C-TP-77-002 COMMENT 03

TUESDAY, OCTOBER 1977 

PART m 

II 

ENER Y CONSERV ATI N 

PR GR F R 

C PLI NCES -

Test Procedures for Water Heaters 
C-TP-77-002 COMMENT 03

5-1110 

[ 3128-01] 

Title 10-Energy 

CHAPTER II-FEDERAL ENERGY ADMINISTRATION 

PART 430-ENERGY CONSERVATION 

PROGRAM FOR APPLIANCES 

Test Procedures for Water Heaters 

AGENCY: Federal Energy Administration. 

ACTION: Final rule. 

SUMMARY: This rule prescribes final 

test procedures for water heaters. Appliance test procedures are one element 

of the appliance energy efficiency program required by the Energy Policy and 

Conservation Act. 

EFFECTIVE DATE: November 8, 1977. 

FOR FURTIIER INFORMATION CONTACT: 

James A. Smith <Office of Conservation). Room 307 Old Post Office Building, 12th and Pennsylvania Avenue 

NW .. Washington, D.C. 20461 <202-

566-4635J. 

Jim Merna <Media Relations). Room 

3104 Federal Building. 12th and Pennsylvania Avenue NW., Washington, 

D.C. 20461 <202-566-9833>. 

Robert D. R. de Sugny <Office of the 

General Counsell, Room 5116 Federal 

Building, 12th and Pennsylvania Ave- nue NW., Washsington. D.C. 20461 

(202-566-9750 or 202-566-9380). 

SUPPLEMENTARY INFORMATION: 

A. BACKGROUND 

The Federal Energy Administration 

<FEA) hereby amends Part 430. Chapter 

II of Title 10. Code of Federal Regulations, in order to prescribe test procedures for water heaters pursuant to sec- tion 323 <42 U.S.C. 6293> of the Energy 

Policy and Conservation Act <Pub. L. 

94-163>. Water heater test procedures were proposed by notice issued April 21, 

1977 <42 FR 21576, April 27, 1977), and a public hearing on the proposed test procedures was held on June 13, 1977. 

By notice issued May 24, 1977 < 42 FR 

27896. June 1, 1977), ~ established 

Subparts A and B of Part 430, Chapter 

II of Title 10. Code of Federal Regula- tions. Certain definitions and general 

provisions applicable to the energy con- servation program for appliances have 

been prODUJ)gated in SUbpart A. Final test~ procedures for room air condition- ers. dishwashers, television sets. clothes 

dryeri;, electric refrigerators, freezers. 

and electric refrigerator-freezers: have 

been prescribed in Subpart B and the 

final test procedure for clothes washers 

has been issued today by separate notice. 

Several other test procedures have been 

proposed for inclusion in Subpart B and 

FEA has also proposed a Subpart C for 

appliance energy efficiency improvement 

targets. An oJtline of the provisions of 

Part 430 which have so far been established, including provisions in today·s 

notice. is as follows: 

RULES AND REGULATIONS 

8t7BPUT A-GENDIJII. PllOVISlONI! 

Sec. 

430.1 Purpose and seope. 

430.2 Definitions. 

StnlP.\RT B-TF.sT Paocannu:s 

430.21 Purpose or scope. 

430.22 Test procedures for measures or energy consumption. 

(a) Refrigerators and refrfgcrntor-freezers. 

(b) Freezers. 

~cl Dishwashers. 

ld) Clothes dryers. 

(ei Wat~r heaters. 

lf) Room air conditioners. 

• • 

(h) Tl'levislon sets. 

(J) Clothes washers. 

430.23 Units to be tested freserved J. 430.2-1 Representations re~ardlng mcnsnres of ~nergy comnimptlon. 

(n) Refrigerators and refrigerator-freezers. 

( b) Freezers. 

(c) Dlshv:ashers. 

( d) Clothes drvers. 

( e) Water heaters. 

( !) Room nlr conditioners. 

(h) Television sets. 

(j) Clothes wa.sh ers. 

APPENDICES TO SUBPART B 

Appendix Al-Uniform Test Method for 

Measuring the Energy Consumption of 

Electric Refrigerators and Electric Refrigerator-freezers. 

Appendix B-Uniform Test Method for Mensuring the Energy Consumption of Freezers. 

Appendix C-Uniform Teso Method for Measuring the Energy Consumption of Dishwashers. 

Appendix D-Unlform Test Method for Measuring the Energy Consumption of Clothes 

Dryers. 

Appendix E--Unlform Test Method for Measuring the Energy Consumption of Water 

Heaters. 

AppendLx F-Unlform Test Method for Measuring the Energy Consumption of Room 

Air Condltlooo:rs. 

• • 

Appendix H-Uniform Test Method for Measuring the Energy Consumption of Television Sets. 

• • • 

Appendix J-Uniform Test Method for Measuring the Energy Consumption of Clothes 

Washers. 

B. DISCUSSION OF COMMENTS 

Comments were received from industry, consumers, and both Federal and 

State agencies. Those comments which were directly concerned with the labeling 

program under section 324 of the Act were forwarded to the Federal Trade 

Commission for consideration in developing labeling rules applicable to water 

heaters and they are not addressed here. 

The following is a discussion of U1e issues raised by those comments which 

pertained to the technical aspects of the 

proposed water heater test procedures. 

The comments have been analyzed by 

topic, rather than source, since in many 

cases the same or similar comments were 

received from more Umn one person. 

1. nu: BURDl:N OF TESTING 

Both the electric water heater manu- facturing industry and the oil water 

heater manufacturing industry com- mented that the proposed test procedure was undull' burdensome. however. their 

objections were ba.<sed on dil!eren

grounds. 

The basis of the electric water heater 

industry's objection was that testing 

costs would be prohibitive due to the ex- tremely large number of basic models 

they would be considered to manufacture 

under the test procedure's proposed definition of basic model. That definition 

categorized units as different basic models not only if they differed in factors 

such as tank capacity and insulation. bu

also if they differed in heater elemen

wattage or voltage ratings. As a conse- quence. one manufacturer commented 

that he theoretically offered 20,000 basic 

models. Another manufacturing firm 

stated that 144 different electrical input 

configurations are available for each of 

its electric water heater tank sizes. 

FEA finds that the test procedure. as 

proposed, would prove unduly burdensome for manufacturers o! electric water 

heaters with immersed heating elements 

in view of the large number of basic 

models that would have to be tested and 

the attendant high cost of testing. As a result, FEA has made changes to the proposed test procedure which are designed 

to reduce the burden of testing for man- ufacturers of electric water heaters with 

immersed heating elements. The changes are based on the fact noted at the hearing and in the comments that the electrical characteristics of an electric water 

heater with immersed heating elements 

have a minimal effect on efficiency for 

many purposes of the test procedure. It was therefore feasible to eliminate the 

distinction between units made on the 

basis of electrical characteristic-:;. This 

reduces the number of basic models that 

most manufacturers would be considered 

to produce to twenty according to testimony reeeived at the hearing. 

As a. consequence, several important 

changes in the test procedure have been 

made. First, the definition of a water 

heater basic model was revised to e.'tclude 

immersed heating elements from consideration. Second. the standby loss test 

for electric water heaters with immersed 

heat.mg elements \•;as revised to require 

the installation of .. standardized" heating elements m the water heaters to be 

tested. Third. the hot '\>-ater supply rating 

test and the recovery rate calculation 

were deleted from the test procedure. 

Finally. the method for determining t..11e 

power input for electric '1.-ater heaters 

with immersed heating elements v.-as changed. Each of these changes is discussed in detail in other sections of the 

preamble. 

The oil water heater manufacturing industry also commented that the test procedure was burden.~me as applied to 

them and they requested to be e.icempted 

from testing. They based their request on the fact that they represent only one pcrc<'nt or water heater wcs and the 

ffDEllAl l!IEGISTER, VOL 42, NO. 192-TUESDAY, OCTOBER 4, 1977 
C-TP-77-002 COMMENT 03

claim that their costs of testing would 

be higher than for manufacturers of 

other types of water heaters. The oil 

water heater manufacturing industry 

pre;;ented a cost analysis to demonstrate 

how the costs of testing would result in a much higher per unit cost increase for 

water heaters produced by a small manu- facturer of oil water heaters with small 

production runs than for a large manu- facturer of electric water heaters with 

large production runs. Thus. it was claimed, the much greater increase in 

price due to testing costs of oil water 

heaters over gas and electric water 

heaters would price the oil water heaters 

outside of the water heater market and 

lead to the demise of the oil water heater 

manufacturing industry. 

