average test conditions. Moreover, EPRI added 
that if a correction factor is applied to heat pump water heaters,

[[Page 26002]]

then correction factors due to regional conditions would need to be 
applied to all types of water heaters. Based on these reasons, EPRI is 
opposed to the recommendation by GAMA. (EPRI, No. 56 at 2, February 
Transcript at 239, 248, 257 and 264 and at Appendix J at 2.) Virginia 
Power agreed with EPRI's comments. (Virginia Power, No. 50 at 4, and 
February 1997 Transcript at 249 and 258.)
    Other opponents to GAMA's recommendation included Abrams and 
Associates, who commented that the purpose of the test procedures is to 
rate water heaters for comparison purposes rather than to reflect 
actual household applications. Lawrence Berkeley National Laboratory 
(LBNL) stated that heat pump water heaters do not need a separate test 
procedure to account for backup resistance heating because of their 
insignificant market share and greater efficiency. EEI commented that 
to activate the heating elements would require a draw in excess of 50 
gallons, which is not realistic. AIL Research stated that no correction 
factor should be used until data becomes available. (Abrams, February 
1997 Transcript at 260; LBNL, February 1997 Transcript at 252; EEI, 
February 1997 Transcript at 255; and AIL, February 1997 Transcript at 
261-264.)
    The Department believes that the 24-hour simulated use test for the 
energy factor must be based on average test conditions that also apply 
to other water heaters of comparable size and use so that all storage-
type water heaters are tested and rated on a consistent and uniform 
basis. Furthermore, DOE notes that based on test data submitted by 
GAMA, the back-up heating elements for heat pump water heaters will not 
activate when the volume of hot water drawn is changed from 10.7 
gallons to a more severe 21.4 gallons per draw during two of the six 
draws of the 24-hour simulated use test. The Department believes that 
any single draw in the draw schedule greater than the 21.4 gallons per 
draw (as tested) would not be considered as an average use pattern. 
Because the test procedure is for comparison purposes and is not 
intended to take into account all potential field use patterns (such as 
the draw-down of the storage tank), DOE considers that a revision to 
the current draw schedule of 10.7 gallons per draw for the six draws in 
the 24-hour simulated use test (for example, stipulating 21.4 gallons 
per draw for two of the six draws) is not necessary because it will not 
change the result. Furthermore, there is no agreement on an average 
percent of the annual energy consumption that comes from the resistance 
heating elements. Therefore, the Department concludes that applying a 
correction to the energy factor and/or annual energy consumption of the 
heat pump water heater to account for the energy used by the resistance 
elements that do not activate during testing is unwarranted and will 
not be included in today's Final Rule.
    b. Installation Requirements. The installation requirements in 
Section 4.1 of Appendix E of the current test procedure state that a 
heat pump water heater without a manufacturer-supplied storage tank 
shall be connected to the storage tank in accordance with the 
manufacturer's instructions. The requirements further state, ``If 
installation materials are not provided by the heat pump manufacturer, 
use uninsulated 8 foot (2.44 m) long connecting hoses, having an inside 
diameter of 5/8 inch (1.6 cm).'' The intent of this requirement is to 
specify a uniform test setup for those units that do not include 
manufacturer's instructions. DOE asked for comments on this issue.
    EPRI commented that the term ``installation materials'' in this 
context is unclear. EPRI suggested changing ``installation materials'' 
to a more descriptive term because most manufacturers of add-on heat 
pump water heaters, or any other type of water heater, do not provide 
the plumbing hardware and should not be penalized for not doing so. 
(EPRI, No. 17 attached report at 6.) American Electric Power claimed 
that the installation requriements were vague. (American Electric, No. 
38 at 1.) Oregon suggested that in cases in which manufacturers do not 
include instructions, the test procedure should be performed using 
insulated hoses of sufficient length and size to properly mount the 
heat pump unit relative to the storage tank. (Oregon, No. 51 at 6.)
    To make the wording clear, DOE is revising the text in section 4.1 
of Appendix E from ``installation materials'' to ``installation 
instructions'' as suggested by EPRI. DOE disagrees with Oregon's 
comment because in most residences, the hot water pipes usually are not 
insulated. DOE believes that the 8-foot hose is adequate to make the 
heat-pump-to-water-heater connection and ensure that the heat loss from 
the uninsulated hose is equal for all add-on heat pump water heaters 
that do not have manufacturers' installation instructions.
    c. Heat from the Ambient Air. The current and proposed test 
procedures use the same test conditions and test procedures for oil-
fired, electric and heat pump water heaters. Vaughn claimed that 
because the DOE test procedure does not account for heat removed from 
the ambient air, the procedure favors heat pump water heaters. (Vaughn, 
No. 31 at 3.)
    The Department has considered this topic and has concluded that the 
interactions between heat pump water heaters and the building 
environment are extremely complex and difficult to measure. 
Furthermore, in some cases, heat pump water heaters may be installed 
outside the building, in which case the heat removed from the ambient 
air is free and does not need to be counted. For these reasons, DOE 
will address building and heat pump interactions in a future 
rulemaking.
5. First-Hour Rating for Storage-type Water Heaters
    In the 1995 proposed rulemaking, DOE proposed a revised test 
procedure for the first-hour rating for storage-type water heaters. The 
proposed revision specifies the start of a first draw at the beginning 
of the one-hour period, when the average tank temperature is at the 
specified limit of 135 deg.F  5 deg.F (57.2 deg.C 
 2.8 deg.C) and all the thermostats are satisfied. The 
first draw is terminated when the outlet water temperature decreases by 
25 deg.F (13.9 deg.C) below the maximum outlet temperature recorded 
during the draw. Successive draws are initiated when the uppermost 
thermostat is satisfied following a tank recovery, and ended when the 
outlet water temperature decreases by 25 deg.F (13.9 deg.C) below the 
maximum outlet temperature recorded during each particular draw.
    At the end of the one-hour period, a final draw is initiated if no 
draw is in progress. This draw is terminated when the outlet water 
temperature decreases to the value used to terminate the draw that was 
completed before this final draw. If a draw is in progress at the end 
of the one-hour period, this draw is continued until the outlet water 
temperature decreases by 25 deg.F (13.9 deg.C) below the maximum outlet 
temperature recorded during this draw. A temperature correction factor 
is applied to the last draw. The correction factor is a quotient in 
which the numerator is the average delivered water temperature of the 
last draw minus the minimum water temperature of the next-to-last draw 
and the denominator is the average delivered water temperature of the 
next-to-last draw minus the minimum water temperature of the next-to-
last draw. The correction factor corrects for any significant reduction 
in energy content of the draw due to a lower average outlet water 
temperature over the draw

[[Page 26003]]

than those obtained during the earlier draws.
    Thermally compensating dip tubes and integral mixing valves result 
in higher first-hour ratings. DOE did not propose to apply a correction 
factor to water heaters employing these features because the Department 
was unaware of the existence of these features on currently 
manufactured water heaters. However, EPRI, EEI, and Nevada Power 
Company stated that because at least one U.S. manufacturer has 
purchased the right to manufacture and sell the equivalent of an 
``internal mixing'' product, DOE should develop a procedure that 
accounts for differences in hot water delivery temperatures. (EEI, No. 
27 at 5; EPRI, No. 17 at 12; and Nevada Power Company, No. 45 at 3.) 
Southern Company Services (SCS) argued that specifications for mixing 
valves (similar to internal mixing) are not relevant to efficiency and 
the use of mixing valves should not be restricted. Furthermore, SCS 
supported the test procedure proposed by Dr. Carl Hiller of EPRI, which 
it claimed would not be affected by mixing valves. (SCS, No. 24 at 2.)
    EEI and EPRI commented that DOE's proposed first-hour rating 
procedure, while an improvement over the current (1991 Final Rule) and 
previous (1978) DOE procedures, is still flawed and should not be 
implemented. Both EEI and EPRI based their comments on the analysis of 
the DOE proposed procedure by Dr. Carl Hiller of EPRI. (EEI, No. 2 at 
2, No. 27 at 2, and July 1995 Transcript at 22; and EPRI, No. 17 
attached report at 2.)
    Dr. Hiller commented that the DOE proposed procedure is based on 
unrealistic water consumption behavioral patterns, and bears little 
relevance to the sizing of hot water systems. Dr. Hiller stated that 
the procedure gives misleadingly high ratings to units having a high 
heat input rate, thus penalizing electric systems and systems with 
larger tanks. Dr. Hiller suggested that the entire proposed procedure 
should be abandoned and replaced with an alternative developed by EPRI. 
(EPRI, No. 17 at 9 and 13.)
    Specifically, Dr. Hiller claimed that the DOE proposed first-hour 
rating procedure for storage-type water heaters is characterized by the 
following: (1) It penalizes large tanks because the draw rate of 3 gpm 
causes the draws to take longer for larger tanks, thus limiting useful 
reheat time; (2) the temperature correction factor applied to the last 
draw is cumbersome; (3) the draw at the end of the one-hour test 
results in a variable test time; (4) depending on the thermostat 
setting and behavior, two similar tanks may show dramatic differences 
in their first-hour ratings; (5) the one-hour time period in the 
procedure is arbitrary and relatively irrelevant to water heating 
system sizing; and (6) the procedure fails to account for the energy 
content of water delivered at different temperatures during the draws. 
(EPRI, No. 17 at 9-13.)
    Dr. Hiller proposed three EPRI alternatives to DOE's first-hour 
rating procedure. The first alternative calculates first-hour rating as 
the sum of (1) the volume of water from an initial draw (multiplied by 
a factor to correct to a uniform delivery temperature of 110 deg.F 
(43.3 deg.C) and (2) the maximum useful reheat volume (water is heated 
to 110 deg.F [43.3 deg.C]) at the rated energy input between the end of 
the first recovery (after the first draw) and the end of a specified 
reheat time period. This EPRI proposal uses a calculation to determine 
the maximum useful reheat volume during the specific reheat period; 
EPRI notes that the maximum useful reheat volume could also be 
determined with actual draws. In this proposal, EPRI advocates a reheat 
period of 35-45 minutes instead of one hour. (EPRI, No. 17 at 13.)
    The second EPRI alternative, proposed by Dr. Hiller at the February 
1997 workshop, bases tank sizing on a graph of the way hot water is 
actually used over a specific time period together with graphical 
representations of hot water delivery capability (a stepwise function 
versus time due to reheat delay) for various water heaters. The water 
heater size is found by overlaying the two graphs of hot water delivery 
capability and hot water consumption requirement. EPRI provided 
examples of data for several tank sizes for hot water delivered not 
exceeding once per day, once per week and once per month derived from a 
2\1/2\ year EPRI field study at 14 metered sites with electric storage-
type water heaters. (EPRI, No. 56 at 6, and February 1997 Transcript at 
Appendix J at 4-10.)
    In its comments after the February 1997 workshop, EPRI proposed a 
third alternative first-hour rating procedure, which modified its first 
proposal. In this procedure, hot water is drawn initially and during 
four reheat cycles. Data from the five corresponding draws (stepwise in 
form as in the second alternative) are used to establish a graphical 
representation of hot water availability versus time, including the 
reheat time delay between the first draw after recovery (on the basis 
of the cut-out of the uppermost thermostat) and the subsequent draw. 
From these measurements, the actual first draw volume available and the 
actual average reheat rate of the system are determined. After the 
first reheat is completed, a linear calculation is performed to 
estimate the number of additional gallons that can be produced based on 
the average reheat rate. Then the ``minimum'' maximum water 
availability curve is calculated. The hot water delivery rating from 
the graph is determined based on the minimum hot water availability 
curve together with a ``critical design time interval'' of 35 minutes. 
EPRI claimed that this procedure accounts for the first draw volume and 
the reheat rate, as well as the reheat time delay between the hot water 
run-out after the first draw and the completion of the recovery (on the 
basis of the cut-out of the uppermost thermostat). EPRI claimed that 
this procedure is better than the DOE proposed procedure because the 
reheat delay time is accounted for. The third alternative differs from 
the first alternative primarily because the third alternative involves 
four cycles of reheating, and the water temperature at the top of the 
tank after recovery is at 135 deg.F (57.2 deg.C) instead of 110 deg.F 
(43.3 deg.C). (EPRI, No. 56 attached report at 11-12.)
    This proposal includes an optional method that permits 
manufacturers to list the first draw as the first draw rating because 
the 35-minute hot water delivery rating is typically at or near the 
first draw capability of the tank. This avoids the need to perform the 
four reheats and five draws. (EPRI, No. 56 attached report at 13.)
    Virginia Power and American Electric Power (AEP) also stated their 
opposition to the DOE first-hour rating and their support of a maximum 
first draw rating. Virginia Power claimed that the maximum first draw 
rating more accurately represents typical consumer action. (Virginia 
Power, No. 50 at 2; AEP, No. 53 at 1.)
    Rheem Manufacturing claimed the first-hour rating is seldom used by 
consumers in purchasing water heaters. (Rheem, February 1997 Transcript 
at 154-155.)
    Georgia Power claimed that the first-hour rating is biased toward 
gas-fired water heaters. Georgia Power proposed an alternative method 
which involves checking the temperature in the top of the tank 
periodically after the first draw is complete. When the temperature is 
above the minimum setpoint temperature, a second draw should begin. It 
claimed that this procedure reflects the way a consumer would use hot 
water after a run-out. (Georgia Power, No. 54 at 1.)
    GAMA stated that it does not support EPRI's alternative first-hour 
rating

