federal register

25995

Monday

May 11, 1998

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
25996 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

1Part 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.

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, terry.logee@hq.doe.gov.

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, eugene.margolis@hq.doe.gov.

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 FossilFueled 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.

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 firsthour 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 oilfired 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°F (57.2°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
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 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 oilfired 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 wholehouse 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 cooldown 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°F (42.8°C) temperature rise (from

58°F to 135°F [14.4°C to 57.2°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 cooldown 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
25998 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

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 oilfired 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 firsthour 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°F (42.8°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°F (27.8°C) temperature

rise if a single rating value is used, and

at both a 50°F and 77°F temperature rise

if two rating values are used. EPRI

stated that it prefers a rating at both a

50°F and 77°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°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°F, not 50°F as

suggested by other commenters.

(GAMA, No. 35 at 2.) GAMA stated it

selected a temperature rise of 77°F

because hot water also will be used for

machine-related applications

(dishwashers and clothes washers) that

require a 135°F (57.2°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°F

and 77°F rise. Virginia Power stated that

both temperature rises are used in

applications (human-contact at 110°F

[43.3°C] and machine use at 135°F

[57.2°C]. Virginia further stated that

DOE’s statement in the October 1997

reopening notice that a 77°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°F and 77°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°F would not provide

consumers with information on whether

the heater is capable of delivering hot

water at a 77°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°F [42.8°C] or 50°F [27.8°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°F (57.2–

60°C) range, information on the amount

of flow at a 77°F rise is needed. Also,

a rating value based on a nominal

temperature rise of 50°F would not

provide consumers with information on

whether the heater is capable of

delivering hot water at 135°F. Therefore,

DOE believes that the maximum flow

rate at the rated energy input rate and

at a temperature rise of 77°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 firsthour rating. The Department is therefore

creating a new rating for instantaneous

gas and electric water heaters using a

‘‘maximum gpm draw rate at 77°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 gasfired 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°F because there is no practical

domestic use for water at 135°F. (CEC,

February 1997 Transcript at Appendix

H at 4 and No. 63 at 3.) Additionally,

CEC claimed the 135°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°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°F because there

are many places like Miami and Texas

with high ground water temperatures for
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 25999

most, if not all, of the year. EPRI

supported a 50°F temperature rise

because that is representative of typical

human usage and a rise of 77°F because

that is typical of machine usage. A.O.

Smith favored a single rating at a 77°F

temperature rise because it is simpler

and allows comparisons with storagetype 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°F inlet (Title

10 CFR, Part 430, Subpart B, Appendix

E, Section 2.3) with a 77°F rise to

address (1) machine-use applications

that require a 135°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°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°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 gasfired 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°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°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
26000 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

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 smallervolume 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 floormounted 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 standby 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 standby loss requirement in ASHRAE 90A–

1980 was 43W. GAMA asserted that

because the ASHRAE loss was based on

an 80°F temperature difference, the DOE

maximum loss rate should be 36.3W,

based on the 67.5°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 standby 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
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 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 airto-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 backup 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,
26002 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

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 heatpump-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°F ± 5°F (57.2°C ±

2.8°C) and all the thermostats are

satisfied. The first draw is terminated

when the outlet water temperature

decreases by 25°F (13.9°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°F

(13.9°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°F (13.9°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 nextto-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
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 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°F (43.3°C) and (2) the maximum

useful reheat volume (water is heated to

110°F [43.3°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 21⁄2 year EPRI field study

at 14 metered sites with electric storagetype 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°F (57.2°C) instead of 110°F (43.3°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 firsthour 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
26004 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

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 firsthour 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 gasfired 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 firsthour 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 firsthour 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°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°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°F or the thermostat to cut out before

turning on the hot water faucet, the onehour 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 onehour mark, two similar tanks, one at

111°F and the other at 109°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°F is drawn, the
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 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°F and

the average outlet water temperature

during a regular—not the imposed—

draw is assumed to be 130°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 onehour 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 onehour 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 demandside 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°F (heated up from the 58°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 underthe-counter water heaters from countertop 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 floormounted 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
26006 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

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°F ± 5°F (57.2°C ± 2.8°C).