PEA finds that insufficient evidence 

has been produced by the oil water 

heater manufacturing industry to es- tablish grounds for excluding oil water 

heaters from the water heater test procedure. The cost analysis presented 1s a 

comparison of hypothetical cases. No 

evidence was presented to indicate that 

these hypothetical cases are representative of industry-wide conditions or that 

the costs would be any different for a. 

small electric water heater manufacturer. The sampling plan used 1n the cost 

analysis was not the sampling plan 

which appeared in the proposed test procedure and the assumption was made 

that each manufacturer would test his own units even though independent testing laboratories could be utilized. PEA 

rejects the recomm1mdation that on water heaters be excluded from the water 

heater test procedure at this time but 

may reconsider its position upon the submission of sufficient evidence that the 

test procedure is unduly burdensome or significantly more burdensome to oil 

water heater manufacturers as com- pared to similar sized manufacturers of 

other types of water heaters. 

2. FLUE REQUIREMENTS 

A comment made was that a specification is needed for the attachment of a ftue pipe extension to gas or oil water 

heaters having horizontal vent outlets. 

PEA concurs. The :Hue requirement 

specification in the proposed test procedure inadvertently addressed only water 

heaters with vertical vent outlets. Section 2.2 of Appendix E has been revised 

to incorpor!\te a specification for attaching a :Hue pipe to· a water heater with a horizontal vent outle£. 

Another comment made was that the 

test procedure should require that a direct vent water heater be set up as specified in the manufacturer's instructions 

that accompany the water heater. FEA 

concurs with this comment with the pro-

\"ii;o that the length of vertical :Hue pipe 

at.tnched to the water heater must not 

be greater than the specified five foot 

length. Section 2.2 of Appendix E has 

been rei.ised to incorporate this speclfi- ca tion. 

A third comment suggested the use of a longer flue pipe extension in the test 

procedure to better represent actual con- dit.ioni; of gas and oil water heater instalRULES AND REGULATIONS 

lat.ion in the home. While !t would be 

more representative of field conditions to 

use a longer length of ftue pipe for testing water heaters. e.g .. 15 feet instead of 

the specified 5 feet, the physical limitations of the manufacturer's test laborn.-

torles might make such a requirement 

unduly burden>:ome. FEA has therefore 

not adopted this .suggest.Ion. . 3. FUEL HEATING VALUE 

5-1

cation of exact heating values for 

and oil fuels. and (2) the burden o! h

ing to determine the heating value 

the fuel used in testing with an erro

no greater than one percent. 

In the proposed test procedwz hea

values for gas and oil fuels were in

vertently specified as exact values. 

actual heating value of the fuel used 

testing need only approximate the v

specified for that fuel in the propo

test procedure. Therefore. section 2.4 

Appendix E has b:.-en revised to spe

approximate heating values for gas 

oil fuels. 

PEA rejects the recommendations t

a standard heating value be assumed 

each fuel or that local utilities be re

upon to provide the heating value of 

fuel they supply. Fluctuations in 

heating value of fuels .supplied by ut

ties do occur as studies have shO'll.11. P

does not have sufficient information 

the capability of local utilities to p

vide accurate and meaningful heat

value information on the fuel or fu

they supply to warrant acceptance 

this means of determining fuel heat

value. On the other hand. FEA acce

the recommendation made at the pub

hearing that water heater manuf

turers be permitted the option of p

chasing "bottled" fuel which has had 

actual higher heating value determin

with an error of no greater than o

percent as certified by the supplier. Th

a. manufacturer would have the cho

of either purchasing a calorimeter, if o

is :i;iot already available. to determ

the actual heating value of the fuel 

fuels supplied by the local utility or p

chasing the necessary quantity 

"bottled.. fuel of a certified heati

value. Section 2.4 of Appendix E h

been revised to allow for the use 

"bottled'' gas or a tested oil of a certif

heating value in the test procedure. 

4. WATER TEMPERATURE RISE A..._D 

THERMOSTAT SETTING 

Several comments were made whi

questioned the specification of 90° F. 

the test procedure for the temperatu

rise through which a water heater und

test must heat the inlet water. One co

ment recommend that •"alues of te

perature rise be selected on the basis 

geographical regions to better refl

actual conditions where water heate

are marketed. In other words. the wa

heater test procedure should be regio

alized to account for different water i

let temperatures which result in diff

ent temperature rises in \-arious parts 

the country. FEA rejects this recomme

dation on the basis that it would requ

water heater manufacturers to condu

many more tests than currently requir

and it v;ould therefore be unduly burde

some. 

Many comments were directed tow~!d 

Section 2.4 of Appendix E. "Energy Supply." Moot of these comments concerned 

the heating values assigned to gas and 

oil fuels. One such comment was a rec- ommendation that a manufacturer of oil 

water heaters be permitted to conduct 

testing either .by using fuel oil with a presumably certified heating value of 

138,000 Btu per gallon or by determining 

the actual heating value of the fuel oil 

used in the test. FEA has assumed that 

the figure 138,000 cited in the comment 

above was a. typographical error in the 

comment and was supposed to be 138,500. 

the heating value o! fuel oil in Btu per 

gallon cited in the proposed test procedure. Another comment was a recom- mendation that the heating value of natural gas and propane should be designated as approximate net values. A com- r.:>ent was aJq made that specifying a hea~!ng valu;:; for natural gas of 1025 

Btu per standard cubic foot is unrealistic 

since the heating value of the natural 

gas suppl!ed by local utilities varies with 

geographic location. A manufacturing 

firm impl!ed that the requirement that 

the actual heating value of the natural 

gas used in the test be determined with an error no greater than one percent is 

unduly burdensome. This firm stated 

that it does not have the instrumentation available at its water heater manu- facturing plants to measure th:J heating 

value of the natural gas supplied by the 

local utilities. It has been this firm ·s practice to rely on the local utility to 

furnish on a.n "as needed" basis the 

heating value of the natural gas supplied. The firm recommended allowing 

the use of the gas supplied by the local 

utility for testing on the condition that iS 

identified by the utility as "natural gas." 

The firm also stated that its comments 

concerning the determination of the 

heating value of natural gas apply to 

propane gas as well. A comment was made that an ERDA report indicated 

that the heating value of fuel oil supplied by utilities may be as low as 120,000 

Btu per gallon. It was also pointed out 

that FEA did not state what type of test was to be used for determining the heating value of fuel oil. Th1s can have a dramatic impact on the results it \\'!l.S 

claimed. Finally, a comment recom- mended that the requirement that natural gas with a heating value of 1025 

Btu per standard cubic foot be used in 

the test be deleted. the reason being that 

the manufacturers performing the tests 

would have no control oYer the gas supplied by the utilities. 

The concerns expressed in U1e com- ments above fall into two categories: n) the proposed test procedures specifiComments "·ere made U1at the 90• 

temperature rise figure was too high an

should be lowered to reflect conditio

of operation advocated by FEA. i.e .• th

consumers should lower the thermost

settings on their water heaters to redu

energy consumption. FE.'\ rejects th

recommendation. Water heater therm

ffOEllAl REGISTER. VOL 42, NO. 192-TU!'SOAY, OCTOl!IR 4, 1977 
C-TP-77-002 COMMENT 03

Mats arc normally factory-set for gas 

heaters at 140° F. and at. 150° F'. for 

eleetric water heaters. The fact Umt these 

settings may be adjusted both up or clown b\· U1e installer or the homoov1mer 

is irrelevant to the determination of the 

cost of operation unless field surveys indicate that water heaters in representative use are normally adjusted to a different thermostat setting than at the 

time of purchase. No such field survey 

data was presented at the public hearing. 

Therefore. the test procedure uses tile 

average value of the two common factory. 

settings of water heater tilcrmostats. 

145° F .• as tile best approximation of the 

typical field water heater tilermo.stat setting. Since. as stated in the proposed 

test procedure. NBS has determined that 

the national average inlet water temperature is 55• F .. the difference between 

these two temperatures. 90° F .. is used a the water temperature rise in U1e test 

procedure. 

Further comments questioned FEA's 

selection of the inlet water temperature 

and t-he water heater ther:no.stat setting 

for the purposes of the test procedure. 

It is tn1e that these values. 70° F. and 

160° F .. respectively, do not represent 

field conditions as described by FEA. 