[[Page 26004]]

procedures. GAMA claimed that the current and proposed DOE test 
procedure, in which water is drawn from a tank full of heated water and 
then subsequent draws are made each time the tank returns to the 
setpoint temperature within an hour, is an appropriate way to evaluate 
a water heater's capability to provide heated water. GAMA stated that 
the DOE procedure may require some modifications and corrections in the 
calculations, but GAMA did not believe it is necessary to rewrite the 
entire first-hour rating procedure (as suggested by EPRI). (GAMA, No. 1 
at 2, and No. 35 at 2, and July 1995 Transcript at 10.)
    GAMA claimed the 1990 procedure gives a first-hour rating volume 
that may be smaller than the first draw volume for larger tanks. GAMA 
presented the results of tests conducted by its water heater 
manufacturer members that compared representative models of gas-fired 
and electric water heaters. The test results were compiled from both 
the current test procedure and the 1995 DOE proposed first-hour rating 
test procedure. The data show that the proposed procedure does provide 
a first-hour rating that reflects a combination of the water heater's 
storage capacity and recovery rate. In a written submittal at the 
February 1997 workshop, GAMA presented additional test results 
conducted by Intertek Testing Service on water heaters tested in the 
GAMA efficiency certification program. The data showed that 53 gas-
fired water heaters (with storage capacities of 30-50 gallons) were 
tested, and the difference between the first-hour rating using the 
proposed procedure and the first-hour rating based on the current 
procedure varied from -0.2 gallons to 8.0 gallons with a standard 
deviation for each tank volume class tested of 3.7-6.0 gallons. The 
data also showed that 51 electric water heaters (with storage 
capacities of 30-82 gallons) were tested, and the differences in rating 
value were from 3.7 gallons to 5.5 gallons with a standard deviation 
for each tank volume class tested of 2.0-5.8 gallons. GAMA believed 
that the data is indicative of a general trend and that it does support 
the use of the proposed first-hour rating test procedure. (GAMA, No. 1 
at 2, No. 35 at 2, and February 1997 Transcript at 91-92 and at 
Appendix I at 1-2.)
    GAMA, in the same written submittal at the February 1997 workshop, 
claimed DOE should provide an alternative conservative calculation for 
the first-hour rating. GAMA's suggested calculations are based on 1995 
and 1996 data from GAMA's efficiency certification program. The 1996 
data show that the volume of the first draw compared to the rated 
volume is about 0.85 for gas-fired water heaters and 0.78-0.85 for 
electric water heaters. GAMA proposed three calculations for first-hour 
rating: (1) For gas-fired water heaters, the first-hour rating equals 
0.8 of the tank volume plus an energy-based correction factor; (2) for 
dual-element electric water heaters, the first-hour rating equals 0.75 
of the tank volume plus an energy-based correction factor; and (3) for 
a single element electric water heater, the first-hour rating equals 
0.75 of the volume. GAMA claimed these calculations give conservative 
results. (GAMA, February 1997 Transcript at Appendix I at 1-2.)
    GAMA, in a later submittal following the February 1997 workshop, 
stated that its proposed optional first-hour calculation for electric 
water heaters should be modified to provide a more accurate first-hour 
value for larger volume models. It stated that the original calculation 
leads to an assumption that no recovery will occur for 24 minutes with 
an 80-gallon tank. GAMA stated that because the lower heating element 
turns on in 2-5 minutes into the first-hour rating test in all electric 
water heaters, GAMA decided to modify the volume-related correction 
factor for dual-element electric water heaters to reflect this. (GAMA, 
No. 57 at 1.)
    Supporters of the DOE proposal for determining the first-hour 
rating include the AGA, which finds it useful in determining the proper 
size of a water heater, stating that proper sizing is important for 
energy conservation, customer satisfaction and safety. (AGA, No. 55 at 
1.) The Oregon Energy Office recommended DOE adopt its 1995 proposal 
and not adopt any part of the EPRI proposals because Oregon claimed 
EPRI put too much weight on the first draw volume, thus promoting 
larger tanks. (Oregon Energy Office, No. 51 at 2 and February 1997 
Transcript at 110-112.) In a statement submitted after the February 
1997 workshop, Battelle Columbus presented some experimental data and 
analysis of a 35,500 Btu/h, 50-gallon gas-fired water heater. Battelle 
presented data to show that the test water heater was able to satisfy 
the ``once a month'' draw schedules based on the EPRI field tests of 15 
actual households. Battelle claimed that the test water heater could 
meet 12 of the 15 household hot water loads with a delivery temperature 
above 110 deg.F. Battelle claimed the data showed that the DOE first-
hour rating procedure is a good predictor of water heater performance. 
(Battelle, No. 58 at 1.)
    George Kusterer of Bock Water Heaters stated that the information 
relating to EPRI's alternate first-hour rating method is inconclusive 
and recommended it not be accepted by DOE. Bock also claimed that a 
first-hour rating based only on the first draw will not work. (Bock, 
February 1997 Transcript at 146, 151 and 153.)
    In response to EPRI's comments on the effect of the draw rate, DOE 
does not agree that a 3 gpm draw rate will result in a shorter reheat 
time for larger tanks. This is due to the fact that, for most electric 
water heaters, the bottom element will turn on within 5 minutes into 
the first draw. Also, a larger draw rate and a longer reheat time may 
not increase the total amount of hot water drawn because the heat input 
rate and not the draw rate will determine whether a tank can recover to 
a minimum temperature of 110 deg.F. This recovery capability is the 
reason that the size of the storage tank is not the only criterion for 
first-hour rating.
    Tank size is critical for simultaneous water usage, but tank 
recovery rate, either by a greater input rate or by dual--heating 
element design, could prove critical during times of consecutive hot 
water usages. While it is true that a consumer will not wait for the 
tank water temperature to reach 135 deg.F or the thermostat to cut out 
before turning on the hot water faucet, the one-hour rating does 
provide a simple and easy to understand indication of the combined 
effects of tank size and recovery rate within a reasonable time frame 
where heavy use of hot water may occur (for example, during the morning 
hours). It is also a definitive procedure for manufacturers to use for 
labeling but it is not necessarily an appropriate criterion for tank 
sizing since that depends on consumer behavior and uses of hot water.
    The temperature correction factor is used to adjust the volume of 
the last draw to account for the possible lower heat content of the 
last draw than those earlier draws with fully heated water. DOE has 
created the temperature correction factor as a simple arithmetic 
temperature ratio using temperature data that has already been measured 
during the test. DOE realizes that the temperature of the last draw may 
be at a lower temperature than those of earlier draws.
    DOE does not believe that due to the imposition of the last draw at 
the one-hour mark, two similar tanks, one at 111 deg.F and the other at 
109 deg.F, will result in a large difference in the amount of total 
volume drawn. The temperature correction factor is specifically applied 
to prevent that from happening. For example, assuming that the whole 
tank of water at 111 deg.F is drawn, the

[[Page 26005]]

temperature ratio, (111-110)/(130-110) = 0.05, will add only 5% of the 
last draw volume to the total volume drawn at the one-hour mark. (For 
illustration purposes, the maximum outlet temperature is assumed to be 
135 deg.F and the average outlet water temperature during a regular--
not the imposed--draw is assumed to be 130 deg.F.) DOE believes this 
difference of 5% of the volume of the tank is acceptable for grouping 
models of storage-type water heaters.
    There were claims that the DOE test period of one hour is too long. 
The one-hour time period is related to a similar period of high water 
consumption in most residences. Although the EPRI data indicates a 
shorter time, DOE believes that more data is necessary to establish a 
national average pattern of use, and DOE does not believe that a 
reduction of 25 minutes in test time, as suggested by EPRI, is merited. 
There were no comments from manufacturers or GAMA that the shorter test 
time was desirable. Rather, Darrell Paul, EEI, Bock, and Group Thermo 
stated that people tend to adjust their hot water use pattern during 
high consumption periods to account for short periods without hot 
water. (Battelle Columbus, February 1997 Transcript at 47; EEI, 
February 1997 Transcript at 49; Bock, February 1997 Transcript at 52; 
Group Thermo, February 1997 Transcript at 53.)
    Regarding the comment that a final draw results in a variable 
testing time, certainly the imposition of a final draw extends the test 
period beyond one hour. However, the procedure requires the cessation 
of input energy at the one-hour mark. Therefore, DOE believes this is 
an equitable way to account for all the usable heat energy input to the 
water heater within the one-hour time frame.
    DOE does not believe that a correction factor for hot water tanks 
with induced interim mixing will improve the accuracy of the test 
procedure enough to warrant its inclusion. DOE does agree that a 
temperature correction factor should be applied to the water drawn 
during each of the draws if a thermally compensating dip tube or an 
internal mixing device is used. However, at the present time there is 
no water heater that employs a mixing valve or thermally compensating 
dip tube during its normal operation. One design that does employ a 
mixing device is a special application for utility demand-side 
management in which higher temperature hot water is heated and stored 
during periods of low electricity demand. However, such a tank can be 
tested under the proposed DOE test. Therefore, a correction factor for 
induced internal mixing is not needed at this time.
    The Department reviewed and evaluated two of the proposals 
presented by EPRI (the second and the third, the latter of which is 
EPRI's modification of its first alternative). DOE considers that the 
second proposal, as stated by EPRI, is still in the development stage. 
DOE believes that when completely developed, the method may be included 
and used, in graphical or tabulated forms, in a design manual for use 
by designers to size the hot water tank for the needs of a particular 
customer. However, to adopt the procedure for a single number rating 
purpose would require the development of, and agreement by all 
concerned parties to, an average national utilization curve to be used 
in conjunction with EPRI's hot water delivery capability graphs for 
various models of water heaters. The Department believes that prospect 
will not be feasible in the near future. Furthermore, the Department 
believes that EPRI's third proposal should not be adopted. The reasons 
are (1) the procedure puts more weight on the first draw, which would 
tend to encourage the use of larger tanks; (2) the hot water produced 
during the recovery period is not included, even though it is available 
at the end of recovery; (3) the proposed four reheat cycles may require 
a very long test time, especially for larger electric tanks; (4) for 
water heaters with a lower heat input rate, the subsequent draw rate, 
which provides continuous 135 deg.F (heated up from the 58 deg.F inlet 
condition) water and is calculated on the basis of the reheat rate, 
will be much lower; and (5) the procedure, and any modification to it, 
has not been tested.
    The Department has decided not to adopt the optional calculation 
procedure proposed by GAMA. The Department checked the optional 
calculation procedure against data published in the GAMA directory and 
found that the results for first hour rating varied among electric, 
gas-and oil-fired water heaters. Furthermore, the coefficients proposed 
by GAMA were based on the current test procedure for first hour rating. 
The Department believes that the optional calculation may have merit, 
but the coefficients need to be based on the first hour rating in this 
Final Rule. For these reasons, the Department has decided to adopt the 
1995 proposed procedure for first-hour rating in today's Final Rule.
6. Installation of Under-the-Counter and Counter-Top Water Heaters
    The installation requirements in section 4 of Appendix E of the 
proposed test procedure do not distinguish under-the-counter water 
heaters from counter-top water heaters. GAMA recommended these be 
addressed separately because they are intended for different 
installations. GAMA indicated that because the water connections for 
counter-top models are within the water heater jacket, they can be 
installed flush to the back wall, and that this is not true for under-
the-counter models. GAMA also recommended that separate piping 
arrangements be provided for floor-mounted water heaters with storage 
capacities less than 20 gallons. GAMA submitted four figures 
illustrating these configurations. (GAMA, July 1995 Transcript at 17 
and No. 1 at 6.) Intertek Testing Services confirmed that GAMA's 
suggested changes are consistent with the normal practice in testing 
these types of models. Intertek further furnished piping schematics for 
those under-the-counter models that have a side inlet port and a top 
center outlet port. (Intertek, No. 62 at 1.)
    The Department supports these proposals. The Department understands 
that if a counter-top model is installed with the back surface of the 
water heater jacket flush against the wall, the heat loss through the 
back surface will be different from an installation in which the back 
surface is exposed directly to the ambient air. DOE also understands 
that for under-the-counter models, the limitation of space under the 
counter necessitates a short piping connection, which should be 
reflected in the installation requirement. Therefore, the installation 
figures for piping connections for under-the-counter and counter-top 
water heaters as provided by GAMA and Intertek are included in today's 
Final Rule (as Figures 3, 4, 5, 6, 7A, and 7B in Appendix E). Sections 
4.1 and 4.3 of Appendix E are revised to indicate these new figures and 
the requirement for a simulated wall against the back side of a 
counter-top model.
7. Test Conditions
    a. Daily Hot Water Usage. The current test procedure prescribes 
water heater testing to determine the energy factor must be based on a 
daily hot water usage of 64.3 gallons per day (gpd). DOE did not 
propose to change the daily hot water usage in the 1995 proposed 
rulemaking.
    The American Gas Association (AGA) and Battelle Columbus argued 
that the current daily hot water usage is outdated and proposed it be 
lowered to 54 gpd to reflect a recent study. (AGA, No. 25 at 2; and 
Battelle, No. 46 at 1.) Virginia Power suggested lowering the daily hot 
water usage to 50 gpd or less. Virginia Power also stated that because