DOE did not propose to revise this

setting in the 1995 proposed

rulemaking. AGA suggested that the

thermostat setting be lowered to 120°F

± 5°F (48.9°C ± 2.8°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°F

(48.9°C). The reasons cited included: (1)

The current setting of 135°F (57.2°C)

does not reflect how consumers actually

operate their water heaters; (2) most

energy-related organizations advocate a

setting of 120° ±F (48.9°C) when

promoting energy efficiency and safety;

(3) scalding by hot water at 135°F

(57.2°C) is a major concern in some

areas; and (4) certain local codes restrict

the thermostat setting to be no higher

than 120°F (48.9°C). EEI stated that for

several years many customers have been

told to set their thermostats at 120°F

(48.9°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°F ± 5°F (57.2°C ± 2.8°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°F (48.9°C) could pose

a potential health risk (e.g., legionella)

to consumers; (2) a setting at 135°F

(57.2°C) is necessary to meet consumers’

expected hot water needs (as with

machine-use for washing clothes); (3) a

setting at 135°F (57.2°C) reflects realistic

household settings; and (4) changing the

thermostat setting from 135°F (57.2°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°F ±

5°F (57.2°C ± 2.8°C) to 120°F ± 5°F

(48.9°C ± 2.8°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 671⁄2°F ± 1°F (19.7°C

± 0.6°C) and for all other water heater

types to be between 65° F (18.3°C) and

70° F (21.1°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°F ±

2°F (14.4°C ± 1.1°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 fossilfueled 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
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 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
26008 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

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°F (82°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°F (42.8°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:

τstby,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; τstby,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°F (82°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°F (82°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°F (82°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°F (82°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
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 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°F (42.8°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°F (42.8°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 cutout (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

τstby, 1

Qsu total fossil fueled and/or electric energy

consumed from the beginning of the first

draw to the thermostat (or burner) cutout 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

T ̄ 0 mean tank temperature at the beginning of

the 24-hr simulated use test

T ̄ 24 mean tank temperature at the end of the

24-hr simulated use test

T ̄ a, stby average ambient air temperature

during standby periods of the 24-hr use

test

T ̄ del for instantaneous water heaters, average

outlet water temperature during a 10-

minute continuous draw interval in the

maximum gpm (L/min) rating test

T ̄ del, i average outlet water temperature during

the ith draw of the 24-hr simulated use

test

T ̄in for instantaneous water heaters, average

inlet water temperature during a 10-

minute continuous draw interval in the

maximum gpm (L/min) rating test

T ̄ in, i average inlet water temperature during

the ith draw of the 24-hr simulated use

test

T ̄ max, 1 maximum measured mean tank

temperature after cut-out following the

first draw of the 24-hr simulated use test

T ̄ stby average storage tank temperature during

the standby period τstby, 2 of the 24-hr use

test

T ̄ su maximum measured mean tank

temperature after cut-out following the

sixth draw of the 24-hr simulated use

test

T ̄ t, stby average storage tank temperature

during the standby period τ stby, 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 firsthour 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°F ± 5°F (57.2°C ± 2.8°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°F ± 5°F

(57.2°C ± 2.8°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 n

r recovery efficiency p density of water

τstby, 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

τstby, 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°F and 70.0°F (18.3°C and

21.1°C) on a continuous basis. For heat pump

water heaters, the dry bulb temperature shall

be maintained at 67.5°F ± 1°F (19.7°C ±

0.6°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°F

± 2°F (14.4°C ± 1.1°C) throughout the test.

2.4 Storage Tank Temperature. The

average temperature of the water within the

storage tank shall be set to 135°F ± 5°F

(57.2°C ± 2.8°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
26010 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

having a heating value of approximately

138,700 Btu per gallon (38,660 kJ per liter).

3. Instrumentation

3.1 Pressure Measurements. Pressuremeasuring instruments shall have an error no

greater than the following values:

Item measured Instrument accuracy Instrument precision

Gas pressure .................................................... ± 0.1 inch of water column (± 0.025 kPa) ........ ± 0.05 inch of water column (± 0.012 kPa).

Atmospheric pressure ....................................... ± 0.1 inch of mercury column (± 0.34 kPa) ...... ± 0.05 inch of mercury column (± 0.17 kPa).