However. for some testing facilities, climatic conditions and/or other fact-Ors mav be such that for all or pa!"t of the 

year tap water temperatures will exceed 

55• F. Therefore. if a 55° F. inlet water 

temperature were to be specified- in the 

test procedure. these facilities would have 

t-0 purchase additional equipment to cool 

the available tap water prior to conducting a test. FEA believes that appropriate 

and comparable results can be obtained and the test procedure can be 

made less burdensome if water heaters are tested wit.'1 an inlet water temperature of 70° F. This inlet water temperature can normally be achieved in laboratories throughout the country at any 

time of Ye::tr without the need for cooling 

of the t-ap water. When the inlet water 

temperature of 70° F. is coupled with the 

requirement of a 90° F. v.-ater temperature rise, it results in a thermostat setting 

of 160" F. FEA finds that specifying an inlet water temperature of 70" F. and a 

water heater thermostat setting of 160° 

F. makes for a less burdensome test procedure which justifies their use. 

S. OIL WATER HEATER DEFilUTION 

Comments were made that the definition of an oil water heater in the proposed test procedure included oil water 

heaters predominantly used in commer- cial and industrial facilities. To exclude 

commercial and industrial type units and 

thereby make the types of oil water 

heaters covered by the test procedures 

comparable to the types of gas and electric water heaters covered, it was rec- ommended that the italue of the maxi- mum energy input rate. 172.500 But per 

hour in the proposed test procedure, be 

reduced to 103.875 Btu per hour which 

equates to an oil consumption rate of 

0.75 gallons per hour. It was further 

recommended that the value of the ma.·dmum energy input rate, 172,500 Btu per 

RULES AND REGULATIONS 

the proJ>C5ed definition of an oil v1ater 

heater be reduced from 50 gallons to 40 

gallons !or the a.me reason. 

PEA finds that the prol)O'.>ed definition 

of an oil water heater does cover units 

which are not normally purchased by 

individuals for household use. FEA has 

revised the proposed definition of an oil 

water heater to specify a ma."tlmum 

energy input rating of 103,875 Btu per 

hour <which equates to an oii consumption rale o! 0.75 gallons per hour> but 

has not revised the specified maxim= 

tank capacity value, 50 gallons. Willi the 

reduction of the maximum specified 

energy input rate. FEA finds that oil 

water heaters witil 50 gallons tank capacities are purchased by individuals for 

household use and therefore will be cov- ered by the test procedure. 

6. llOT WATER USE RATE 

Many comments questioned the daily 

hot water usage rate of 64.3 gallons per 

day specified in the test procedure to 

compute annual costs of operation. Most 

of these comments stated that this rate 

is too high to represent national average 

conditions. The reason for the apparent 

discrepnncy between the hot water usage 

rate specified by FEA and the studies 

cited in the comments is that FEA's 

usage rate is based upon representative 

conditions of use of the types of water 

heaters covered by the proposed test procedure. The comments cited national 

average use rates basc<l on household 

surveys which includes water usage data 

from households not serviced by the type 

of water heaters covered by the proposed. 

test procedures such as apartment dwellings serviced by large commercial water 

heaters. Including these types of households also lowers the number of persons 

per household from four, which is used. 

by FEA t-0 determine the daily hot water 

usage rate, to three, further contributing 

to a lower usage rate than that used by 

FEA. 

The hot water usage rate of 64.3 gnllons per day was arrived at from a survey 

of 50 gas and 50 electric utility com- panies for hot water and energy usage 

data for wateiheaters. Eighteen of these 

companies supplied metered data. Data 

obtained were normalized to a family of 

four and to a 90° F. temperature rise. 

The family size of four was taken from 

Census Bureau data as the average 

family size. The types of water heaters 

covered by the proposed test })rocedure are usually found in the service of single 

families. The use of a 90° F. temperature 

rise is explained in the previous section, 

Water Temperature Rise and Thermostat Setting. When the hot water usage 

rate of 64.3 gallons per day and the temperat·are rise of 90° F. are inserted int-0 

the water heater test procedure equations along with typical wat~r :t:eater 

performance parameters of recovery 

efficiency and standby loss as determined 

by laboratory tests, the result correlates 

well with typical home energy usage ns determined by U1e field survey. 

Therefore no changes to the proposed 

test procedure are considered. necessary 

with respect to the national ai;erage 

value o! hot water USAi;e-.. rate as used i

the calculation o! a:verng~ daily energ

consumption. 

'1. WATER Hl!:ATEP.S NOT con:JU:D BY nu: 

'!EST Pl!OO:DUl!ES 

Comments were ma.de that the pro

posed test procedures do not addre

solar water heaters. water heater/boile

combinations, or recirculating wate

heaters. Although th~ Energy Policy an

Conser11ation Act empowers the A.dmin!

trator to include otiler energy rourcE-

at, this time only those appliances pow

ered by electricity or fossil fuel.5 are sub

ject to testing. Therefore solar wat

heater manufacturers are not subject t

the Act. however, they may use the pre

ent test procedure w provide the con

sumer with inCormation concerning S-O

water heater performance if they s

cr.oose. 

&iler/watcr heater combinations ar

not. considered in thJs test procedure be

cause it is more appropriate to consld

such combinations as systems rath

than to attempt to consider the wat

heater and boiler components separatel

Since the water heater P-Ortion of a boi

er /water heater combination Is a second

ary system of the boiler, FEA finds Lh

it is more appropriate to include boil<e

water heater combinations with fu..

naces. Therefore the boiler/water hEate

type of appliance will be considered i

and subject to, the test procedure whic

is currently under development for fu

naces. 

The recirculating water heater is gen

erally used in large apartment building

or for ot.her commercial application

such as office buildings where long run

of piping from the water heater to ti

point of use would result in a long dela

period before hot water becomes avai

able at the fixture if a recirculating sy

tem were not used. Very few of thes

systems are sold t-0 the typical consume

and many are custom designed and cu

tom built. Therefore. the inclusion of re

circulating systems in the test procedur

is not recommended at th!s tlme. 

8. TEMPE:RATURE DIFFERENCE BETWEE

STORED WATER AND ROOM ttMPERATUR

AS USED IN THE CALCUI.ATIONS 

A comment stated that the mean t~m

perature dilference between the store

watP.r and ro-0m temperature is mor

likely in the range of 70-80° F. since mo

water hent~rs are located indoors. Th

proposed test procedure specilies that 

temperature difference .of 90° F. is to b

used as the temperature dilference be

tween the stored water and the room temperature. unlike all of the other i.--a

ucs specified in this test procedure. tlli

i.-nlue !or temperature difference is a de

rived i.-nlue rather than a i.--alue deter

mined by empiric-al data. l-"'EA has n

data on typical ambient temperature

where v:ater llC!ltC'rs are m.~talled. hov:

e\·er. the assumed imlue or 90° F .• when 

coupled with a hot water usage rate o

64.3 gallons per d:u· heated through a 90

P. temperature rise. will yield i.·alue:s o

calculated energy constm1ption tllnt

agree with nctual energy consumption 

RDIERAI. REGISTER. VOL 42, NO. 192-T\lltSOAY, OCT081Ell 4, 19n 
C-TP-77-002 COMMENT 03

<lilta for water heaters. A change in th!s 

value wou!rl ne-J;::.s..<;!tate a change in one 

of U1e otht'i·r p;:i,rameters such as hot 

water usage rate, water temperature rise, 

N<' .• in order to maintain agreement between the energy consumption calculated 

by use of the test procedure and actual 

energy consumed in representative use. Therefore. no change to the specified 

temperature difference between stored 

water and room temperature is recom- mended. 

!I. l\lEASUREl\IENT AND CALCUL.\TlON OF 

STANDBY LOSS 

Concerning the standby loss test, PEA concurs with the comments that standby 

locs for electric water heaters with immersed heating elements 1s virtually independent of energy input rating. 

Standby loss is a measure of the hot water 

storage performance of a water heater. 

This measure is primarily a function 

of the type and configuration of the tank 

insulation since most of the heat loss 

during standby 1s through the water 

heater jacket to the air surrounding the 

water heater. This is particularly true 

for electric water heaters which do not 

have flue losses and therefore their only 

other heat loss is through the inlet and 

outlet pipes when no heat traps are present. Because of this and because virtually 

all input energy to the heating elements 

goes towards heating water by the very 

nature of their design of haVing the 

heating elements in direct contact with 

the water in the water heater tank, 

standby loss will be the same for all electric water heaters with immersed heating elements of a given basic model. 

Therefore. PEA has adopted the recom- mendation that standby loss tests for 

electric water heaters with immersed 

heating elements be performed with the 

water heaters to be tested equipped with 

"standardized" heating elements. The 

procedure for determining standby loss 

for electric water heaters with immersed 

heating elements is presente<l in section 

3.4.2 of Appendix E. 

A suggestion was made ti.at determining standby loss in terms of the fraction 

of the heat content of the stored water 

lost per hour instead of in units of energy 

lost per hour hides the actual value of 

standby loss. FEA finds that the .determination of standby loss in terms of 

units of energy lost per hour can be 

accomplished by additional calculations 

which utilize the results obtained by the 

present test procedure. The determination of standby loss in term.:; of the fraction of the heat content of the stored 

\\·ater above room temperature lost per 

hour. however. allows the test for standby loss to be run without maintaining an exact 90° F. temperature difference b~t\\·een U1e stored water and the am- bient laboratory room temperature since 

t11c- te:-:L procedure compensates for am- bic-nt temperature and will yield U1e ~ame n\lue of standby loss as long as tile- ambient room temperature is wiU1in 

the range specified. 65° F. to 85° F. In 

order to directly determine standby loss 

in ab"olute terms of Btu per hour. the 

tc"t would need to be run under condiRULES AND REGULATIONS 

Uons of a constant room temperature of 

70" F. with stored water at 160° P. in 

order to obtain an exact 90° .,.. ~perature difi'erence. Alternatively, the stored. 

water temperature would have to be adjusted depending on the laboratory room temperature at the time of tests. 