[[Page 26006]]

the daily usage value is used in energy estimation and design 
calculations, changing it to a current value will maximize the 
usefulness and applicability of the test results. EEI suggested 
lowering the daily hot water usage to 50-57 gpd. Georgia Power argued 
for a value close to 50 gpd. (Virginia Power, No. 50 at 3 and February 
1997 Transcript at 212 and 223; EEI, February 1997 Transcript at 201; 
and Georgia Power, No. 54 at 2.) EPRI stated that there is substantial 
evidence, based on its recent study of submetered electric utility load 
data from 28 different sources, that the daily hot water consumption 
should be less than 50 gallons. However, EPRI, as well as GAMA, the 
Oregon State Energy Office, A.O. Smith, and Effikal International 
(Effikal), indicated that lowering the gpd value would not alter the 
relative efficiency ranking (based on energy factor) of the water 
heaters, but would impose an additional cost burden on industry for 
retesting and relabeling. The five commenters, therefore, suggested 
that DOE maintain the current daily hot water usage of 64.3 gpd in the 
test procedure. GAMA also suggested that, if necessary, it is possible 
to use linear estimation of energy consumption based on a different 
daily usage. The Oregon Energy Office suggested that the variation of 
the daily usage value with individual consumers is quite large, and the 
current 64.3 gpd may not be too far from the average. (EPRI, No. 56 at 
13 and February 1997 Transcript at 221 and at Appendix J at 2; GAMA, 
February 1997 Transcript at 215; Oregon State Energy Office, February 
1997 Transcript at 219; A.O. Smith, February 1997 Transcript at 220; 
Effikal, February 1997 Transcript at 224; and Oregon, No. 51 at 4.)
    The Department believes that the current value of 64.3 gpd is 
useful in determining an energy factor for consumers to use to compare 
water heaters. The Department believes that revising the value so it 
can be used to estimate or predict energy consumption will require a 
more detailed evaluation of individual installation locations, 
thermostat settings, and use patterns. Based on the fact that a revised 
daily hot water usage has not been agreed upon, and that the industry 
would be financially burdened, the Department concludes that revising 
the daily hot water usage is unwarranted in today's Final Rule.
    b. Storage Tank Temperature. The existing test procedure uses a 
thermostat setting of 135 deg.F  5 deg.F (57.2 deg.C 
 2.8 deg.C). DOE did not propose to revise this setting in 
the 1995 proposed rulemaking. AGA suggested that the thermostat setting 
be lowered to 120 deg.F  5 deg.F (48.9 deg.C  
2.8 deg.C) to reflect the manufacturers' recommendation to consumers to 
lower the temperature settings on water heaters thus preventing 
potential scalding. (AGA, No. 25 at 4.)
    Both Virginia Power and Bock Water Heaters also supported lowering 
the current thermostat setting to 120 deg.F (48.9 deg.C). The reasons 
cited included: (1) The current setting of 135 deg.F (57.2 deg.C) does 
not reflect how consumers actually operate their water heaters; (2) 
most energy-related organizations advocate a setting of 120 deg. 
F (48.9 deg.C) when promoting energy efficiency and safety; 
(3) scalding by hot water at 135 deg.F (57.2 deg.C) is a major concern 
in some areas; and (4) certain local codes restrict the thermostat 
setting to be no higher than 120 deg.F (48.9 deg.C). EEI stated that 
for several years many customers have been told to set their 
thermostats at 120 deg.F (48.9 deg.C). (Virginia Power, No. 50 at 3 and 
February 1997 Transcript at 212 and 223; Bock Water Heaters, February 
1997 Transcript at 207 and 211; and EEI, February 1997 Transcript at 
201.)
    In contrast, six commenters, individually or in support of another 
commenter's position, opposed lowering the thermostat setting from 
135 deg.F  5 deg.F (57.2 deg.C  2.8 deg.C). 
(EPRI, No. 56 at 2 and February 1997 Transcript at 199, 208, and 218 
and at Appendix J at 1; GAMA, February 1997 Transcript at 215 and at 
Appendix I at 3; Oregon State Energy Office, No. 51 at 4 and February 
1997 Transcript at 201, 204, and 219; Group Thermo, February 1997 
Transcript at 206; A.O. Smith, February 1997 Transcript at 220; and 
Effikal International, February 1997 Transcript at 224.) Their various 
comments are: (1) A setting at 120 deg.F (48.9 deg.C) could pose a 
potential health risk (e.g., legionella) to consumers; (2) a setting at 
135 deg.F (57.2 deg.C) is necessary to meet consumers' expected hot 
water needs (as with machine-use for washing clothes); (3) a setting at 
135 deg.F (57.2 deg.C) reflects realistic household settings; and (4) 
changing the thermostat setting from 135 deg.F (57.2 deg.C) will not 
alter the comparative ranking of water heaters but would result in a 
substantial cost to industry in retesting and relabeling. EEI stated 
that it would not object if the current requirement in the test 
procedure is not revised. (EEI, February 1997 Transcript at 220.)
    Based on the comments in the record regarding actual field 
thermostat setting by consumers, potential health concerns and the 
potential burden on industry, the Department concludes that revision of 
the thermostat setting from 135 deg.F  5 deg.F (57.2 deg.C 
 2.8 deg.C) to 120 deg.F  5 deg.F (48.9 deg.C 
 2.8 deg.C) is unwarranted in today's Final Rule.
    c. Ambient Air Temperature. The current DOE test procedure 
specifies ambient air temperature for heat pump water heaters to be 
67\1/2\ deg.F  1 deg.F (19.7 deg.C  0.6 deg.C) 
and for all other water heater types to be between 65 deg. F 
(18.3 deg.C) and 70 deg. F (21.1 deg.C) . DOE did not propose a change 
to these values. EPRI stated that the existing ambient air temperature 
values are satisfactory, but suggested using a nationwide survey to 
determine more representative ambient air temperature values. (EPRI, 
No. 56. at 5.) DOE believes a survey is unnecessary and will continue 
to use the current values.
    d. Supply Water Temperature. The current DOE test procedure 
specifies supply water temperature to be 58 deg.F  2 deg.F 
(14.4 deg.C  1.1 deg.C). DOE did not propose a change to 
this value. EPRI stated that the existing supply water temperature 
value is satisfactory, but suggested revisiting the value periodically 
because of the possible change of the average source temperature caused 
by regional shifts in the population. (EPRI, No. 56 at 5 and 6.) DOE 
believes the current value for supply water temperature is appropriate 
and that changing it would place an unreasonable burden on 
manufacturers.
    e. Relative Humidity. The current DOE test procedure specifies 
relative humidity for heat pump water heaters to be between 49% and 
51%. DOE did not propose a change to this value. EPRI stated that the 
existing humidity value is satisfactory, but suggested using weighted 
regional averages in the future to account for humidity extremes. 
(EPRI, No. 56 at 5 and 6.) DOE believes the current value for humidity 
is appropriate and that changing it would place an unreasonable burden 
on manufacturers.
8. Cost-Based Correction Factor for Fossil-Fueled Residential 
Appliances
    The current procedure provides a test method to measure the energy 
efficiency of water heaters that is used to rate units of similar 
volumes for comparison purposes. This measure of energy efficiency is 
known as the energy factor (EF). DOE did not propose any amendment to 
the existing test method in the Proposed Rule.
    AGA commented that because the energy factor is calculated from 
measurements of the consumption of energy at the site, the EF for 
fossil-fueled water heaters is substantially lower than the EF for 
electric water heaters. AGA also stated that gas-fired water heaters 
typically cost consumers considerably less to operate. AGA stated

[[Page 26007]]

that there is no correlation between the current energy descriptor and 
the cost of operation. AGA believes this inconsistency between the 
energy descriptor and cost of operation can be extremely misleading to 
the consumer if a purchase decision is based primarily on the energy 
factor or annual energy consumption. Therefore, AGA suggested that the 
energy usage of the water heater be adjusted by a multiplication factor 
of 0.298 which represents the ratio of the average cost of fossil fuel 
to electricity. (AGA, No. 25 at 5.)
    The 0.298 factor is the inverse of DOE's F-factor of 3.36 which was 
proposed in the furnaces/boilers, vented home heating equipment and 
pool heaters test procedures. The F-factor would have allowed the 
consumption of fossil fuel and electricity to be combined into a single 
value by placing the two energy types on a common basis. (60 FR 4348, 
January 20, 1995.)
    In response to disagreement from an overwhelming majority of 
commenters regarding the proposed F-factor, the Department stated that 
the Energy Policy and Conservation Act, as amended, requires the energy 
efficiency of a furnace to be based on consumption of energy at the 
site per the definition of ``energy use,'' 42 U.S.C. 6291(4). The 
Department also concluded that the statute does not permit the 
promulgation of an energy efficiency standard that is expressed in 
terms of annual operating costs of the furnace. Based on this analysis, 
the Department withdrew the proposed F-Factor in its Final Rule 
Regarding Test Procedures for Furnaces/Boilers, Vented Home Heating 
Equipment and Pool Heaters. (62 FR 26140, May 12, 1997.) Likewise, DOE 
will not adjust the energy factor for electric water heaters to a 
source basis as proposed by AGA.

III. Procedural Requirements

A. Review Under the National Environmental Policy Act of 1969

    In this rule, the Department will finalize amendments to test 
procedures that may be used to implement future energy conservation 
standards for water heaters. The Department has determined that this 
rule falls into a class of actions that are categorically excluded from 
review under the National Environmental Policy Act of 1969 (NEPA), 42 
U.S.C. 4321 et seq. The rule is covered by Categorical Exclusion A5, 
for rulemakings that interpret or amend an existing rule without 
changing the environmental effect, as set forth in the Department's 
NEPA regulations at Appendix A to Subpart D, 10 CFR part 1021. This 
Final Rule will not affect the quality or distribution of energy usage 
and, therefore, will not result in any environmental impacts. 
Accordingly, neither an environmental impact statement nor an 
environmental assessment is required.

B. Review Under Executive Order 12866, ``Regulatory Planning and 
Review'

    Today's Final Rule is not a ``significant regulatory action'' under 
Executive Order 12866, ``Regulatory Planning and Review.'' 58 FR 51735 
(October 4, 1993). Accordingly, today's action is not subject to review 
under the Executive Order by the Office of Information and Regulatory 
Affairs.

C. Review Under the Regulatory Flexibility Act of 1980

    The Regulatory Flexibility Act of 1980, 5 U.S.C. 601-612, requires 
that an agency prepare an initial regulatory flexibility analysis for 
any rule, for which a general notice of proposed rulemaking is 
required, that would have a significant economic effect on small 
entities unless the agency certifies that the rule, if promulgated, 
will not have a significant economic impact on a substantial number of 
small entities. 5 U.S.C. 605. DOE certified in the notice of proposed 
rulemaking that the rule would not have a significant economic impact 
on a substantial number of small entities. DOE estimates there are 
approximately 7 manufacturers of water heaters for specialty markets 
that may be small entities as defined in the Regulatory Flexibility 
Act. The manufacturers of heat pump water heaters and storage-type 
water heaters already make the types of measurements required by this 
rule, and the cost of compliance will be negligible. Today's revised 
test procedures will have no immediate impact on manufacturers of 
instantaneous water heaters because there currently are no energy 
efficiency standards for instantaneous water heaters; in any event, the 
cost of compliance would not be significant. DOE received no comments 
on its certification in the proposed rule.

D. ``Takings'' Assessment Review

    DOE has determined pursuant to Executive Order 12630, 
``Governmental Actions and Interference with Constitutionally Protected 
Property Rights,'' 53 FR 8859 (March 18, 1988), that this regulation, 
if adopted, would not result in any takings which might require 
compensation under the Fifth Amendment to the United States 
Constitution.

E. Federalism Review

    Executive Order 12612, ``Federalism,'' 52 FR 41685 (October 30, 
1987), requires that regulations, rules, legislation, and any other 
policy actions be reviewed for any substantial direct effects on 
States, on the relationship between the Federal Government and the 
States, or in the distribution of power and responsibilities among 
various levels of Government. If there are substantial direct effects, 
then this Executive Order requires preparation of a Federalism 
assessment to be used in all decisions involved in promulgating and 
implementing a policy action.
    The Final Rule published today would not regulate the States. 
Accordingly, DOE has determined that preparation of a Federalism 
assessment is unnecessary.

F. Review Under the Paperwork Reduction Act

    No new information or record keeping requirements are imposed by 
this rulemaking. Accordingly, no OMB clearance is required under the 
Paperwork Reduction Act, 44 U.S.C. 3501 et seq.