Water pressure ................................................. ± 1.0 pounds per square inch (± 6.9 kPa) ....... ± 0.50 pounds per square inch (± 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°F (± 0.1°C) .............................................................. ± 0.1°F (± 0.06°C)

Air wet bulb temperature .................................................. ± 0.2°F (± 0.1°C) .............................................................. ± 0.1°F (± 0.06°C)

Inlet and outlet water temperatures ................................. ± 0.2°F (± 0.1°C) .............................................................. ± 0.1°F (± 0.06°C)

Storage tank temperatures ............................................... ± 0.5°F (± 0.3°C) .............................................................. ± 0.25°F (± 0.14°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 × 4 inch (5 cm

× 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 × 4 inch

(5 cm × 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 wallmounted 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-thecounter 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
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 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 h•ft2•°F/Btu (0.7 and

1.4 m2•°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°F±5°F (57.2°C±2.8°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°F±5°F

(57.2°C±2.8°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°F±5°F (57.2°C±2.8°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°F±5°F (57.2°C±2.8°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°F±5°F (57.2°C±2.8°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°F±5°F (57.2°C±2.8°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 3.0±0.25 gallons per

minute (11.4±0.95 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
26012 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

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°F±5°F (57.2°C±2.8°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 (τ* = 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°F±2°F

(14.4°C±1.1°C) test condition is met.

Terminate the hot water draw when the

outlet temperature decreases to

T*max,1¥25°F (T*max,1¥13.9°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°F (T*max,

i¥13.9°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°F (T*max, n ¥13.9°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 (243±3.8 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 (T ̄ o), 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 (τ) 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 τ = 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 (T ̄ del, i and T ̄ in, 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, T ̄ max,

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

T ̄ su. 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, T ̄ 24, 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
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 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°F ± 5°F

(57.2°C ± 2.8°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°F ± 5°F (57.2°C ±

2.8°C) while maintaining the minimum input

rate. Record the corresponding flow rate as

Vmin. If an outlet temperature of 135°F ± 5°F

(57.2°C ± 2.8°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°F ± 5°F (57.2°C ± 2.8°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, τ, of 0. At

elapsed time intervals of one, two, three,

four, and five hours from τ = 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 τ = 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°F ± 5°F (57.2°C ± 2.8°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:

V gal F

T F 4 5 6

64 3

6

77

58 , ,

min

. = × °

( ) − °

















or

V L C

T C 4 5 6

243

6

42 8

14 , ,

min

.

.4

= × °

( − ° )

















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 + 3Τ1•V4,5,6) ± 1.0 gallons

((121.7 + 3•V. 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 τ=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:

V

W W

st

f t = ( ) −

ρ

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).

ρ = 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,

F V hr i

i

n

=

=

∑ *

1

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,

V M

i

* i

*

= ρ

Where:

M*i = the mass of water removed during the

ith draw of the first-hour rating test, lb

(kg).

ρ = 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
26014 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

F V V

T T

T T hr i n

del n n

i del n n

n

= + −

−











 −

= − −

−

∑ * * ,

*

min,

*

,

*

min,

*

1

1 1 1

1 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,

°F (°C).

T ̄ *del,n = the average water outlet temperature

measured during the nth (final) draw of

the first-hour rating test, °F (°C).

T ̄ *min,n¥1 = the minimum water outlet

temperature measured during the

(n¥1)th draw of the first-hour rating test,

°F (°C).

6.1.3 Recovery Efficiency. The recovery

efficiency for gas, oil, and heat pump storagetype water heaters is computed as:

η

ρ

r

p del in

r

st p o

r

M C T T

Q

V C T T

Q = ( ) − +

1 1 1 1 2 2 1 , , max, ( ) −

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 ρ1

Where:

V1 = total volume removed during the first

draw of the 24-hour simulated use test,

gal (L).

ρ1 = 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,

(T ̄ del,1 + T ̄ in,1) / 2, Btu/lb°F (kJ/kg°C).

T ̄ del,1 = average water outlet temperature

measured during the first draw of the 24-

hour simulated use test, °F (°C).

T ̄ in,1 = average water inlet temperature

measured during the first draw of the 24-

hour simulated use test, °F (°C).

Vst = as defined in section 6.1.1.

ρ2 = density of stored hot water, (T ̄ max,1 + T ̄ o)/

2, lb/gal (kg/L).

Cp2 = specific heat of stored hot water

evaluated at (T ̄ max,1 + T ̄ o) / 2, Btu/lb°F

(kJ/kg°°C).

T ̄ max,1 = maximum mean tank temperature

recorded after cut-out following the first

draw of the 24-hour simulated use test,

°F (°C).

T ̄ o = maximum mean tank temperature

recorded prior to the first draw of the 24-

hour simulated use test, °F (°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:

Q

Q

V C T T

hr

stby

st p su

r

stby

=

− ρ ( ) −

η

τ

24

1,

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.

ρ = density of stored hot water, (T ̄ 24 + T ̄ su)

/ 2, lb/gal (kg/L).

Cp = specific heat of the stored water, (T ̄ 24 +

T ̄ su) / 2, Btu/lb•°F (kJ/kg•°C).