Thus, the det~rminat!on of standby 

loss in terJru. of the fraction of the heat 

content of the stored water lost per hour 

makes for a less burdensome test procedure than the one which would have ti.> 

be developed if the suggestion that 

standby loss be determined in terms of 

units of energy lost per hour were to be 

adopted. In addition. it allowi; FTC to 

label the standby loss in the maimer suggested if the FTC deems it appropriate. 

Therefore. the suggestion has not been 

adopted. 

A comment was made that a calculation be included in the test procedure to · determine a cost of operation for a water 

heater on standby tn terms or do!lars per 

month. FEA finds such a cost can be determined from the test results of the 

current test procedure. Therefore, FTC can adopt this proposal to determine a cost of operation of a water heater on standby as part of their water heater 

labeling program, i! they so choose. 

Another comment suggested that a single test be conducted to determine 

both standby loss and recovery efficiency. 

The test recommended consists of a 12-

hour standby period followed by a draw 

period repeated enough tinles to provide 

acceptable accuracy. It was stated that 

the standby test proposed may not credit 

the savings to be expected from an electric ignition system and that recovery 

during dynamic conditions such as a wa- ter draw schedule may be different than 

recovery from 70° F. to 165° F., as proposed in the static test. Although no testing with intermittent ignition has 

been conducted by NBS to date, preliminary testing with a reduced pilot input 

rate has shown energy savings for a 72-

hour standby test. The question of accu- rately preclicting an energy saYings for 

electric ignition alone seems to be a moot 

point since that design option is not con- sidered economically practical unless it 

is accompanied by the use of a flue 

damper. In any event, NBS considers 

the test procedure as proposed to be suIficient to detect energy savings for intermittent ignition systems. FEA concurs with the NBS position. Therefore, this 

suggestion has not been adopted. 

10. MEASUREMENT AND CALCULATION OF 

RECOVERY EFFICIENCY 

A comment noted that a recovero.· efficiency of 100 percent is assumed for electric water heaters with inlmerscd heating elements in the calculation of standby loss yet a value for the recovery efficiency of an electric water heater with 

imnwrsed heating elements is calculated 

in a previous section. This apparent inconsistency results from the different 

methods used to calculutc recovery efficiency and standby loss between the 

electric and gas or oil fue!ed heaters. 

The recovery efficiency or an electric 

water heater with i..nmerscd heating elemeuls is very nf'.H to HIO percent since. as expl2.in~ in the sect.J<Jn or. standby 

loss, a..• .Immersed heaWig element delivers practically 10!; per.cent of llle ·"Hergy mput at th.<! point. o! use Ul ~.be 

water. To make a direct r.neasure~:ient 

of the recovery efficiency of such a water 

heater would be "Jery difficult. The procedure would require that the temperature 

of the water in the wa•er heater tank be 

determined very accurately. The !'ix 

thermocouple array that is required to 

be installed In the tank according to sec- tion :?.5 for the purpose of mea.surink 

water temperature is not sufficient f<:.•r 

the purpose of such a test. In fa-ct. attempts made to measure the recovery 

efficiency of an electric water heater with 

this thermocouple array could result in 

values of recovery efficiency greater than 

100 percent due to the error introduced 

by variations in water temperature which 

exist In the spherical portion at the bottom of the tank. An analysis would ila \'e 

to be made of the geometry o! the tank 

and additional thermocouples would have 

to be used in order to achieve the accu- racy requisite to directly measure re- covery efficiency. The requirements of 

making such a direct measurement would 

result in a test procedure v;hich wou!d 

be unduly burdensome for a manufacturer to conduct. 

Instead of requiring that U1e reco\·ery 

efficiency of an electric water heater with 

immersed heating elements be determined directly. the test procedure prnvides for calculating the recoven• e..fiiciency as one minus U1e ~t.andby lo.."Sei 

during recovery since standby loss is the 

only energy loss for such water heaters. 

This indirect method for determining re- coven· efficiency is more accurate than 

any direct method of detennination 

which would not be unduly burdensome. 

The standby loss measurement procedure is the same for each type of 

heater. However. the calculation differs 

in that an assignment of 0.98 for the . recoven· effciency. Er". is made for the 

electric water heater with immersed 

heating elements. Since one does not 

know the exact recovery efficiency for 

electric water heaters until the standby 

loss is measured and the standby less 

contains a correction b8.sed on reco...-e~· 

efficiency. there exists two equations with 

three unknowns. It therefore becomes 

necessary to assign a recovery efficiency 

in the standby loss equation. In the proposed t.est procedure. an assignment of 

1.00 was made. The actual ...-alue or the 

reco\·ery efficiency is more likely in the 

range of 0.97 to 0.99. Therefore. in order 

to reduce the error introduced into the 

standby loss equation for electric water 

heaters with immersed heating elements. 

PEA has changed the assigned value for 

recovery efficiet1cy from 1.00 to 0.98. 

One comment proposed that the "'·atcr 

heater tank should be preheatro for the 

purposes of performing the reco\·ery efficicncy te5t since oil fueled heaten; are affected more bs a cold start t~t than 

either gas or electric heaters. Elimination or the tank preheating test reduced 

the test time and the cost of testing. :!'.'BS 

testir..g has re\·ealed that the cold start 

FEDERAl l!EGISTER. VOL -12. NO. 192-lUi:SOAY, OCTOBER 4, 1977 
C-TP-77-002 COMMENT 03

5-Ul-t 

procedure gives test results 2 percent 

to 3 percent lower than if the tank were preheated for oil fueled water heaters. 

The preheated tank procedure ";\'Ould 

credit the recovery test with heat re- tained in the tank from the preheating 

of the tank. This does not represent ac- tual field conditions since heat input is 

not obtained free in actual use. However, 

the cold start test as proposed also does 

not represent actual use in the field. In 

the interest of reducing the time and the 

costs required to include a tank preheating test in the test procedure. the use of a tank preheating test has not been 

adopted. 

A comment stated that the static tests, 

without drawing water for measuring 

recovery efficiency. are not sufficiently 

accurate for determining the recovery 

efficiency of gas or oil fueled water heat- ers. Tests at NBS using a typical withdrawal schedule have shown a good 

correlation bet.ween the static test meas- urements and calculations compared to 

actual metered energy consumption for a 16-hour withdrawal schedule. Therefore. no change to the static test procedure has been made. 

A comment was made that a calculation be included in the test procedure 

to determine a cost of operation for a water heater during the recovery stage 

in terms of dollars per 1000 gallons of 

hot water delivered per month. Such a cost can be determined from the test 

results of the current test procedure. 

Therefore. FTC can adopt this proposal 

to determine a cost of operation of a water heater on recovery as part of their 

water heater labeling program. if they so choose. 

11. POWER INPUT !>ETERMINATION 

As a result of the change made to the 

definition of a basic model of a water 

heater, a method for determining the 

power input for an electric water heater 

with immersed heating elements had to 

be developed. Section 3.2.2 of Appendix 

E of this ·subpart presents the method 

for making this determination. The 

method does not require that power input measurements be made. The manu- facturer's assigned design energy ratings 

for the immersed heating elements that are installed in a water heater are used 

to calculate the power input term. Although this means of determining the 

power input for an ·electric water heater 

with immersed heating elements is an approximation of the actual value, the error that may be present will have little 

bearing on the two measures, recovery 

efficiency and average daily energy con- zumption, that use the power input term 

in their equations, by the nature of the 

equations themselves. The values determined from these equations are sufficiently insensitive to error in the power 

input term t-0 justify using an approximation for power input and not requiring 

that it be directly measured. 

12. HOT WATER SuPPLY RATI!'G AND 

RECOVERY RATE 

The hot water supply rating test and 

the recovery rate determination that 

RULES AND REGULATIONS 

were part of the prop06ed test procedure have been deleted. f:rom aie test 

procedure on the basis that, in theJr 

present f9rm, they would make the test 

procedure unduly burdf".nsome !or manu- facturers of electric water heaters with 

immersed heater elements to conduct. 

Unlike standby loss, hot water supply 

raiing and recovery rate determinations are very dependent on the actual wattage and location of the immersed heating 

elements installed in the water heater, 

the number of such elements installed, 

and the configuration of the auxiliary electrical system of the water heater 

which controls the operation of the heating elements. Testing for hot water supply rating and recovery rate would have 

to be done for all possible combinations 

of these factors which goes back to the 

problems associated with the proposed 

definition of a basic model of a water 

heater. 