G. Review Under Executive Order 12988, ``Civil Justice Reform''

    With respect to the review of existing regulations and the 
promulgation of new regulations, section 3(a) of Executive Order 12988, 
``Civil Justice Reform,'' 61 FR 4729 (February 7, 1996), imposes on 
executive agencies the following requirements: (1) Eliminate drafting 
errors and ambiguity; (2) write regulations to minimize litigation; and 
(3) provide a clear legal standard for affected conduct rather than a 
general standard and promote simplification and burden reduction. With 
regard to the review required by sections 3(a) and 3(b) of the 
Executive Order specifically requires that Executive agencies make 
every reasonable effort to ensure that the regulation: (1) Clearly 
specifies the preemptive effect, if any; (2) clearly specifies any 
effect on existing Federal law or regulation; (3) provides a clear 
legal standard for affected conduct while promoting simplification and 
reducing burdens; (4) specifies the retroactive effect, if any; (5) 
adequately defines key terms; and (6) addresses other important issues 
affecting clarity and general draftsmanship under any guidelines issued 
by the Attorney General. Section 3(c) of the Executive Order requires 
Executive agencies to review regulations in light of applicable 
standards in sections 3(a) and 3(b) to determine whether they are met 
or it is unreasonable to meet one or more of

[[Page 26008]]

them. DOE reviewed today's rule under the standards of section 3 of the 
Executive Order and determined that, to the extent permitted by law, it 
meets the requirements of those standards.

H. Review Under the Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995, 2 U.S.C. 1531 
et seq., requires each Federal agency, to the extent permitted by law, 
to prepare a written assessment of the effects of any Federal mandate 
in a final agency rule that may result in the expenditure by State, 
local, and tribal governments, in the aggregate, or by the private 
sector, of $100 million or more (adjusted annually for inflation) in 
one year.
    The Department has determined that this Final Rule does not include 
any requirements that would result in the expenditure of money by 
State, local, and tribal governments. It also would not result in costs 
to the private sector of $100 million or more in any one year. 
Therefore, the requirements of the Unfunded Mandates Reform Act of 1995 
do not apply to this rulemaking.

I. Congressional Notification

    Consistent with Subtitle E of the Small Business Regulatory 
Enforcement Fairness Act of 1996, 5 U.S.C. 801-808, DOE will submit to 
Congress a report regarding the issuance of today's Final Rule prior to 
the effective date set forth at the outset of this notice. The report 
will note the Office of Management and Budget's determination that this 
rule does not constitute a ``major rule'' under that Act. 5 U.S.C. 801, 
804.

List of Subjects in 10 CFR Part 430

    Administrative practice and procedure, Energy conservation, 
Household appliances.

    Issued in Washington, D.C., on April 6, 1998.
Dan W. Reicher,
Assistant Secretary, Energy Efficiency and Renewable Energy.

    For the reasons set forth in the preamble, Part 430 of Chapter II 
of Title 10 of the Code of Federal Regulations is amended as set forth 
below:

PART 430--ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS

    1. The authority citation for Part 430 continues to read as 
follows:

    Authority: Part B, Title III, Energy Policy and Conservation 
Act, (42 U.S.C. 6291-6309), as amended.

    2. Appendix E to Subpart B of Part 430 is revised to read as 
follows:

Appendix E to Subpart B of Part 430--Uniform Test Method for Measuring 
the Energy Consumption of Water Heaters

1. Definitions

    1.1  Cut-in means the time when or water temperature at which a 
water heater control or thermostat acts to increase the energy or 
fuel input to the heating elements, compressor, or burner.
    1.2  Cut-out means the time when or water temperature at which a 
water heater control or thermostat acts to reduce to a minimum the 
energy or fuel input to the heating elements, compressor, or burner.
    1.3  Design Power Rating means the nominal power rating that a 
water heater manufacturer assigns to a particular design of water 
heater, expressed in kilowatts or Btu (kJ) per hour as appropriate.
    1.4  Energy Factor means a measure of water heater overall 
efficiency.
    1.5  First-Hour Rating means an estimate of the maximum volume 
of ``hot'' water that a storage-type water heater can supply within 
an hour that begins with the water heater fully heated (i.e., with 
all thermostats satisfied). It is a function of both the storage 
volume and the recovery rate.
    1.6  Heat Trap means a device which can be integrally connected 
or independently attached to the hot and/or cold water pipe 
connections of a water heater such that the device will develop a 
thermal or mechanical seal to minimize the recirculation of water 
due to thermal convection between the water heater tank and its 
connecting pipes.
    1.7  Instantaneous Water Heaters
    1.7.1  Electric Instantaneous Water Heater Reserved.
    1.7.2  Gas Instantaneous Water Heater means a water heater that 
uses gas as the energy source, initiates heating based on sensing 
water flow, is designed to deliver water at a controlled temperature 
of less than 180 deg.F (82 deg.C), has an input greater than 50,000 
Btu/h (53 MJ/h) but less than 200,000 Btu/h (210 MJ/h), and has a 
manufacturer's specified storage capacity of less than 2 gallons 
(7.6 liters). The unit may use a fixed or variable burner input.
    1.8  Maximum gpm (L/min) Rating means the maximum gallons per 
minute (liters per minute) of hot water that can be supplied by an 
instantaneous water heater while maintaining a nominal temperature 
rise of 77 deg.F (42.8 deg.C) during steady state operation.
    1.9  Rated Storage Volume means the water storage capacity of a 
water heater, in gallons (liters), as specified by the manufacturer.
    1.10  Recovery Efficiency means the ratio of energy delivered to 
the water to the energy content of the fuel consumed by the water 
heater.
    1.11  Standby means the time during which water is not being 
withdrawn from the water heater. There are two standby time 
intervals used within this test procedure: 
stby,1 represents the elapsed time between the 
time at which the maximum mean tank temperature is observed after 
the sixth draw and subsequent recovery and the end of the 24-hour 
test; stby,2 represents the total time during 
the 24-hour simulated use test when water is not being withdrawn 
from the water heater.
    1.12  Storage-type Water Heaters
    1.12.1  Electric Storage-type Water Heater means a water heater 
that uses electricity as the energy source, is designed to heat and 
store water at a thermostatically controlled temperature of less 
than 180 deg.F (82 deg.C), has a nominal input of 12 kilowatts 
(40,956 Btu/h) or less, and has a rated storage capacity of not less 
than 20 gallons (76 liters) nor more than 120 gallons (450 liters).
    1.12.2  Gas Storage-type Water Heater means a water heater that 
uses gas as the energy source, is designed to heat and store water 
at a thermostatically controlled temperature of less than 180 deg.F 
(82 deg.C), has a nominal input of 75,000 Btu (79 MJ) per hour or 
less, and has a rated storage capacity of not less than 20 gallons 
(76 liters) nor more than 100 gallons (380 liters).
    1.12.3  Heat Pump Water Heater means a water heater that uses 
electricity as the energy source, is designed to heat and store 
water at a thermostatically controlled temperature of less than 
180 deg.F (82 deg.C), has a maximum current rating of 24 amperes 
(including the compressor and all auxiliary equipment such as fans, 
pumps, controls, and, if on the same circuit, any resistive 
elements) for an input voltage of 250 volts or less, and, if the 
tank is supplied, has a manufacturer's rated storage capacity of 120 
gallons (450 liters) or less. Resistive elements used to provide 
supplemental heating may use the same circuit as the compressor if 
(1) an interlocking mechanism prevents concurrent compressor 
operation and resistive heating or (2) concurrent operation does not 
result in the maximum current rating of 24 amperes being exceeded. 
Otherwise, the resistive elements and the heat pump components must 
use separate circuits. A heat pump water heater may be sold by the 
manufacturer with or without a storage tank.
    a. Heat Pump Water Heater with Storage Tank means an air-to-
water heat pump sold by the manufacturer with an insulated storage 
tank as a packaged unit. The tank and heat pump can be an integral 
unit or they can be separated.
    b. Heat Pump Water Heater without Storage Tank (also called Add-
on Heat Pump Water Heater) means an air-to-water heat pump designed 
for use with a storage-type water heater or a storage tank that is 
not specified or supplied by the manufacturer.
    1.12.4  Oil Storage-type Water Heater means a water heater that 
uses oil as the energy source, is designed to heat and store water 
at a thermostatically controlled temperature of less than 180 deg.F 
(82 deg.C), has a nominal energy input of 105,000 Btu/h (110 MJ/h) 
or less, and has a manufacturer's rated storage capacity of 50 
gallons (190 liters) or less.
    1.12.5  Storage-type Water Heater of More than 2 Gallons (7.6 
Liters) and Less than 20 Gallons (76 Liters). Reserved.
    1.13  ASHRAE Standard 41.1-86 means the standard published in 
1986 by the American Society of Heating, Refrigerating and Air-
Conditioning Engineers, Inc., and titled Standard Measurement Guide: 
Section on Temperature Measurements.
    1.14  ASTM-D-2156-80 means the test standard published in 1980 
by the American

[[Page 26009]]

Society for Testing and Measurements and titled ``Smoke Density in 
Flue Gases from Burning Distillate Fuels, Test Method for''.
    1.15  Symbol Usage The following identity relationships are 
provided to help clarify the symbology used throughout this 
procedure:

Cp specific heat capacity of water
Eannual annual energy consumption of a water heater
Ef energy factor of a water heater
Fhr first-hour rating of a storage-type water heater
Fmax maximum gpm (L/min) rating of an instantaneous water 
heater rated at a temperature rise of 77 deg.F (42.8 deg.C) across 
the heater
i a subscript to indicate an ith draw during a test
Mi mass of water removed during the ith draw (i=1 to 6) 
of the 24-hr simulated use test
M*i for storage-type water heaters, mass of water removed 
during the ith draw (i=1 to n) during the first-hour rating test
M10m for instantaneous water heaters, mass of water 
removed continuously during a 10-minute interval in the maximum gpm 
(L/min) rating test
n for storage-type water heaters, total number of draws during the 
first-hour rating test
Q total fossil fuel and/or electric energy consumed during the 
entire 24-hr simulated use test
Qd daily water heating energy consumption adjusted for 
net change in internal energy
Qda adjusted daily water heating energy consumption with 
adjustment for variation of tank to ambient air temperature 
difference from nominal value
Qdm overall adjusted daily water heating energy 
consumption including Qda and QHWD
Qhr hourly standby losses
QHW daily energy consumption to heat water over the 
measured average temperature rise across the water heater
QHWD adjustment to daily energy consumption, 
Qhw, due to variation of the temperature rise across the 
water heater not equal to the nominal value of 77 deg.F (42.8 deg.C)
Qr energy consumption of fossil fuel or heat pump water 
heaters between thermostat (or burner) cut-out prior to the first 
draw and cut-out following the first draw of the 24-hr simulated use 
test
Qr, max energy consumption of a modulating instantaneous 
water heater between cut-out (burner) prior to the first draw and 
cut-out following the first draw of the 24-hr simulated use test
Qr, min energy consumption of a modulating instantaneous 
water heater from immediately prior to the fourth draw to burner 
cut-out following the fourth draw of the 24-hr simulated use test
Qstby total energy consumed by the water heater during 
the standby time interval 
, 1
Qsu total fossil fueled and/or electric energy consumed 
from the beginning of the first draw to the thermostat (or burner) 
cut-out following the completion of the sixth draw during the 24-hr 
simulated use test
Tmin for modulating instantaneous water heaters, steady 
state outlet water temperature at the minimum fuel input rate
T0 mean tank temperature at the beginning of the 24-hr 
simulated use test
T24 mean tank temperature at the end of the 24-hr 
simulated use test
Ta, stby average ambient air temperature during standby 
periods of the 24-hr use test
Tdel for instantaneous water heaters, average outlet 
water temperature during a 10-minute continuous draw interval in the 
maximum gpm (L/min) rating test
Tdel, i average outlet water temperature during the ith 
draw of the 24-hr simulated use test
Tin for instantaneous water heaters, average inlet water 
temperature during a 10-minute continuous draw interval in the 
maximum gpm (L/min) rating test
Tin, i average inlet water temperature during the ith 
draw of the 24-hr simulated use test
Tmax, 1 maximum measured mean tank temperature after cut-
out following the first draw of the 24-hr simulated use test
Tstby average storage tank temperature during the standby 
period , 2 
of the 24-hr use test
Tsu maximum measured mean tank temperature after cut-out 
following the sixth draw of the 24-hr simulated use test
Tt, stby average storage tank temperature during the 
standby period , 1 of the 24-hr use 
test
T*del, i for storage-type water heaters, average outlet 
water temperature during the ith draw (i=1 to n) of the first-hour 
rating test
T*max, i for storage-type water heaters, maximum outlet 
water temperature observed during the ith draw (i=1 to n) of the 
first-hour rating test
T*min, i for storage-type water heaters, minimum outlet 
water temperature to terminate the ith draw during the first-hour 
rating test
UA standby loss coefficient of a storage-type water heater
Vi volume of water removed during the ith draw (i=1 to 6) 
of the 24-hr simulated use test
V* i volume of water removed during the ith draw (i=1 to 
n) during the first-hour rating test
V10m for instantaneous water heaters, volume of water 
removed continuously during a 10-minute interval in the maximum gpm 
(L/min) rating test
Vmax steady state water flow rate of an instantaneous 
water heater at the rated input to give a discharge temperature of 
135 deg.F  5 deg.F (57.2 deg.C  2.8 deg.C)
Vmin steady state water flow rate of a modulating 
instantaneous water heater at the minimum input to give a discharge 
temperature of Tmin up to 135 deg.F  5 deg.F 
(57.2 deg.C  2.8 deg.C)
Vst measured storage volume of the storage tank
Wf weight of storage tank when completely filled with 
water
Wt tare weight of storage tank when completely empty of 
water
nr recovery efficiency
p density of water
, 1 elapsed 
time between the time the maximum mean tank temperature is observed 
after the sixth draw and the end of the 24-hr simulated use test
, 2 overall 
standby periods when no water is withdrawn during the 24-hr 
simulated use test