T ̄ 24 = the mean tank temperature at the end

of the 24-hour simulated use test, °F (°C).

T ̄ su = the maximum mean tank temperature

observed after the sixth draw, °F (°C).

ηr = as defined in section 6.1.3.

τstby, 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:

UA Q

T T

hr

t stby a stby

=

, , , , 1 1 −

Where:

UA = standby heat loss coefficient of the

storage tank, Btu/h•°F (kJ/h•°C).

Qhr = as defined in this section.

T ̄ t, 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, °F

(°C).

T ̄ a, 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, °F (°C).

6.1.5 Daily Water Heating Energy

Consumption. The daily water heating energy

consumption, Qd, is computed as:

Q Q

V C T T

d

st p o

r

= − ρ ( ) −

η

24

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.

ρ= density of the stored hot water, (T ̄ 24 + T ̄ o)

/ 2, lb/gal (kg/L).

Cp = specific heat of the stored water, (T ̄ 24 +

T ̄ o) / 2, Btu/lb•°F (kJ/kg•°C).

T ̄ 24 = mean tank temperature at the end of the

24-hour simulated use test, °F (°C).

T ̄ o = mean tank temperature at the beginning

of the 24-hour simulated use test,

recorded one minute before the first

draw is initiated, °F (°C).

ηr = 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°F (135°F–67.5°F) or 37.5°C (57.2°C–

19.7°C) due to the 10°F (5.6°C) allowable

variation in storage tank temperature, 135°F

± 5°F (57.2°C ± 2.8°C), and the 5°F (2.8°C)

allowable variation in surrounding ambient

temperature 65 °F (18.3°C) to 70°F (21.1°C).

The adjusted daily water heating energy

consumption is computed as:

Qda = QD ¥ [(T ̄ stby, 2 ¥ T ̄ a, stby,2) ¥ (135°F

¥ 67.5°F)] UAτstby, 2

or Qda = QD ¥ [(T ̄ stby, 2 ¥ T ̄ a, stby, 2) ¥ (57.2°C

¥ 19.7°C)] UAτstby, 2

Where:

Qda = the adjusted daily water heating energy

consumption, Btu (kJ).

Qd = as defined in section 6.1.5.

T ̄ stby, 2 = the mean tank temperature during

the total standby portion, τstby, 2, of the

24-hour test, °F (°C).

T ̄ a, stby, 2 = the average ambient temperature

during the total standby portion, τstby, 2,

of the 24-hour test, °F (°C).

UA = as defined in section 6.1.4.

τstby, 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°F
Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations 26015

(135°F–58°F) or 42.8°C (57.2°C–14.4°C). The

following equations adjust the experimental

data to a nominal 77°F (42.8°C) temperature

rise.

The energy used to heat water, Btu/day (kJ/

day), may be computed as:

Q

M C T T

HW

i pi del i in i

i r

= ( ) −

=

∑ , ,

η 1

6

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•°F (kJ/kg•°C).

T ̄ del, i = the average water outlet temperature

measured during the ith draw (i=1 to 6),

°F (°C).

T ̄ in, i = the average water inlet temperature

measured during the ith draw (i=1 to 6),

°F (°C).

ηr = as defined in section 6.1.3.

The energy required to heat the same

quantity of water over a 77°F (42.8°C)

temperature rise, Btu/day (kJ/day), is:

Q

M C F F

or Q

M C C C

HW F

i pi

i r

HW C

i pi

i r

,

, .

. .4

77

1

6

42 8

1

6

135 58

57 2 14

°

=

°

=

= ( ° − ° )

= ( ° − ° )

∑

∑

η

η

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°F (37.5°C) and that the temperature rise

across the storage tank may not be 77°F

(42.8°C) is:

Qdm = Qda + QHWD

6.1.7 Energy Factor. The energy factor, Ef,

is computed as:

E

M C F F

Q f

i pi

i dm

= ( ° − ° )

=

∑ 135 58

1

6

or

E

M C C C

Q f

i pi

i dm

= ( ° − ° )

=

∑ 57 2 14

1

6 . .4

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 °F (kJ/kg °C).

6.1.8 Annual Energy Consumption. The

annual energy consumption for storage-type

and heat pump water heaters is computed as:

Eannual = 365 × 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:

F

M T T

F F

or F

M T T

C C

m del in

m del in

max

max . .4

= ( ) −

( )( ° − ° )

= ( ) −

( )( ° − ° )

10

10

10 135 58

10 57 2 14

ρ

ρ

which may be expressed as:

F

M T T

F

or F

M T T

C

m del in

m del in

max

max .