Comments were made that the hot 

water supply rating of an electric water 

heater with immersed heating elements 

could be predicted for all basic models of 

electric water heaters in much the same way that standby loss could be predicted. 

No hot water supply rating prediction 

scheme was presented. Neither was any 

data submitted from which .a hot water 

supply rating prediction scheme might 

be developed. Without a hot water supply rating prediction scheme and without test data to verify that a particular 

prediction scheme is sufficiently accu- rate. FEA cannot consider making such a modification to the hot water supply 

rating test at the present time. 

In the case of recovery rate, the power 

input to the water heater must be determined. The current procedure for determining power input for electric water 

heaters with immersed heating elements 

is to accept the design value assigned by 

the manufacturer. Unlike recovery efficiency and average daily energy con- sumption. recovery rate is sensitive t-0 

error in the power input term and the 

approximations of power input determined in section 3.2.2 would introduce a 

potentially significant error into the determination of recovery rate which would 

be unacceptable. 

FEA finds that in the absence of a hot 

water supply rating prediction scheme 

and a recovery rate prediction scheme. 

the hot water supply rating test and the 

recovery rate determination must be deleted from the water heater test procedure at the present time. FEA recognizes 

that this deletion will eliminate an important measure of water heater performance from the test procedure. FEA 

also recognizes that without a hot water 

supply rating. or some other measure of 

hot water delivery perfomrnnce. the t~t 

procedure leaves a consumer '\\ith less 

than the best information to select a water heater which will satisfy his needs. 

Therefore. FEA plans to investigate prediction schemes for the detem1ination 

of hot water supply rating or for the determination of some other measure of 

hot water deli>·ery performar.ce for water 

heaters. The goal of this im-estigation 

will be to proi.ide consumers '\\ith a use-

!ul measure of hot water delh•ery per

formance for water heaters while no

Jmpasing unduly burdensome test re

quirements on any segment. of the wate

heater industry. 

FEA hereby invites the water heate

industry and any other interested partie

to provide input to FEA concerning thi

proposed investigation. This investiga

tion v:ill be completed by December l

1977. In its present form. nothing in thi

fin:tl test procedure prohibts a manufac

turer from makin" representations con

cerning the hot water ~upply rating o

any of his water beater products. 

13. SYMBOLS USED IN THE TEST 

PROC!:DUU: EQUATIONS 

Coments were ma.de that the symbol

used in the equations of the propose

test procedure exhibited Inconsistencie

which made Interpretation o! the equa

tions difficult. Further comments rec

omended that the symbols used b

revised in accordance v.ith standar

practices. FEA concurs. The equation.<

of section 4 of Appendix E o! this sub

part reflect the recommended change~

14. TESTING CONDmONS 

Comments an section 2.5 of the pro

posed test procedure pointed out tha

the requirement that thermocouples b

installed along the centerline of th

water heater tank may lead t-0 confusio

since for many gas and oil water heater

the flue is located at the centerline o

the tank. Section 2.5 has been revise

to eliminate this potential source o

confusion. 

In response to a. comment concen1in

the hook-up of the water heater inle

and outlet pipe connections to water sup

ply and delivery pipes, the test proce

dure has been revised to require a hea

trap type of configuration for •rnte

heaters with vertical inlet and/or outle

pipe connections. 

IS. CALCULATIONS OF THE ENERGY FAC!OR 

The proposed test procedure did no

clearly state the appropriate section o

Appendix E t-0 be used in the calculation 

of the energy factor in section 430..22 • e 1 

This resulted in misinterpretation oft.he 

use of the average daily energy consump

tion. Section 430.22Ce> has been cor

rected t-0 properly reference the apnro

priate section of Appendi.'C E. 

16. INDIRECT ENERGY CONSUMPTION 

A comment was made that the tes

procedure should account for the in

creased operating time and energy con- sumption of a furnace or air conditioner 

which is caused by gas and oil ·water 

heaters. The increased energy consumption arises from the fact that most gas and oil water heaters utilize interior air 

for combustion and draft maintenanc-e 

which is then vented out of the hou.<>e 

and replaced by the infiltration of ex- terior air which mu.st then be heated 

by the furnace or cooled by t.he air con- ditioner depending on the sea.son. TI.re 

loss of interior conditioned air contimir:< ev·en when the water heat<'r is not in the 

combustion stat<' due to the natural draft 

of the flue unless the water heatrr 1..-

ffDU!Al REGISTER, VOL 42, NO. 192-!UESDAY, OCTOl!Elt 4, 1977 
C-TP-77-002 COMMENT 03

RULES AND REGULATIONS 

equipped with a fiue damper which is 

usually not the case. to minimize the testing burden on manu- facturers. 

and dishwashers used both these ter

in a manner that could be confusi

and the Ianguage prescribed today is 

tended to eliminate this possibility. 

PEA is sensitive to such hidden costs 

of operation and will incorporate them 

whenever they are of sumclent magnitude to warrant the burden of additional 

testing designed to measure and quantify 

such costs. 

Test procedures prescribed under sec- tion 323 of the Act are intended ultimately to be used, for example, for labeling under section 324, for monitoring the 

progress of manufacturers toward accomplishing the energy efficiency imUntil.a labeling rule has been imp

mented pursuant to section 324. man

facturers are not required to test unl

they choose to make representations r

garding a measure of energy consum

tion. It. should be emphasized L'iat t

test procedures prescribed today app

only to the initial rating of a basic mod

Secondary costs have been included in 

the final test procedures for dishwashers 

and clothes washers, and in the proposed 

test procedures for dehumidifiers and 

furnaces. however. FEA has decided not 

to incorporate these costs in the water 

heater test procedure at this time. FEA 

bases its decision on data forwarded by 

NBS which indicates that the secondary 

costs represent only 2 percent of the cost 

of operation of a water heater and that 

the testing burden to account for such 

costs would be large. Furthermore, NBS 

has reported to FEA that the potential 

dollar savings achieved by the use of a direct vent system, which utilizes exterior air rather then int.erior air and 

thereby avoids imposing additional costs on furnaces or air conditioners, is not 

sufficient to pay for the cost of such devices. Only when direct vent systems are combined with preheating devices do 

they become economically viable and the 

test procedure, as currently written, will measure most of the increased efficiency 

of water heaters so eqUipped. Therefore 

there is little justification for mOdifying 

the test procedures at t.his time. 

. Anyone with information indicating 

i that direct vent systems alone are cur- rently economically justified for water 

heaters or that the cost a.<;Sociat.ed with 

the loss of interior conditioned air is 

greater than 2 percent of the cost of operation of a gas or oil water heater is 

hereby requested by FEA to submit such 

information. Should the assumptions on which FEA has based its· decision be 

shown to be incorrect, PEA will consider 

modifying the water heater test procedure to incorporate the secondary costs 

of operation. 

17. PRIMARY ENERGY LABELING 

While a comment suggested primary 

energy labeling, i.e., taking into consideration the energy consumed by a power 

plant t-0 produce the amount of electrical 

energy consumed by an appliance, the 

Energy Polley and Conservation Act 

specifically requires that the estimated 

annual operation cost of an appliance 

be calculated in terms of the retail cost 

of energy likely to be consumed in representative use. Therefore, this suggestion 

has not been adopted. 

18. NUMBER OF UNITS TO BE TESTED 

Some comments expressed objections 

to the sampling provision for water heat- ers. Proposed section 430.23<e> provided 

for sampling of each basic model to be 

tested when testing of water heaters is 

required by the Act or by program regulations of agencies :responsible for administering the Act. 'Ibis provision was 

intended both to provide an acceptable 

level of assurance that the test results 

::ire applicable to an units of a basic 

model for which testing is required and 

provement targets under section 325, and 

for enforcement testing under section 

326. These aspects of the appliance program have not. however, been implemented. It is quite possible that the objectives of appliance testing under each 

of these parts of the program, as well as the instructions as to how a test procedure should be applied. e.g., sampling of 

production tmits. may differ. FEA. NBS, 

and FTC are continuing to evaluate the 

appropriate method or methods for 

sampling the units t-0 be tested in order 

to comply with the statute and satisfy 

all of the di1ferent elements of the appli- ance program. 

While the various parts of the appli- ance program Identified above a.re not in 

effect at this time, section 323 Cc) or the 

Act provides: 

Effective 90 days after a test procedure rule 

applicable to a. covered product is preecrtbed 

under thls secti.on, no me.nu!a.cture'r, dlstr:lbutor, 'retailer or private labeler may make any 

representa.tion-

(1) In writing (Including a representation 

on a label), or (2) In any broadcast advertisement, 

respecting the energy consumption of' such 

product or cost of energy consumed by such 

product. unless such product has been tested 

In accordance with such test procedure and 

such representation fairly discloses the re- sults or such testing. 