2. Test Conditions

    2.1  Installation Requirements. Tests shall be performed with 
the water heater and instrumentation installed in accordance with 
Section 4 of this appendix.
    2.2  Ambient Air Temperature. The ambient air temperature shall 
be maintained between 65.0 deg.F and 70.0 deg.F (18.3 deg.C and 
21.1 deg.C) on a continuous basis. For heat pump water heaters, the 
dry bulb temperature shall be maintained at 67.5 deg.F  
1 deg.F (19.7 deg.C  0.6 deg.C) and, in addition, the 
relative humidity shall be maintained between 49% and 51%.
    2.3  Supply Water Temperature. The temperature of the water 
being supplied to the water heater shall be maintained at 58 deg.F 
 2 deg.F (14.4 deg.C  1.1 deg.C) throughout 
the test.
    2.4  Storage Tank Temperature. The average temperature of the 
water within the storage tank shall be set to 135 deg.F  
5 deg.F (57.2 deg.C  2.8 deg.C).
    2.5  Supply Water Pressure. During the test when water is not 
being withdrawn, the supply pressure shall be maintained between 40 
psig (275 kPa) and the maximum allowable pressure specified by the 
water heater manufacturer.
    2.6  Electrical and/or Fossil Fuel Supply.
    2.6.1  Electrical. Maintain the electrical supply voltage to 
within  1% of the center of the voltage range specified 
by the water heater and/or heat pump manufacturer.
    2.6.2  Natural Gas. Maintain the supply pressure in accordance 
with the manufacturer's specifications. If the supply pressure is 
not specified, maintain a supply pressure of 7-10 inches of water 
column (1.7-2.5 kPa). If the water heater is equipped with a gas 
appliance pressure regulator, the regulator outlet pressure shall be 
within  10% of the manufacturer's specified manifold 
pressure. For all tests, use natural gas having a heating value of 
approximately 1,025 Btu per standard cubic foot (38,190 kJ per 
standard cubic meter).
    2.6.3  Propane Gas. Maintain the supply pressure in accordance 
with the manufacturer's specifications. If the supply pressure is 
not specified, maintain a supply pressure of 11-13 inches of water 
column (2.7-3.2 kPa). If the water heater is equipped with a gas 
appliance pressure regulator, the regulator outlet pressure shall be 
within  10% of the manufacturer's specified manifold 
pressure. For all tests, use propane gas with a heating value of 
approximately 2,500 Btu per standard cubic foot (93,147 kJ per 
standard cubic meter).
    2.6.4  Fuel Oil Supply. Maintain an uninterrupted supply of fuel 
oil. Use fuel oil

[[Page 26010]]

having a heating value of approximately 138,700 Btu per gallon 
(38,660 kJ per liter).

3. Instrumentation

    3.1  Pressure Measurements. Pressure-measuring instruments shall 
have an error no greater than the following values:

------------------------------------------------------------------------
        Item measured          Instrument accuracy  Instrument precision
------------------------------------------------------------------------
Gas pressure................   0.1       0.05   
                               inch of water         inch of water      
                               column ( 0.025 kPa).    minus> 0.012 kPa). 
Atmospheric pressure........   0.1       0.05   
                               inch of mercury       inch of mercury    
                               column ( 0.34 kPa).     minus> 0.17 kPa).  
Water pressure..............   1.0       0.50   
                               pounds per square     pounds per square  
                               inch (    inch ( 
                               6.9 kPa).             3.45 kPa).         
------------------------------------------------------------------------

    3.2  Temperature Measurement
    3.2.1  Measurement. Temperature measurements shall be made in 
accordance with the Standard Measurement Guide: Section on 
Temperature Measurements, ASHRAE Standard 41.1-86.
    3.2.2  Accuracy and Precision. The accuracy and precision of the 
instruments, including their associated readout devices, shall be 
within the following limits:

----------------------------------------------------------------------------------------------------------------
            Item measured                   Instrument accuracy                  Instrument precision           
----------------------------------------------------------------------------------------------------------------
Air dry bulb temperature.............   0.2 deg.F ( 0.1 deg.F ( 0.06 
                                        minus> 0.1 deg.C).             deg.C)                                   
Air wet bulb temperature.............   0.2 deg.F ( 0.1 deg.F ( 0.06 
                                        minus> 0.1 deg.C).             deg.C)                                   
Inlet and outlet water temperatures..   0.2 deg.F ( 0.1 deg.F ( 0.06 
                                        minus> 0.1 deg.C).             deg.C)                                   
Storage tank temperatures............   0.5 deg.F ( 0.25 deg.F ( 0.14
                                        minus> 0.3 deg.C).             deg.C)                                   
----------------------------------------------------------------------------------------------------------------

    3.2.3  Scale Division. In no case shall the smallest scale 
division of the instrument or instrument system exceed 2 times the 
specified precision.
    3.2.4  Temperature Difference. Temperature difference between 
the entering and leaving water may be measured with any of the 
following:

a. A thermopile
b. Calibrated resistance thermometers
c. Precision thermometers
d. Calibrated thermistors
e. Calibrated thermocouples
f. Quartz thermometers

    3.2.5  Thermopile Construction. If a thermopile is used, it 
shall be made from calibrated thermocouple wire taken from a single 
spool. Extension wires to the recording device shall also be made 
from that same spool.
    3.2.6  Time Constant. The time constant of the instruments used 
to measure the inlet and outlet water temperatures shall be no 
greater than 5 seconds.
    3.3  Liquid Flow Rate Measurement. The accuracy of the liquid 
flow rate measurement, using the calibration if furnished, shall be 
equal to or less than  1% of the measured value in mass 
units per unit time.
    3.4  Electric Energy. The electrical energy used shall be 
measured with an instrument and associated readout device that is 
accurate within  1% of the reading.
    3.5  Fossil Fuels. The quantity of fuel used by the water heater 
shall be measured with an instrument and associated readout device 
that is accurate within  1% of the reading.
    3.6  Mass Measurements. For mass measurements greater than or 
equal to 10 pounds (4.5 kg), a scale that is accurate within 
 1% of the reading shall be used to make the 
measurement. For mass measurements less than 10 pounds (4.5 kg), the 
scale shall provide a measurement that is accurate within 
 0.1 pound (0.045 kg).
    3.7  Heating Value. The higher heating value of the natural gas, 
propane, or fuel oil shall be measured with an instrument and 
associated readout device that is accurate within  1% of 
the reading. The heating value of natural gas and propane must be 
corrected for local temperature and pressure conditions.
    3.8  Time. The elapsed time measurements shall be measured with 
an instrument that is accurate within  0.5 seconds per 
hour.
    3.9  Volume. Volume measurements shall be measured with an 
accuracy of  2% of the total volume.

4. Installation

    4.1  Water Heater Mounting. A water heater designed to be 
freestanding shall be placed on a \3/4\ inch (2 cm) thick plywood 
platform supported by three 2  x  4 inch (5 cm  x  10 cm) runners. 
If the water heater is not approved for installation on combustible 
flooring, suitable non-combustible material shall be placed between 
the water heater and the platform. Counter-top water heaters shall 
be placed against a simulated wall section. Wall-mounted water 
heaters shall be supported on a simulated wall in accordance with 
the manufacturer-published installation instructions. When a 
simulated wall is used, the recommended construction is 2  x  4 inch 
(5 cm  x  10 cm) studs, faced with \3/4\ inch (2 cm) plywood. For 
heat pump water heaters that are supplied with a storage tank, the 
two components, if not delivered as a single package, shall be 
connected in accordance with the manufacturer-published installation 
instructions and the overall system shall be placed on the above-
described plywood platform. If installation instructions are not 
provided by the heat pump manufacturer, uninsulated 8 foot (2.4 m) 
long connecting hoses having an inside diameter of \5/8\ inch (1.6 
cm) shall be used to connect the storage tank and the heat pump 
water heater. With the exception of using the storage tank described 
in 4.10, the same requirements shall apply for heat pump water 
heaters that are supplied without a storage tank from the 
manufacturer. The testing of the water heater shall occur in an area 
that is protected from drafts.
    4.2  Water Supply. Connect the water heater to a water supply 
capable of delivering water at conditions as specified in Sections 
2.3 and 2.5 of this appendix.
    4.3  Water Inlet and Outlet Configuration. For freestanding 
water heaters that are taller than 36 inches (91.4 cm), inlet and 
outlet piping connections shall be configured in a manner consistent 
with Figures 1 and 2. Inlet and outlet piping connections for wall-
mounted water heaters shall be consistent with Figure 3. For 
freestanding water heaters that are 36 inches or less in height and 
not supplied as part of a counter-top enclosure (commonly referred 
to as an under-the-counter model), inlet and outlet piping shall be 
installed in a manner consistent with Figures 4, 5, and 6. For water 
heaters that are supplied with a counter-top enclosure, inlet and 
outlet piping shall be made in a manner consistent with Figures 7A 
and 7B, respectively. The vertical piping noted in Figures 7A and 7B 
shall be located (whether inside the enclosure or along the outside 
in a recessed channel) in accordance with the manufacturer-published 
installation instructions.
    All dimensions noted in Figures 1 through 7 shall be achieved. 
All piping between the water heater and the inlet and outlet 
temperature sensors, noted as TIN and TOUT in 
the figures, shall be Type ``L'' hard copper having the same 
diameter as the connections on the water heater. Unions may be used 
to facilitate installation and removal of the piping arrangements. A 
pressure gauge and diaphragm expansion tank shall be installed in 
the supply water piping at a location upstream of the inlet 
temperature sensor. An appropriately rated pressure and temperature 
relief valve shall be installed on all water heaters at the port 
specified by the manufacturer. Discharge piping for the relief valve 
shall be non-metallic. If heat traps, piping insulation, or pressure 
relief valve insulation are supplied with the water heater, they 
shall be installed for testing. Except when using a simulated wall, 
clearance shall be provided such that none of the piping contacts 
other surfaces in the test room.
    4.4  Fuel and/or Electrical Power and Energy Consumption. 
Install one or more

[[Page 26011]]

instruments which measure, as appropriate, the quantity and rate of 
electrical energy and/or fossil fuel consumption in accordance with 
Section 3. For heat pump water heaters that use supplemental 
resistive heating, the electrical energy supplied to the resistive 
element(s) shall be metered separately from the electrical energy 
supplied to the entire appliance or to the remaining components 
(e.g., compressor, fans, pumps, controls).
    4.5  Internal Storage Tank Temperature Measurements. Install six 
temperature measurement sensors inside the water heater tank with a 
vertical distance of at least 4 inches (100 mm) between successive 
sensors. A temperature sensor shall be positioned at the vertical 
midpoint of each of the six equal volume nodes within the tank. 
Nodes designate the equal volumes used to evenly partition the total 
volume of the tank. As much as is possible, the temperature sensor 
should be positioned away from any heating elements, anodic 
protective devices, tank walls, and flue pipe walls. If the tank 
cannot accommodate six temperature sensors and meet the installation 
requirements specified above, install the maximum number of sensors 
which comply with the installation requirements. The temperature 
sensors shall be installed either through (1) the anodic device 
opening; (2) the relief valve opening; or (3) the hot water outlet. 
If installed through the relief valve opening or the hot water 
outlet, a tee fitting or outlet piping, as applicable, shall be 
installed as close as possible to its original location. If the 
relief valve temperature sensor is relocated, and it no longer 
extends into the top of the tank, a substitute relief valve that has 
a sensing element that can reach into the tank shall be installed. 
If the hot water outlet includes a heat trap, the heat trap shall be 
installed on top of the tee fitting. Added fittings shall be covered 
with thermal insulation having an R value between 4 and 8 
hft2 deg.F/Btu (0.7 and 1.4 
m2 deg.C/W).
    4.6  Ambient Air Temperature Measurement. Install an ambient air 
temperature sensor at the vertical mid-point of the water heater and 
approximately 2 feet (610 mm) from the surface of the water heater. 
The sensor shall be shielded against radiation.
    4.7  Inlet and Outlet Water Temperature Measurements. Install 
temperature sensors in the cold-water inlet pipe and hot-water 
outlet pipe as shown in Figures 1, 2, 3, 4, 5, 6, 7a and 7b, as 
applicable.
    4.8  Flow Control. A valve shall be installed to provide flow as 
specified in sections 5.1.4.1 for storage tank water heaters and 
5.2.1 for instantaneous water heaters.
    4.9  Flue Requirements.
    4.9.1  Gas-Fired Water Heaters. Establish a natural draft in the 
following manner. For gas-fired water heaters with a vertically 
discharging draft hood outlet, a 5-foot (1.5-meter) vertical vent 
pipe extension with a diameter equal to the largest flue collar size 
of the draft hood shall be connected to the draft hood outlet. For 
gas-fired water heaters with a horizontally discharging draft hood 
outlet, a 90-degree elbow with a diameter equal to the largest flue 
collar size of the draft hood shall be connected to the draft hood 
outlet. A 5-foot (1.5-meter) length of vent pipe shall be connected 
to the elbow and oriented to discharge vertically upward. Direct 
vent gas-fired water heaters shall be installed with venting 
equipment specified in the manufacturer's instructions using the 
minimum vertical and horizontal lengths of vent pipe recommended by 
the manufacturer.
    4.9.2  Oil-Fired Water Heaters. Establish a draft at the flue 
collar at the value specified in the manufacturer's instructions. 
Establish the draft by using a sufficient length of vent pipe 
connected to the water heater flue outlet, and directed vertically 
upward. For an oil-fired water heater with a horizontally 
discharging draft hood outlet, a 90-degree elbow with a diameter 
equal to the largest flue collar size of the draft hood shall be 
connected to the draft hood outlet. A length of vent pipe sufficient 
to establish the draft shall be connected to the elbow fitting and 
oriented to discharge vertically upward. Direct-vent oil-fired water 
heaters should be installed with venting equipment as specified in 
the manufacturer's instructions, using the minimum vertical and 
horizontal lengths of vent pipe recommended by the manufacturer.
    4.10  Heat Pump Water Heater Storage Tank. The tank to be used 
for testing a heat pump water heater without a tank supplied by the 
manufacturer (see Section 1.12.3b) shall be an electric storage-type 
water heater having a measured volume of 47.0 gallons 
1.0 gallon (178 liters 3.8 liters); two 4.5 
kW heating elements controlled in such a manner as to prevent both 
elements from operating simultaneously; and an energy factor greater 
than or equal to the minimum energy conservation standard (as 
determined in accordance with Section 6.1.7) and less than or equal 
to the sum of the minimum energy conservation standard and 0.02.