= ( ) −

( )( ) °

= ( ) −

( )( ) °

10

10

10 77

10 42 8

ρ

ρ

Where:

M10m = the mass of water collected during the

10-minute test, lb (kg).

T ̄ del = the average delivery temperature, °F

(°C).

T ̄ in = the average inlet temperature, °F (°C).

ρ = 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:

F

V T T

F

or F

V T T

C

m del in

m del in

max

max .

= ( ) −

( ) °

= ( ) −

( ) °

10

10

10 77

10 42 8

Where:

V10m = the volume of water measured during

the 10-minute test, gal (L).

T ̄ del = as defined in this section.

T ̄ in = 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:

ηr

p del in

r

M C T T

Q = 1 1 1 1, , ( ) −

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 . ρ

Where:

V1 = total volume removed during the first

draw of the 24-hour simulated use test,

gal (L).

ρ= 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,

(T ̄ del,1 + Tin,1) / 2, Btu/lb °F (kJ/kg °C).

T ̄ del, 1 = average water outlet temperature

measured during the first draw of the 24-

hour simulated use test, °F (°C).

T ̄ in, 1 = average water inlet temperature

measured during the first draw of the 24-

hour simulated use test, °F (°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:

ηr

p del in

r

M C T T

Q , max

, ,

, max

= 1 1 1 1 ( ) −

Where:

M1 = as defined in section 6.2.2.1.

Cp1 = as defined in section 6.2.2.1.

T ̄ del, 1 = as defined in section 6.2.2.1.

T ̄ in, 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:

ηr

p del in

r

M C T T

Q , min

, ,

, min

= 4 4 4 4 ( − )

Where:

M4 = the mass withdrawn during the fourth

draw, lb (kg), or, if the volume of water

is being measured,

M4 = V4 ρ

Where:

V4 = total volume removed during the first

draw of the 24-hour simulated use test,

gal (L).

ρ = as defined in 6.2.2.1

Cp4 = the specific heat of water, Btu/lb°F (kJ/

kg °C).

T ̄ del, 4 = the average delivery temperature for

the fourth draw, °F (°C).

T ̄ in, 4 = the average inlet temperature for the

fourth draw, °F (°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:
26016 Federal Register / Vol. 63, No. 90 / Monday, May 11, 1998 / Rules and Regulations

η

η η

r

r max r = , , min +

2

Where:

ηr,max = as calculated above.

ηr,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°F

(135°F¥58°F) or 42.8°C (57.2°C¥14.4°C).

The following equations adjust the

experimental data to a nominal 77°F (42.8°C)

temperature rise.

The energy used to heat water may be

computed as:

Q

M C T T

HW

i pi del i in i

i r

= ( ) −

=

∑ , ,

η 1

6

Where:

Mi = the mass withdrawn during the ith

draw, lb (kg).

Cpi = the specific heat of water of the ith

draw, Btu/lb°F (kJ/kg (°C).

T ̄ del,i = the average delivery temperature of

the ith draw, °F (°C).

T ̄ in,i = the average inlet temperature of the ith

draw, °F (°C).

ηr = as calculated in section 6.2.2.2.

The energy required to heat the same

quantity of water over a 77°F (42.8°C)

temperature rise is:

Q

M C F F

or Q

M C C C

HW F

i pi

i r

HW C

i pi

i r

,

, .

. .

77

1

6

42 8

1

6

135 58

57 2 14 4

°

=

°

=

= ( ° − ° )

= ( ° − ° )

∑

∑

η

η

Where:

Mi = the mass withdrawn during the ith

draw, lb (kg).

Cpi = the specific heat of water of the ith

draw, Btu/lb°F (kJ/kg (°C).

ηr = as calculated above.

The difference between these two values is:

QHWD = QHW, 77°F ¥ QHW

or QHWD = QHW, 42.8°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°F (42.8°C) is:

Qdm = Qd + QHWD

6.2.4 Energy Factor. The energy factor, Ef,

is computed as:

E

M C F F

Q

or E

M C C C

Q

f

i pi

i dm

f

i pi

i dm

= ( ° − ° )

= ( ° − ° )

=

=

∑

∑

135 58

57 2 14

1

6

1

6 . .4

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°F + 135°F) / 2, Btu/

lb °F [(14.4°C + 57.2°C) / 2, kJ/kg °C].

6.2.5 Annual Energy Consumption. The

annual energy consumption for

instantaneous type water heaters is computed

as:

Eannual = 365 × 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