In order to eliminate the problem discussed above associated with a general 

sampling provision, § 430.23 has been re- served in the :final test procedure, and 

sampling requirements which "apply only 

for purposes of advertising have been 

reorganized into § 430.24<e> of the final 

test procedures. Section 430.24.Ce) is similar to proposed§ 430.23Ce). but contains 

several revisions. Most notably, the units 

tested may now be either representative 

of production units, or actual production 

units. This change is intended to reduce 

the burden which might be caused by 

requiring post-production rating of basic 

models in every instance of testing pursuant to section 323(C) of the Act. 

19. MISCELLANEOUS 

After careful consideration of all 

the comments and further consultati

with NBS and FTC, FEA has incorp

rated some minor changes in the pr

posed test procedures in the final ru

that are not discussed above. 

C. REGULATIONS PRESCRIBED 

1. TEST PROCEDURES 

The test procedures for water hcat(

prescribed today are included in Su

pan B and are substantially the same 

thooe proposed with the exception of th

elimination of the hot water supply ra

ing test and the recovery rate determ

nation. As with the proposed procedure

test methods and conditions incorpora

the approach contained in American N

tional Standards Institute standard Z21

10.l-1971 and C72.1-1972. The te

procedure aJso uses the definition of th

term "oil" contained in the American S

ciety for Testing and Materials CASTM 

D396-71. Subsequent amendments 

either the standard or the suppleme

ma(ie by the standard setting organiz

tion will have no effect on the test proc

dure which can only be amended by PEA

Under the requirements of section 

<c> of the Federal Energy Administr

tion Act of 1974 <15 U.S.C. 761 et seq.l a

amended by section 9 of the Feder

Energy Administration Authorization A

of 1977 <Pub. L. 95-70), the Administra

tor is to consult with the Attorney Gen

eral and the Chairman of the Feder

Trade Commission concerning the im

pact on competition o! any rules pre

scribed by FEA which utilize or intorpo

rate any commercial standards. 

The Administrator has transmitte

copies of the :final test procedures fo

water heaters. which incorporate th

abo\"e mentioned commercial standards

to the Attorney General and the Chair

man of the Federal Trade COmmissio

for their comments concerning the im

pact of such standards on competition in 

accordance with section 32<c>. Neithe

individual has any comments nor do they 

recommend again.st the incorporation o

use of these commercial standards in the 

final test procedures for water hes.ters. 

2. GENERAL PROVISIONS 

In addition, certain technical changes 

have been made in sampling language. 

Specifically, there is to be 90 percent con- fidence that the true mean of any meas- ure of the basic model lies within ±10 

percent of the mean of such measure of 

the sample. Comments pertaining to 

several prop05ed test procedures criticized the language of the proposed sam- pling provision. These comments suggested that a sampling proYision should 

reier to the estimate of U1e mean rather 

than to the true mean. FEA has considered this suggestion and has determined 

that the language prescribed today is more t.echnlcnUy correct because the statistical measure "estimate of the mean .. and "mean of the sample .. are generally con.. ~uered to be identical. The final test 

procedures for room air conditioners 

Prescribed today are certain defini

tions applicable to water heaters which 

"'·ere pre\iously propos· .~ in Subpart A 

(41FR19977. May 14. 1976: 42 FR 15423

March 22. 1977l. Comments were re- ceh"ed regarding these definitions and 

the issues and changes ha\·e been discussed. earlier in this notice. All dcllnitions appearing in section 321 of the Act were incorporated by reference int-0 SubFtDIEl!Al l!EGISUI!, VOL 42, NO. 192-TUESDAY, ocrogn 4, 1977 
C-TP-77-002 COMMENT 03

part A of Part 430 in the final test. procedures for room air conditioners issued 

May 24, 1977 < 42 FR 27896, June l, 1977>. 

Detlnitlons of the terms "Administrator", "Btu" and "FEA" were also incorporated into Subpart A by the :ftnal room air conditioner test procedures. The definition of the term "basic model" for 

water heaters has been changed, as discussed above. Definitions of the terms 

"cutout" and "design power rating" have 

been added. 

It should be noted that some of the 

definitions prescribed today may be applicable to test procedures for other 

appliances. While these definitions are final. comments to the effect that any of 

these definitions are inapplicable to a. particular appliance will be evaluated to 

determine whether amendment or modification is appropriate. 

3. APPLICATION OF TEST PROCEDURES 

As discussed previously, the final water 

heater test procedures prescribed today 

must be applied before representations 

regarding a measure of energy consumption can be made. Because the purposes 

and needs of tha different elements of 

the nppliance program, such as labeling or targets, vary, application of the standard test methodology prescribed today 

may dit!er in some respects for each program element. Instructions on how to 

apply the standard test methodology will 

be proposed for comment as these other 

) element of the appliance program are developed. 

The requirements of~ 430.24<e) of the 

final regulations apply until such time as final labeling requirements for a particular measure of energy consumption 

and the associated test procedure application provision are prescribed. After 

that time, all representations regarding a measure of energy consumption covered 

by a labeling rule must be the same as represented on the label. 

D. UNIT COSTS OF E:s-ERGY 

Under section 323<b) (2) of the Act, 

FEA is to provide manufacturers information as to the representative aver- age unit costs of energy. This information was provided by notice issued 

July 11, 1977 (42 FR 36549, July 15. 

1977). 

E. PREEMPTION 

RULES AND REGULATIONS 

(Energy Policy and COn.l!i0ne.Uon Ad, Pub. L. ~163, a.s amended by Pub. L. ~ Jl'ederal Energy ~Uon ~of 1974 ~ 

L. 93-275, ms amended by Pub. L. ff-385; 

E.0.11790, 39 FB.23185.) 

Issued in Washington, D.C., Sept.em- ber 27. 1977. 

ERIC J. PYGI, 

Acting General Caunsel, 

Federal Energy Administration. 

1. Section 430.2 is amended by adding paragraph 15) as part o! the definition 

of "basic model" and by adding in appropriate alphabetical order the definition of "immersed heating element" and 

"water heater" to read as follows: 

§ 430.2 Definilions. 

"Basic model" means all units of a given type of covered product. or class 

thereof, manufactured by one manufacturer and: 

• 

<5> with respect to water heaters, 

which have the same primary energy source and which, with the exception of 

immersed heating elements, do not have 

any differing electrical, physical, or ftmctional characteristics that affect energy consumption. 

" "Immersed heating element"' means an electrically powered heating device 

which is designed to operate while totaJly 

immersed in water in such a manner that the heat generated by the device is 

imparted directly to the water. 

• • • 

"Water heater·• means an automatically controJled thermally insulated 

vessel designed for heating water and 

storing heated water, which utilizes 

either oil, gas, or electricity as the fuel or energy source for heating the water, 

which is designed to produce hot water 

at a temperature of less than 180°F., and 

which includes the foJlowing products: 

la) "Electric water heater" means a water heater which utilizes electricity as the energy source for heating the water, 

which has a manufacturer's specified 

energy input rating of 12 kilowatts or less at a voltage no greater than 250 

volts. and which has a manufacturer's 

specified storage capacity of not less 

than 20 gallons nor more than 120 gal- lons. 

2. Section 430.22 1s amended by add

ing a paragraph <e>. to read as follows

§ 430.2% Tat procedures !or mea~ur..,

of energy eoru;umption. 

" .. .. .. .. <e> Water Heaters. <1> The estimate

annual operating cost for water heater

shall hem For a gas or oil water heater. th

product of the representative averag

use cycle of 365 days per year times th

sum of <A> The product of the averag

daily auxiliary electrical energy con

swnption in kilowatt-hours per day, de

termined according to section 4.5.1 o

Appendix E of this subpart, times the 

representative aveni.i'e unit cost of elec

tricity in dollars Pe!' kilowatt-hour a.

provided by the Administrator plus lB> 

The product of the average daily gas o

oil energy consumpUon in Btu per day

detennilled a.ccord!Dg to section 4.5.2 o

Appendix E o! this subpart, times the 

representative average unit cost of ga

or oil, as appropriate, in dollars per Btu as provided by the Administrator. the 

resulting product then being rounded 

off to the nearest dollar per year. 

Iii) For an electric water heater, the 

product of the following three factors: 

<A> The representative average use cycle 

of 365 days per year, CB> The average 

daily energy consumption in kilowatthours per day, deterinlned according to 

section 4.5.4 of Appendix E of this subpart, and <C> The representative aver- age unit cost of electricity in dollars per 

kilowatt-hour as provided by the AdIninlstrator, the resulting product then 

being rounded off to the nearest dollar 

per year. 

<2> The energy factor for water heat- ers shall be-

(i) For u gas or oil water heater, the 

quotient of the daily water heating en- ergy consumption determined according 

to section 4.3 of Appendix E of this subpart divided by the product of the 

a.:erage dally energy COl:'.swnption as determined according to section 4.5.4 of 

Appendix E of this subpart times 3.41::? 