5. Test Procedures

    5.1  Storage-type Water Heaters, Including Heat Pump Water 
Heaters.
    5.1.1  Determination of Storage Tank Volume. Determine the 
storage capacity, Vst, of the water heater under test, in 
gallons (liters), by subtracting the tare weight--measured while the 
tank is empty--from the gross weight of the storage tank when 
completely filled with water (with all air eliminated and line 
pressure applied as described in section 2.5) and dividing the 
resulting net weight by the density of water at the measured 
temperature.
    5.1.2  Setting the Thermostat.
    5.1.2.1  Single Thermostat Tanks. Starting with a tank at the 
supply water temperature, initiate normal operation of the water 
heater. After cut-out, determine the mean tank temperature every 
minute until the maximum value is observed. Determine whether this 
maximum value for the mean tank temperature is within the range of 
135 deg.F5 deg.F (57.2 deg.C2.8 deg.C). If 
not, turn off the water heater, adjust the thermostat, drain and 
refill the tank with supply water. Then, once again, initiate normal 
operation of the water heater, and determine the maximum mean tank 
temperature after cut-out. Repeat this sequence until the maximum 
mean tank temperature after cut-out is 135 deg.F5 deg.F 
(57.2 deg.C2.8 deg.C).
    5.1.2.2  Tanks with Two or More Thermostats. Follow the same 
sequence as for a single thermostat tank, i.e. start at the supply 
water temperature, operate normally until cutout. Determine if the 
thermostat that controls the uppermost heating element yields a 
maximum water temperature of 135 deg.F5 deg.F 
(57.2 deg.C2.8 deg.C), as measured by the in-tank 
sensors that are positioned above the uppermost heating element. If 
the tank temperature at the thermostat is not within 
135 deg.F5 deg.F (57.2 deg.C2.8 deg.C), turn 
off the water heater, adjust the thermostat, drain and refill the 
tank with supply water. The thermostat that controls the heating 
element positioned next highest in the tank shall then be set to 
yield a maximum water temperature of 135 deg.F5 deg.F 
(57.2 deg.C2.8 deg.C). This process shall be repeated 
until the thermostat controlling the lowest element is correctly 
adjusted. When adjusting the thermostat that controls the lowest 
element, the maximum mean tank temperature after cut-out, as 
determined using all the in-tank sensors, shall be 
135 deg.F5 deg.F (57.2 deg.C2.8 deg.C). When 
adjusting all other thermostats, use only the in-tank temperature 
sensors positioned above the heating element in question to evaluate 
the maximum water temperature after cut-out.
    For heat pump water heaters that control an auxiliary resistive 
element, the thermostat shall be set in accordance with the 
manufacturer's installation instructions.
    5.1.3  Power Input Determination. For all water heaters except 
electric types having immersed heating elements, initiate normal 
operation and determine the power input, P, to the main burners 
(including pilot light power, if any) after 15 minutes of operation. 
If the water heater is equipped with a gas appliance pressure 
regulator, the regulator outlet pressure shall be set within 
 10% of that recommended by the manufacturer. For oil-
fired water heaters the fuel pump pressure shall be within 
 10% of the manufacturer's specified pump pressure. All 
burners shall be adjusted to achieve an hourly Btu (kJ) rating that 
is within  2% of the value specified by the 
manufacturer. For an oil-fired water heater, adjust the burner to 
give a CO2 reading recommended by the manufacturer and an 
hourly Btu (kJ) rating that is within  2% of that 
specified by the manufacturer. Smoke in the flue may not exceed No. 
1 smoke as measured by the procedure in ASTM-D-2156-80.
    5.1.4  First-Hour Rating Test.
    5.1.4.1  General. During hot water draws, remove water at a rate 
of 3.00.25 gallons per minute (11.40.95 
liters per minute). Collect the water in a container that is large 
enough to hold the volume removed during an individual draw and 
suitable for weighing at the termination of each draw. 
Alternatively, a water meter may be used to directly measure the 
water volume(s) withdrawn.
    5.1.4.2  Draw Initiation Criteria. Begin the first-hour rating 
test by imposing a draw on the storage-type water heater. After 
completion of this first draw, initiate successive draws based on 
the following criteria. For gas-and oil-fired water heaters, 
initiate successive draws when the thermostat acts to reduce the 
supply of fuel to the main burner. For electric water heaters having 
a single element or multiple elements that all operate 
simultaneously, initiate

[[Page 26012]]

successive draws when the thermostat acts to reduce the electrical 
input supplied to the element(s). For electric water heaters having 
two or more elements that do not operate simultaneously, initiate 
successive draws when the applicable thermostat acts to reduce the 
electrical input to the element located vertically highest in the 
storage tank. For heat pump waters heaters that do not use 
supplemental resistive heating, initiate successive draws 
immediately after the electrical input to the compressor is reduced 
by the action of the water heater's thermostat. For heat pump waters 
heaters that use supplemental resistive heating, initiate successive 
draws immediately after the electrical input to the compressor or 
the uppermost resistive element is reduced by the action of the 
applicable water heater thermostat. This draw initiation criterion 
for heat pump water heaters that use supplemental resistive heating, 
however, shall only apply when the water located above the 
thermostat at cut-out is heated to 135 deg.F5 deg.F 
(57.2 deg.C2.8 deg.C).
    5.1.4.3  Test Sequence. Establish normal water heater operation. 
If the water heater is not presently operating, initiate a draw. The 
draw may be terminated anytime after cut-in occurs. After cut-out 
occurs (i.e., all thermostats are satisfied), monitor the internal 
storage tank temperature sensors described in section 4.5 every 
minute.
    Initiate a draw after a maximum mean tank temperature has been 
observed following cut-out. Record the time when the draw is initiated 
and designate it as an elapsed time of zero (* = 0). (The 
superscript * is used to denote variables pertaining to the first-hour 
rating test.) Record the outlet water temperature beginning 15 seconds 
after the draw is initiated and at 5-second intervals thereafter until 
the draw is terminated. Determine the maximum outlet temperature that 
occurs during this first draw and record it as T*max, 1. For 
the duration of this first draw and all successive draws, in addition, 
monitor the inlet temperature to the water heater to ensure that the 
required 58 deg.F2 deg.F (14.4 deg.C1.1 deg.C) 
test condition is met. Terminate the hot water draw when the outlet 
temperature decreases to T*max,1-25 deg.F 
(T*max,1-13.9 deg.C). Record this temperature as 
T*min,1. Following draw termination, determine the average 
outlet water temperature and the mass or volume removed during this 
first draw and record them as T*del,1 and M*1 or 
V*1, respectively.
    Initiate a second and, if applicable, successive draw each time the 
applicable draw initiation criteria described in section 5.1.4.2 are 
satisfied. As required for the first draw, record the outlet water 
temperature 15 seconds after initiating each draw and at 5-second 
intervals thereafter until the draw is terminated. Determine the 
maximum outlet temperature that occurs during each draw and record it 
as T*max, i, where the subscript i refers to the draw 
number. Terminate each hot water draw when the outlet temperature 
decreases to T*max, i-25 deg.F 
(T*max, i-13.9 deg.C). Record this temperature as 
T*min, i. Calculate and record the average outlet 
temperature and the mass or volume removed during each draw 
(T*del, i and M*i or V*i, 
respectively). Continue this sequence of draw and recovery until one 
hour has elapsed, then shut off the electrical power and/or fuel 
supplied to the water heater.
    If a draw is occurring at an elapsed time of one hour, continue 
this draw until the outlet temperature decreases to 
T*max, n-25 deg.F (T*max, n -13.9 deg.C), at 
which time the draw shall be immediately terminated. (The subscript n 
shall be used to denote quantities associated with the final draw.) If 
a draw is not occurring at an elapsed time of one hour, a final draw 
shall be imposed at one hour. This draw shall be immediately terminated 
when the outlet temperature first indicates a value less than or equal 
to the cut-off temperature used for the previous draw 
(T*min, n-1). For cases where the outlet temperature is 
close to T*min, n-1, the final draw shall proceed for a 
minimum of 30 seconds. If an outlet temperature greater than 
T*min, n-1 is not measured within 30 seconds, the draw shall 
be immediately terminated and zero additional credit shall be given 
towards first-hour rating (i.e., M*n = 0 or V*n = 
0). After the final draw is terminated, calculate and record the 
average outlet temperature and the mass or volume removed during the 
draw (T*del, n and M*n or V*n, 
respectively).
    5.1.5  24-Hour Simulated Use Test. During the simulated use 
test, a total of 64.3 1.0 gallons (2433.8 
liters) shall be removed. This value is referred to as the daily hot 
water usage in the following text.
    With the water heater turned off, fill the water heater with 
supply water and apply pressure as described in section 2.5. Turn on 
the water heater and associated heat pump unit, if present. After 
the cut-out occurs, the water heater may be operated for up to three 
cycles of drawing until cut-in, and then operating until cut-out, 
prior to the start of the test.
    At this time, record the mean tank temperature (To), 
and the electrical and/or fuel measurement readings, as appropriate. 
Begin the 24-hour simulated use test by withdrawing a volume from 
the water heater that equals one-sixth of the daily hot water usage. 
Record the time when this first draw is initiated and assign it as 
the test elapsed time () of zero (0). Record the average 
storage tank and ambient temperature every 15 minutes throughout the 
24-hour simulated use test unless a recovery or a draw is occurring. 
At elapsed time intervals of one, two, three, four, and five hours 
from  = 0, initiate additional draws, removing an amount of 
water equivalent to one-sixth of the daily hot water usage with the 
maximum allowable deviation for any single draw being  
0.5 gallons (1.9 liters). The quantity of water withdrawn during the 
sixth draw shall be increased or decreased as necessary such that 
the total volume of water withdrawn equals 64.3 gallons  
1.0 gallon (243.4 liters  3.8 liters).
    All draws during the simulated use test shall be made at flow 
rates of 3.0 gallons  0.25 gallons per minute (11.4 
liters  0.95 liters per minute). Measurements of the 
inlet and outlet temperatures shall be made 15 seconds after the 
draw is initiated and at every subsequent 5-second interval 
throughout the duration of each draw. The arithmetic mean of the hot 
water discharge temperature and the cold water inlet temperature 
shall be determined for each draw (Tdel, i and 
Tin, i). Determine and record the net mass or volume 
removed (Mi or Vi ), as appropriate, after 
each draw.
    At the end of the recovery period following the first draw, 
record the maximum mean tank temperature observed after cut-out, 
Tmax, 1, and the energy consumed by an electric 
resistance, gas or oil-fired water heater, Qr. For heat 
pump water heaters, the total electrical energy consumed during the 
first recovery by the heat pump (including compressor, fan, 
controls, pump, etc.) and, if applicable, by the resistive 
element(s) shall be recorded as Qr.
    At the end of the recovery period that follows the sixth draw, 
determine and record the total electrical energy and/or fossil fuel 
consumed since the beginning of the test, Qsu. In 
preparation for determining the energy consumed during standby, 
record the reading given on the electrical energy (watt-hour) meter, 
the gas meter, and/or the scale used to determine oil consumption, 
as appropriate. Record the maximum value of the mean tank 
temperature after cut-out as Tsu. Except as noted below, 
allow the water heater to remain in the standby mode until 24 hours 
have elapsed from the start of the test (i.e., since = 0). Prevent 
the water heater from beginning a recovery cycle during the last 
hour of the test by turning off the electric power to the electrical 
heating elements and heat pump, if present, or by turning down the 
fuel supply to the main burner at an elapsed time of 23 hours. If a 
recovery is taking place at an elapsed time of 23 hours, wait until 
the recovery is complete before reducing the electrical and/or fuel 
supply to the water heater. At 24 hours, record the mean tank 
temperature, T24, and the electric and/or fuel instrument 
readings. Determine the total fossil fuel or electrical energy 
consumption, as appropriate, for the entire 24-hour simulated use 
test, Q. Record the time interval between the time at which the 
maximum mean tank temperature is observed after the sixth draw and 
the end of the 24-hour test as stby, 1. Record the time 
during which water is not being withdrawn from the water heater 
during the entire 24-hour period as stby, 2.
    5.2  Instantaneous Gas and Electric Water Heaters
    5.2.1  Setting the Outlet Discharge Temperature. Initiate normal 
operation of the water heater at the full input rating for electric 
instantaneous water heaters and at