Btu per kilowatt-hours. the resultini:: 

quotient then being rounded on: to the 

nearest 0.01. 

<iD For an electric water heater. the 

quotient of the daily water heating en- ergy conswnption determined according 

to section 4.3 of Appendix E of this subpart divided by the product of the a'-er-

<b) "Gas water heater·• means a. wa- ter heater which utilizes gas a.s the en- ergy source for heating the water, whkh 

has a manufacturer's specified energy 

input rating of 75,000 Btu per hour or less, and which has a manufacturer's 

specified storage capacity of not less than 

20 gallons nor more than 100 gallons. 

. age daily energy consumption as determined according to section 4.5.4 of Appendix E of this subpart times 3,412 Btu 

per kilowatt-hours., the resulting quotient then being rounded off to the near- est 0.01. 

Today"s rulemaking prescribing final 

test procedures for water heaters supersedes any State regulation to the extent 

required by section 327 of the Act. Pursuant to section 327. all State regulations 

which provide for the disclosure of information with respect to any measure of energy consumption of water heaters or which provide for any euergy efficiency standard or similar requirement v.ith respect to energy efficiency or energy use of water heaters must now employ 

test procedures identical to those specified in today"s final rule. 

In consideration of the foregoing, 

Chapter II of Title 10. Code of Federal 

Regulations is amended as set forth 

below. elfecti.-e No.-ember 8, 1977. 

Cc) "Oil water heater" means a water 

heater which utilizes oil as the energy source for heatin6 the water, which has a manufacturer's specified energy input 

rating of 103,875 Btu per hour or less, 

and which has a manufacturer"s specified storage capacity of 50 gallons or less. 

(3) Ot.ber useful measures of energy 

consumption for water heaters shall be 

those measures or energy consumption 

for water heaters which the Administ.rator determines are likely to assist con- sumers in making purchasing decision.!< 

and which are derived from the appli- cation of Appendix E of this subpart. 

.. " 

3. Section 4~0.24 Is amended by adding a paragraph Ce), to read as follows: 

li'IDIERAL lllEG!STER, VOL 42, NO. 192-TUESDAY, OCTO!!Elt 4, 1977 
C-TP-77-002 COMMENT 03

:§ ·130.2 i Rl'presenlulions regarding 

nwasurl's o! energy consumption. 

e 

<e> Water heaters. (1) Except as provided in paragraph <e> (3) of thls sec- tion. no manufacturer, distributor, re- tailer. or private labeler of water heaters 

!nay make any representation with re- spect to or based upon a measure or measures of energy consumption described in § 430.22Ce> unless a sample of sufficient size of each basic model for 

which such representation is made has 

been tested in accordance with applicable provisions of this subpart such that, 

for each such measure of energy cm1-

sumption, there is at least 90 percent 

confidence that the true mean of such measures of the basic model ls within ±10 

percent of the mean of such measures of 

the sample. 

• 2 l The sample selection for paragraph 

<el <l > of this section shall be comprised of units which are production units, or which are representative of production· 

units, of the basic model being tested. 

(3> Whenever a rule applicable to 

water heaters has been prescribed under 

section 324 of the Act, this paragraph 

shall not apply to any label covered by 

such rule. and all representations of any measure of energy_ consumption covered 

by such rule shall be identical t-0 the measure of energy consumption on the 

label. .. .. 1, 4. Subpart B of Part 430 is amended to 

add an Appendix E, to read as follows: 

APPENDIX E--UNIFOR::'J: TEST METHOD FOR 

l\iEASURING THE ENERGY coxsu~tPrION' OF 

WATER HEATERS 

I. Definitions. _, 

1.1 "Cutout" means the moment in time 

when a water heater thermogtat !l:is acted to 

reduce the energy or fuel input to the heating 

e1ements or burners to a minimum. 

1.2 '"Design Power Rat!ng" means the 

nominal power rating that a water heater 

manufacturer assigns to a particular design 

of water heater heating element, expres"Cd in 

kilowatts. 1.3 ~Heat Trap·· means a device which can 

be Integrally connected, or independently at- tached, to the hot of cold water pipe connections of a water heater such that the device 

wlll develop a thermal or mechanical seal to 

minimize the recirculation of water due to 

natural thermal convection between the water heater tank and its water supply pipes 

and thereby reduce the heat Joss to the en- vironment from the hot water stored In the 

water heater. 

1.4 "Recovery Efficiency·• means the ratio of the beat Imparted to the water to-

(a) ·in the case of an electric water heater, 

the energy input to the heating elements 

during the period that the water tempera- ture is raised from the Inlet temperature to 

the final temperature with the tank filled to capacity. 

(bl In the case of a gas or oil v.-ater heat- er. the heat content o! the fuel consumed 

by the burners during the period the.t the 

v.-ater temperature ls raised from the Inlet 

temperature to the final temperature with 

t.he tank filled to caps.city. 

1.5 "Standby loss·· means the ratio of the 

heat 1068 per hour to the heat content of the 

stored. water above room teniperature. 

IUlES AND REGULATIONS 

e. !Int conditions. 

2.1 Installation. Install the water heater 

according to the manu!e.cturer's d.lrectlon.11 

on e. %.-1.nch-thk:k plywood platform supported by th.re& 2 x 4-lnch runners. For wa.ter 

heaters without Integral heat traps and with 

vertical Inlet and outlet pipe connections, 

lnsmU the Inlet and outlet piping with heat 

traps at the Inlet and outlet ports. Such heat 

traps may be made using pipe fittings such as elbows connected In such a fashion that 

the inlet and outlet piping make vertically 

upward runs just before turning downward to connect to the 1nlet and outlet ports. For water heaters with Integral heat traps or with horizontal Inlet and outlet pipe con- nections. install the Inlet and outlet piping 

in any convenient fashion. 

Sufficient clearance shall be allowed between the water heater surface and the piping (Including heat traps, If any) so that 

when the piping Is Insulated as specified below, the insulation does not contact any water heater surface except at the location 

where . the pipe connections penetrate the water heater jacket. Insulate the water heater inlet and outlet piping (Including heat 

tmps, If any) for a length o! !our feet from 

the connection at the water beater with a 

materl:il having a thermal resistance (R) 

vn!ue of not less than 

OF 

4 ··--·· --·-· lit uift'-hr 

2.2 Flue requirements for gas and oil 

u:atcr heaters. 

2.2.l Flue requirements fD'T" gas water 

heaters. For a gas water heater having a vertically discharging draft hood outlet. a 5 

foot vertical flue pipe extension having a 

diameter equal to the largest flue collar size 

of the draft hood shall be connected to the 

draft hood outlet. For a gas water heater 

having n horl7..ontally discharging draft hood 

outlet. a 90 degree elbow having a diameter 

equal to the largest flue collar size of the 

draft hood shall be connected to the draft 

hood outlet. A 5 foot length of flue pipe shall 

be connected to the elbow and oriented to 

discharge vertically upward. Perform au 

tests with the natural draft established by 

thl.s length of flue pipe. Direct vent gas water heaters should be lnstaUed with vent- ing equipment as specified ln the manu!ac- turer·s instructions: however, the vertical 

length of the flue pipe shall be no greater 

than 5 feet. 

54117 

68 and 72" F .• and at a gauge preg;ure of 

between 40 pounds per square inch and the 

maximum pressure s.peci!loo by the manu- facturer !or the water heater under test. I! 

the water supply pressure varies outside of 

these llm!ts during testing. the heater shall 

be Isolated by use of a shut-olf valve in the 

supply Jlne with an expansion tank installed 

In the supply llne downstream o! the shut-olf 

valve. There shall be no shut-olr means between the expansion tank and the water 

heater Inlet. 

2-4 Energy Supply. 

2.4.1 Electrical supply. For an electric water ht>ater and !or the aux1!1ary electrical 

system. 1! any, o! an oil or gas water heater, 

maintain the electrical supply voltage to within :!:l percent o! the center o! the voltage 

range specified by the v.:ater heater manu!acturer on the water heater nameplate throughout the entire operating portion of each te;t. 

2.4.2 Ga.q supply. 

2.4.2.2 Natural gas. For a gas water heater 

utilizing natural gas, maintain the gas »Upply at a normal Inlet test pressure imme<llately ahead o! all controls at 7 to 10 inches 

o! water column. If the water heater ls 

equipped with a gas appliance pressure regulator, the regulator outlet pressure at the 

normal test pres5ure shalt be approximately 

that recommended by the manufacturer. All 

burners shall be adjusted to achieve an 

hourly Btu rating that Is within :!:2 percent 

of the hourly Btu rating specl.fled by the 

manufacturer. Use natural gas with a higher 

heating value o! approximately 1.025 Btu per 

standard cubic !oot. Determine the actual 

higher heating value. Hn. in Btu per standard cubic foot, !or the natural gas to be 

used in the test, with an error no greater 

than :!:l percent, and use that value !or a.JI 

calculations Included herein. Alternath·eJy. 

the test can be conducted using .. l>ottlednatural gas of a higher heating va~ue of 

approximately 1.025 Btu per standard cubic 

foot as Jong as the actual higher beating 

·mJue of the l>ott!ed natural gas has been 

determined with an error no greater than :!:1 

percent as certified by the supplier. 