[[Page 26013]]

the maximum firing rate specified by the manufacturer for gas 
instantaneous water heaters. Monitor the discharge water temperature 
and set to a value of 135 deg.F  5 deg.F (57.2 deg.C 
 2.8 deg.C) in accordance with the manufacturer's 
instructions. If the water heater is not capable of providing this 
discharge temperature when the flow rate is 3.0 gallons  
0.25 gallons per minute (11.4 liters  0.95 liters per 
minute), then adjust the flow rate as necessary to achieve the 
specified discharge water temperature. Record the corresponding flow 
rate as Vmax.
    5.2.2  Additional Requirements for Variable Input Instantaneous 
Gas Water Heaters. If the instantaneous water heater incorporates a 
controller that permits operation at a reduced input rate, adjust 
the flow rate as necessary to achieve a discharge water temperature 
of 135 deg.F  5 deg.F (57.2 deg.C  
2.8 deg.C) while maintaining the minimum input rate. Record the 
corresponding flow rate as Vmin. If an outlet temperature 
of 135 deg.F  5 deg.F (57.2 deg.C  
2.8 deg.C) cannot be achieved at the minimum flow rate permitted by 
the instantaneous water heater, record the flow rate as 
Vmin and the corresponding outlet temperature as 
Tmin.
    5.2.3  Maximum GPM Rating Test for Instantaneous Water Heaters. 
Establish normal water heater operation at the full input rate for 
electric instantaneous water heaters and at the maximum firing rate 
for gas instantaneous water heaters with the discharge water 
temperature set in accordance with Section 5.2.1. During the 10-
minute test, either collect the withdrawn water for later 
measurement of the total mass removed, or alternatively, use a water 
meter to directly measure the water volume removed.
    After recording the scale or water meter reading, initiate water 
flow throughout the water heater, record the inlet and outlet water 
temperatures beginning 15 seconds after the start of the test and at 
subsequent 5-second intervals throughout the duration of the test. 
At the end of 10 minutes, turn off the water. Determine the mass of 
water collected, M10m, in pounds (kilograms), or the 
volume of water, V10m, in gallons (liters).
    5.2.4 24-hour Simulated Use Test for Gas Instantaneous Water 
Heaters.
    5.2.4.1  Fixed Input Instantaneous Water Heaters. Establish 
normal operation with the discharge water temperature and flow rate 
set to values of 135 deg.F  5 deg.F (57.2 deg.C 
 2.8 deg.C) and Vmax per Section 5.2.1, 
respectively. With no draw occurring, record the reading given by 
the gas meter and/or the electrical energy meter as appropriate. 
Begin the 24-hour simulated use test by drawing an amount of water 
out of the water heater equivalent to one-sixth of the daily hot 
water usage. Record the time when this first draw is initiated and 
designate it as an elapsed time, , of 0. At elapsed time 
intervals of one, two, three, four, and five hours from  = 
0, initiate additional draws, removing an amount of water equivalent 
to one-sixth of the daily hot water usage, with the maximum 
allowable deviation for any single draw being  0.5 
gallons (1.9 liters). The quantity of water drawn during the sixth 
draw shall be increased or decreased as necessary such that the 
total volume of water withdrawn equals 64.3 gallons  1.0 
gallons (243.4 liters  3.8 liters).
    Measurements of the inlet and outlet water temperatures shall be 
made 15 seconds after the draw is initiated and at every 5-second 
interval thereafter throughout the duration of the draw. The 
arithmetic mean of the hot water discharge temperature and the cold 
water inlet temperature shall be determined for each draw. Record 
the scale used to measure the mass of the withdrawn water or the 
water meter reading, as appropriate, after each draw. At the end of 
the recovery period following the first draw, determine and record 
the fossil fuel or electrical energy consumed, Qr. 
Following the sixth draw and subsequent recovery, allow the water 
heater to remain in the standby mode until exactly 24 hours have 
elapsed since the start of the test (i.e., since  = 0). At 
24 hours, record the reading given by the gas meter and/or the 
electrical energy meter as appropriate. Determine the fossil fuel or 
electrical energy consumed during the entire 24-hour simulated use 
test and designate the quantity as Q.
    5.2.4.2  Variable Input Instantaneous Water Heaters. If the 
instantaneous water heater incorporates a controller that permits 
continuous operation at a reduced input rate, the first three draws 
shall be conducted using the maximum flow rate, Vmax, 
while removing an amount of water equivalent to one-sixth of the 
daily hot water usage, with the maximum allowable deviation for any 
one of the three draws being  0.5 gallons (1.9 liters). 
The second three draws shall be conducted at Vmin. If an 
outlet temperature of 135 deg.F  5 deg.F (57.2 deg.C 
 2.8 deg.C) could not be achieved at the minimum flow 
rate permitted by the instantaneous water heater, the last three 
draws should be lengthened such that the volume removed is:
[GRAPHIC] [TIFF OMITTED] TR11MY98.001

or
[GRAPHIC] [TIFF OMITTED] TR11MY98.002

where Tmin is the outlet water temperature at the flow 
rate Vmin as determined in Section 5.2.1, and where the 
maximum allowable variation for any one of the three draws is 
 0.5 gallons (1.9 liters). The quantity of water 
withdrawn during the sixth draw shall be increased or decreased as 
necessary such that the total volume of water withdrawn equals 
(32.15 + 31V4,5,6)  1.0 
gallons
((121.7 + 3V.4,5,6)  3.8 
liters).
    Measurements of the inlet and outlet water temperatures shall be 
made 5 seconds after a draw is initiated and at every 5-second 
interval thereafter throughout the duration of the draw. Determine 
the arithmetic mean of the hot water discharge temperature and the 
cold water inlet temperature for each draw. Record the scale used to 
measure the mass of the withdrawn water or the water meter reading, 
as appropriate, after each draw. At the end of the recovery period 
following the first draw, determine and record the fossil fuel or 
electrical energy consumed, Qr, max. Likewise, record the 
reading of the meter used to measure fossil fuel or electrical 
energy consumption prior to the fourth draw and at the end of the 
recovery period following the fourth draw, and designate the 
difference as Qr,min. Following the sixth draw and 
subsequent recovery, allow the water heater to remain in the standby 
mode until exactly 24 hours have elapsed since the start of the test 
(i.e., since =0). At 24 hours, record the reading given by 
the gas meter and/or the electrical energy meter, as appropriate. 
Determine the fossil fuel or electrical energy consumed during the 
entire 24-hour simulated use test and designate the quantity as Q.

6. Computations

    6.1  Storage Tank and Heat Pump Water Heaters.
    6.1.1  Storage Tank Capacity. The storage tank capacity is 
computed using the following:
[GRAPHIC] [TIFF OMITTED] TR11MY98.003

Where:

Vst = the storage capacity of the water heater, gal (L).
Wf = the weight of the storage tank when completely 
filled with water, lb (kg).
Wt = the (tare) weight of the storage tank when 
completely empty, lb (kg).
 = the density of water used to fill the tank measured at 
the temperature of the water, lb/gal (kg/L).

    6.1.2.  First-Hour Rating Computation. For the case in which the 
final draw is initiated at or prior to an elapsed time of one hour, 
the first-hour rating shall be computed using,

[GRAPHIC] [TIFF OMITTED] TR11MY98.004

Where:

n = the number of draws that are completed during the first-hour 
rating test.
V*i = the volume of water removed during the ith draw of 
the first-hour rating test, gal (L)
or, if the mass of water is being measured,
[GRAPHIC] [TIFF OMITTED] TR11MY98.005

Where:

M*i = the mass of water removed during the ith draw of 
the first-hour rating test, lb (kg).
 = the water density corresponding to the average outlet 
temperature measured during the ith draw, (T*del, I), lb/
gal (kg/L).

    For the case in which a draw is not in progress at the elapsed 
time of one hour and a final draw is imposed at the elapsed time of 
one hour, the first-hour rating shall be calculated using

[[Page 26014]]

[GRAPHIC] [TIFF OMITTED] TR11MY98.006


where n and V*i are the same quantities as defined above, 
and

V*n = the volume of water drawn during the nth (final) 
draw of the first-hour rating test, gal (L)
T*del,n-1 = the average water outlet temperature measured 
during the (n-1)th draw of the first-hour rating test,  deg.F 
( deg.C).
T*del,n = the average water outlet temperature measured 
during the nth (final) draw of the first-hour rating test,  deg.F 
( deg.C).
T*min,n-1 = the minimum water outlet temperature measured 
during the (n-1)th draw of the first-hour rating test,  deg.F 
( deg.C).

    6.1.3  Recovery Efficiency. The recovery efficiency for gas, 
oil, and heat pump storage-type water heaters is computed as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.007

Where:

M1 = total mass removed during the first draw of the 24-
hour simulated use test, lb (kg), or, if the volume of water is 
being measured,
M1 = V11

Where:

V1 = total volume removed during the first draw of the 
24-hour simulated use test, gal (L).
1 = density of the water at the water 
temperature measured at the point where the flow volume is measured, 
lb/gal (kg/L).
Cp1 = specific heat of the withdrawn water, 
(Tdel,1 + Tin,1) / 2, Btu/lb deg.F (kJ/
kg deg.C).
Tdel,1 = average water outlet temperature measured during 
the first draw of the 24-hour simulated use test,  deg.F ( deg.C).
Tin,1 = average water inlet temperature measured during 
the first draw of the 24-hour simulated use test,  deg.F ( deg.C).
Vst = as defined in section 6.1.1.
2 = density of stored hot water, 
(Tmax,1 + To)/2, lb/gal (kg/L).
Cp2 = specific heat of stored hot water evaluated at 
(Tmax,1 + To) / 2, Btu/lb deg.F (kJ/
kg+ deg.C).
Tmax,1 = maximum mean tank temperature recorded after 
cut-out following the first draw of the 24-hour simulated use test, 
deg.F ( deg.C).
To = maximum mean tank temperature recorded prior to the 
first draw of the 24-hour simulated use test,  deg.F ( deg.C).
Qr = the total energy used by the water heater between 
cut-out prior to the first draw and cut-out following the first 
draw, including auxiliary energy such as pilot lights, pumps, fans, 
etc., Btu (kJ). (Electrical auxiliary energy shall be converted to 
thermal energy using the following conversion: 1 kWh = 3,412 Btu.)

    The recovery efficiency for electric water heaters with immersed 
heating elements is assumed to be 98%.
    6.1.4  Hourly Standby Losses. The hourly standby energy losses 
are computed as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.008

Where:

    Qhr = the hourly standby energy losses of the water 
heater, Btu/h (kJ/h).
Qstby = the total energy consumed by the water heater 
between the time at which the maximum mean tank temperature is 
observed after the sixth draw and the end of the 24-hour test 
period, Btu (kJ).
Vst = as defined in section 6.1.1.
 = density of stored hot water, (T24 + 
Tsu) / 2, lb/gal (kg/L).
Cp = specific heat of the stored water, (T24 + 
Tsu) / 2, Btu/lb deg.F (kJ/kg deg.C).
T24 = the mean tank temperature at the end of the 24-hour 
simulated use test,  deg.F ( deg.C).
Tsu = the maximum mean tank temperature observed after 
the sixth draw,  deg.F ( deg.C).
r = as defined in section 6.1.3.
stby, 1 = elapsed time between the time at which 
the maximum mean tank temperature is observed after the sixth draw 
and the end of the 24-hour simulated use test, h.

    The standby heat loss coefficient for the tank is computed as:
    [GRAPHIC] [TIFF OMITTED] TR11MY98.009
    
Where:

UA = standby heat loss coefficient of the storage tank, Btu/
h deg.F (kJ/h deg.C).
Qhr = as defined in this section.
Tt, stby,1= overall average storage tank temperature 
between the time when the maximum mean tank temperature is observed 
after the sixth draw and the end of the 24-hour simulated use test, 
deg.F ( deg.C).
Ta, stby,1= overall average ambient temperature between 
the time when the maximum mean tank temperature is observed after 
the sixth draw and the end of the 24-hour simulated use test,  deg.F 
( deg.C).

    6.1.5  Daily Water Heating Energy Consumption. The daily water 
heating energy consumption, Qd, is computed as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.010

Where:

Q = total energy used by the water heater during the 24-hour 
simulated use test including auxiliary energy such as pilot lights, 
pumps, fans, etc., Btu (kJ). (Electrical auxiliary energy shall be 
converted to thermal energy using the following conversion: 1 kWh = 
3,412 Btu.)
Vst = as defined in section 6.1.1.
= density of the stored hot water, (T24 + 
To) / 2, lb/gal (kg/L).
Cp = specific heat of the stored water, (T24 + 
To) / 2, Btu/lb deg.F (kJ/kg deg.C).
T24 = mean tank temperature at the end of the 24-hour 
simulated use test,  deg.F ( deg.C).
To = mean tank temperature at the beginning of the 24-
hour simulated use test, recorded one minute before the first draw 
is initiated,  deg.F ( deg.C).
r = as defined in section 6.1.3.

    6.1.6  Adjusted Daily Water Heating Energy Consumption. The 
adjusted daily water heating energy consumption, Qda, 
takes into account that the temperature difference between the 
storage tank and surrounding ambient air may not be the nominal 
value of 67.5 deg.F (135 deg.F-67.5 deg.F) or 37.5 deg.C 
(57.2 deg.C-19.7 deg.C) due to the 10 deg.F (5.6 deg.C) allowable 
variation in storage tank temperature, 135 deg.F  
5 deg.F (57.2 deg.C  2.8 deg.C), and the 5 deg.F 
(2.8 deg.C) allowable variation in surrounding ambient temperature 
65  deg.F (18.3 deg.C) to 70 deg.F (21.1 deg.C). The adjusted daily 
water heating energy consumption is computed as:

Qda = QD - [(Tstby, 2 - 
Ta, stby,2) - (135 deg.F - 67.5 deg.F)] 
UAstby, 2
or Qda = QD - [(Tstby, 2 
- Ta, stby, 2) - (57.2 deg.C - 19.7 deg.C)] 
UAstby, 2
Where:

Qda = the adjusted daily water heating energy 
consumption, Btu (kJ).
Qd = as defined in section 6.1.5.
Tstby, 2 = the mean tank temperature during the total 
standby portion, stby, 2, of the 24-hour test, 
deg.F ( deg.C).
Ta, stby, 2 = the average ambient temperature during the 
total standby portion, stby, 2, of the 24-
hour test,  deg.F ( deg.C).
UA = as defined in section 6.1.4.
stby, 2 = the number of hours during the 24-hour 
simulated test when water is not being withdrawn from the water 
heater.

    A modification is also needed to take into account that the 
temperature difference between the outlet water temperature and 
supply water temperature may not be equivalent to the nominal value 
of 77 deg.F

[[Page 26015]]

(135 deg.F-58 deg.F) or 42.8 deg.C (57.2 deg.C-14.4 deg.C). The 
following equations adjust the experimental data to a nominal 
77 deg.F (42.8 deg.C) temperature rise.
    The energy used to heat water, Btu/day (kJ/day), may be computed 
as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.011

Where:

Mi = the mass withdrawn for the ith draw (i = 1 to 6), lb 
(kg).
Cpi = the specific heat of the water of the ith draw, 
Btu/lb deg.F (kJ/kg deg.C).
Tdel, i = the average water outlet temperature measured 
during the ith draw (i=1 to 6),  deg.F ( deg.C).
Tin, i = the average water inlet temperature measured 
during the ith draw (i=1 to 6),  deg.F ( deg.C).
r = as defined in section 6.1.3.
    The energy required to heat the same quantity of water over a 
77 deg.F (42.8 deg.C) temperature rise, Btu/day (kJ/day), is:
[GRAPHIC] [TIFF OMITTED] TR11MY98.012

    The difference between these two values is:

QHWD = QHW, 77+-F -QHW
or QHWD = QHW,42.8+-F -QHW
which must be added to the adjusted daily water heating energy 
consumption value. Thus, the daily energy consumption value which 
takes into account that the temperature difference between the 
storage tank and ambient temperature may not be 67.5 deg.F 
(37.5 deg.C) and that the temperature rise across the storage tank 
may not be 77 deg.F (42.8 deg.C) is:

Qdm = Qda + QHWD

    6.1.7  Energy Factor. The energy factor, Ef, is computed as:
    [GRAPHIC] [TIFF OMITTED] TR11MY98.013
    
or
[GRAPHIC] [TIFF OMITTED] TR11MY98.014

Where:

Qdm = the modified daily water heating energy consumption 
as computed in accordance with section 6.1.6, Btu (kJ).
Mi = the mass withdrawn for the ith draw (i = 1 to 6), lb 
(kg).
Cpi = the specific heat of the water of the ith draw, 
Btu/lb  deg.F (kJ/kg  deg.C).

    6.1.8  Annual Energy Consumption. The annual energy consumption 
for storage-type and heat pump water heaters is computed as:

Eannual  = 365  x  Qdm

Where:

Qdm = the modified daily water heating energy consumption 
as computed in accordance with section 6.1.6, Btu (kJ).
365 = the number of days in a year.

    6.2  Instantaneous Water Heaters.
    6.2.1  Maximum GPM (L/min) Rating Computation. Compute the 
maximum gpm (L/min) rating as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.015

which may be expressed as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.016

Where:

M10m = the mass of water collected during the 10-minute 
test, lb (kg).
Tdel = the average delivery temperature,  deg.F ( deg.C).
Tin = the average inlet temperature,  deg.F ( deg.C).
 = the density of water at the average delivery 
temperature, lb/gal (kg/L).

    If a water meter is used the maximum gpm (L/min) rating is 
computed as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.017

Where:

V10m = the volume of water measured during the 10-minute 
test, gal (L).
Tdel = as defined in this section.
Tin = as defined in this section.

    6.2.2  Recovery Efficiency
    6.2.2.1  Fixed Input Instantaneous Water Heaters. The recovery 
efficiency is computed as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.018

Where:

M1 = total mass removed during the first draw of the 24-
hour simulated use test, lb (kg), or, if the volume of water is 
being measured,
M1 = V1 . 

Where:

V1 = total volume removed during the first draw of the 
24-hour simulated use test, gal (L).
= density of the water at the water temperature measured at 
the point where the flow volume is measured, lb/gal (kg/L).
Cp1 = specific heat of the withdrawn water, 
(Tdel,1 + Tin,1) / 2, Btu/lb  deg.F (kJ/kg 
deg.C).
Tdel, 1 = average water outlet temperature measured 
during the first draw of the 24-hour simulated use test,  deg.F 
( deg.C).
Tin, 1 = average water inlet temperature measured during 
the first draw of the 24-hour simulated use test,  deg.F ( deg.C).
Qr = the total energy used by the water heater between 
cut-out prior to the first draw and cut-out following the first 
draw, including auxiliary energy such as pilot lights, pumps, fans, 
etc., Btu (kJ). (Electrical auxiliary energy shall be converted to 
thermal energy using the following conversion: 1 kWh = 3,412 Btu.)
    6.2.2.2  Variable Input Instantaneous Water Heaters. For 
instantaneous water heaters that have a variable firing rate, two 
recovery efficiency values are computed, one at the maximum input 
rate and one at the minimum input rate. The recovery efficiency used 
in subsequent computations is taken as the average of these two 
values. The maximum recovery efficiency is computed as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.019

Where:

M1 = as defined in section 6.2.2.1.
Cp1 = as defined in section 6.2.2.1.
Tdel, 1 = as defined in section 6.2.2.1.
Tin, 1 = as defined in section 6.2.2.1.
Qr, max = the total energy used by the water heater 
between burner cut-out prior to the first draw and burner cut-out 
following the first draw, including auxiliary energy such as pilot 
lights, Btu (kJ).

    The minimum recovery efficiency is computed as:
    [GRAPHIC] [TIFF OMITTED] TR11MY98.020
    
Where:

M4 = the mass withdrawn during the fourth draw, lb (kg), 
or, if the volume of water is being measured,
M4 = V4

Where:

V4 = total volume removed during the first draw of the 
24-hour simulated use test, gal (L).
 = as defined in 6.2.2.1
Cp4 = the specific heat of water, Btu/lb deg.F (kJ/kg 
deg.C).
Tdel, 4 = the average delivery temperature for the fourth 
draw,  deg.F ( deg.C).
Tin, 4 = the average inlet temperature for the fourth 
draw,  deg.F ( deg.C).
Qr, min = the total energy consumed between the beginning 
of the fourth draw and burner cut-out following the fourth draw, 
including auxiliary energy such as pilot lights, Btu (kJ).

    The recovery efficiency is computed as:

[[Page 26016]]

[GRAPHIC] [TIFF OMITTED] TR11MY98.021


      
Where:

r,max = as calculated above.
r,min = as calculated above.

    6.2.3  Daily Water Heating Energy Consumption. The daily water 
heating energy consumption, Qd, is computed as:

Qd = Q

Where:
Q = the energy used by the instantaneous water heater during the 24-
hr simulated use test.

    A modification is needed to take into account that the 
temperature difference between the outlet water temperature and 
supply water temperature may not be equivalent to the nominal value 
of 77 deg.F (135 deg.F-58 deg.F) or 42.8 deg.C 
(57.2 deg.C-14.4 deg.C). The following equations adjust the 
experimental data to a nominal 77 deg.F (42.8 deg.C) temperature 
rise.
    The energy used to heat water may be computed as:
    [GRAPHIC] [TIFF OMITTED] TR11MY98.022
    
Where:

Mi = the mass withdrawn during the ith draw, lb (kg).
Cpi = the specific heat of water of the ith draw, Btu/
lb deg.F (kJ/kg ( deg.C).
Tdel,i = the average delivery temperature of the ith 
draw,  deg.F ( deg.C).
Tin,i = the average inlet temperature of the ith draw, 
deg.F ( deg.C).
r = as calculated in section 6.2.2.2.

    The energy required to heat the same quantity of water over a 
77 deg.F (42.8 deg.C) temperature rise is:
[GRAPHIC] [TIFF OMITTED] TR11MY98.023

Where:

Mi = the mass withdrawn during the ith draw, lb (kg).
Cpi = the specific heat of water of the ith draw, Btu/
lb deg.F (kJ/kg ( deg.C).
r = as calculated above.

    The difference between these two values is:

QHWD = QHW, 77 deg.F - QHW
or QHWD = QHW, 42.8 deg.C - 
QHW

which much be added to the daily water heating energy 
consumption value. Thus, the daily energy consumption value which 
takes into account that the temperature rise across the storage tank 
may not be 77 deg.F (42.8 deg.C) is:
Qdm = Qd + QHWD

    6.2.4  Energy Factor. The energy factor, Ef, is 
computed as:
[GRAPHIC] [TIFF OMITTED] TR11MY98.024

Where:

Qdm = the daily water heating energy consumption as 
computed in accordance with section 6.2.3, Btu (kJ).
Mi = the mass associated with the ith draw, lb (kg).
Cpi = the specific heat of water computed at a 
temperature of (58 deg.F + 135 deg.F) / 2, Btu/lb  deg.F 
[(14.4 deg.C + 57.2 deg.C) / 2, kJ/kg  deg.C].

    6.2.5  Annual Energy Consumption. The annual energy consumption 
for instantaneous type water heaters is computed as:

Eannual = 365  x  Qdm

Where:

Qdm = the modified daily energy consumption, Btu/day (kJ/
day).
365 = the number of days in a year.

7. Ratings for Untested Models

    In order to relieve the test burden on manufacturers who offer 
water heaters which differ only in fuel type or power input, ratings 
for untested models may be established in accordance with the 
following procedures. In lieu of the following procedures a 
manufacturer may elect to test the unit for which a rating is 
sought.
    7.1  Gas Water Heaters. Ratings obtained for gas water heaters 
using natural gas can be used for an identical water heater which 
utilizes propane gas if the input ratings are within  
10%.
    7.2  Electric Water Heaters
    7.2.1  First-Hour Rating. If an electric storage-type water 
heater is available with more than one input rating, the 
manufacturer shall designate the standard input rating, and the 
water heater need only be tested with heating elements at the 
designated standard input ratings. The first-hour ratings for units 
having power input rating less than the designated standard input 
rating shall be assigned a first-hour rating equivalent to the first 
draw of the first-hour rating for the electric water heater with the 
standard input rating. For units having power inputs greater than 
the designated standard input rating, the first-hour rating shall be 
equivalent to that measured for the water heater with the standard 
input rating.
    7.2.2  Energy Factor. The energy factor for identical electric 
storage-type water heaters, with the exception of heating element 
wattage, may use the energy factor obtained during testing of the 
water heater with the designated standard input rating.

[FR Doc. 98-12296 Filed 5-8-98; 8:45 am]
BILLING CODE 6450-01-P`