2.4.2.2 Propane gas. For a gas water 

heater utilizing !400pane •. maintain the gas 

supply at a normal in!et test pressure immediately ahead or all controls at 11 to 13 

inches of water column. If the water heater Is equipped with a gas appliance pressure 

regulator, the regulator outlet pressure at normal test pressure shall be approximately 

that recommended by the manu!acturer. All 

burners shall be adjusted to achieve an hourly Btu rating that Is within ±2 percent or the hourly Btu rating speclfled by the manufacturer. Use propane with a higher beating 

\"alue of approlt.lmately 2.500 Btu per stand· 

ard cubic foot. Determine the actu!Ll higher 

heating value. H,, In Btu per standard cubic 

foot. for the propanP. to be used tn the test. with an error no greater than ±1 percent. 

and use that value fur all calculations included herein. Alternatively, the test can be conducted using "bottled .. propane o! a 

higher heating \"alue of approximately 2.500 

Btu per .standard cubic foot as long s.s the 

actual higher hea;.ing "\"alt:e of the bottled 

propane has been determined with an error 

no greater than := l perc-cnt as c-ertlfted by 

the supplier. 

,. 2.4.3 Of! supply. For an '011 ~·ater heater 

2.2.2 Fine requirements fD'T" oil water heot- crs. For an oil fueled water heater. establish a draft at the flue collar equivalent to at least 

0.02 Inch of water column during periods of 

burner firing. For an oil water heater having 

a vertlca11y discharging draft hood outlet, 

establish the draft by using a sufficient length 

of flue pipe connected to· the water heater 

flue outlet and directed vertically upv;ard. 

For an oil water heater having a horizontally 

discharging draft hood outlet. a 90 degree 

elbow having a diameter equal to the largest 

flue collar size of the draft hood shaJJ be 

connected to the draft hood outlet. A length 

ot flue pipe sttftlclent to estab!Lsh the draft 

shall be connected to the elbow fitting and 

oriented to discharge vertically upward. Direct vent oil water heaters should be Installed 

with venting equipment as specl.fled In the 

manufacturer·s instructions. When celllng 

height Jlmlts the use or a sufficient length of 

vertical flue pipe for an oil water heater. a 

mechanical draft inducer may be used during 

periods of burner firing to establish the spe<:-

ifled draft at the flue collar. 

2.3 Water supply. Du.ring the entire test maintain the water supply to the water heater Inlet at " temperature of between 

_utilizing fuel oil. ms.lnt.\ln an uninterrupte<l 

supply or fuel ol! to the water heater during 

the entire operating portion of the t~t cycle. 

Use fuel oil with a heating "1"8.lue or approximately 138.500 Btu per_ gallon. Determine 

the actual hes!tng value. 11 •• in Btu per 

gallon for the fuel oil to be used in the 

test. with an error no greater than =: 1 per- cent. and use that value for all cstculatlon.q 

fla)fllAL lili:GISTEI, VOL 42, NO. 192-TIJIESDAY, OCTOl!IE!t 4, 1977 
C-TP-77-002 COMMENT 03

5·1118 

Included herein. Alternntlv1.'I\", the tests cnn 

be conducted using a tested· fuel oil wt th a 

ct-rtllled higher heating value of approximately 138,500 Btu per gallon ns long 11.11 the 

actanl higher heating value of the test fuel 

011 has been determined With an error of no 

,;renter thnn ±1 percent as certlfie<l by the 

supplier. 

2.5 Therm0<.'0uple installation. Install six 

thermocouples In.side the water heater tank. 

Pvsttlon each thermocouple measuring junction along a vertical line at the level of the 

center horizontal plane of each of six non- overlapp\ng sections or approximately equal 

volume !rom the top 1:o the bottoJn of the tnnk such that each thermocouple ls sur- rounded by water and as far as possible from 

nny heating element, anodic protective device, or a water tank or flue wall. The anodic 

protective device may be removed In order 

to Install t.he thermocouples and all testing 

mny be carried out with the device removed. 

Install thermocouples In bo!;h the coldwater Inlet pipe and the hot-water outlet 

pipe not more than sL"t Inches from the connections to the water heater, or, where thooe 

connections are Inaccessible, at thG closest 

nccesslble point to those connections. Install 

In the test room a thermocouple w.lth junction shielded against direct radiation from 

the water heater and positioned at the vertical mid-point or the henter at a perpendicular distance of approximately 24 inches 

from the surface of the water heater jacket. 

Provide an associated tempernture mensure- ment and Indicator system to assure that the 

temperature indicated for the thermocouple locntlon ls within ± 1 • F. of the actual 

temperature at that location. 

2.6 Setting the tank thermostat. Starting 

with a tank of unheated water. initiate normal operation of the water heater. After 

cutout, determine whether the maximum 

value of the mean tank temperature Is Within 

the range of 160° F. ±5° F. I! not. turn off 

the water heater, adjust the thermostat, 

empty the tank and refill with unheated water. then inltlnte normal operation of the 

water heater, and once again determine the 

maximum mean tank temperature after cutout. Repeat this sequence until the mnximum 

mean tank temperature after cutout ls w.lthin the range of 160° P. ±5° F., at which time 

the thermostat Is properly set. If a water 

heater has two thermostats. the thermostat 

which controls the upper heating element 

shall be set first to yield a m!l.l<imum water 

temperature of 160° F. ±5°. F. as measured 

by the topmost tank thermocouple after cut- out. The thermostat which controls the 

lower heating element shall then be set to 

yield a maximum mean tank temperature of 

160° F. ±5°P. after cutout. 

2.7 Fuel or energy consumptic-n measurement. Install one or more instruments which measure. as appropriate. and with an error no greater than ±1 percent. the quantity 

of electrical energy. 'natural gas. propnne or 

ft~el oil consumed by a water heater. Electrical energy consumption ls to be expressed 

In imits of kilowatt-hours. Natural gas and 

propane consumption shall be expressed In 

units of standard cubic feet. I.e .• measured 

cubic feet corrected to standard conditions 

of 60' F. temperature and 30 inches of 

mercury column pressure. Fuel oil consumption Is to be expressed in units of gallons. 

Also Install one or more Instruments which 

measure. as approprl.ate. and With an error no !'Teater than :=t percent. the rate of 

electrical energy. natural gas. propane or fuel 

oil consumption by a water heater. The rate 

of electrical energy consumption shall Ile expr~ed In units of kilowatts. The rate of 

-natural gas and propnne consumption shall 

RULES AND REGULATIONS 

be expressed In units of standard cubic feet 

p~r hour. The rate of !uel oll con6Umptlon 

shall. be expressed in unit.a of gallons per 

hour. 

2.8 Room aml:fent temperature. Maintain 

the ambient air temperature of the test room 

between 65° F. and 85" P. at all tlmes during 

the test, as measured according to section 

3.5. The nmblent air temperature during 

these tests shall not vary more than ±7" P. 

from the average ambient air temperature 

determined as the arithmetic average of t:l:le 

air temperatures measured periodically at Intervals no greater than 15 minutes 

throughout the duration of the test. 3. Test procedures and measurements. 

3.1 Tank storage capacity. Determine the 

storngt- capnclty, V. or the wnter heater under 

test, In gallons, according to the method specified In section 2.26 o! the Amerlcnn Natlonnl Standard for Gas Water Renters, 

Volume I, dcslgna'ted ANS Z21.10.l-1975. 

3.2 Power input determination. 

3.2.1 Pmcer input determination for gas 

and oil water heaters and electric water heaters with. other than tmmersed heating el$- ments. Inltlnte normal operation of the water 

heater, and by using the npproprlate Instrumentation specified In section 2.7 and the 

approprlnte fuel heating values of section 2.4, det.ermine the power Input, 

P, to the mnin burners (Including p!lot 

light power. If any) or heating elements of the water heater under test, In 

Btu per hour or kllowntts, as aproprlate. In 

addition, determine the power Input, pr to 

any ·auxillary electrical system of a gas or 

oil water heater when the main burners are 

In operation, in kllo-.vatts; and the power 

input, p,, to any auxlllary electrical system 

of a gas or oil water heater when the main 

burners are not In operation. In kilowatts. 

3.2.2 Power input determination for electric water heaters with. immersed heating 

elements. The power input, P, to the beating element of an electric wat.er heater with one immersed heating element sbnll be 

taken to be the design power rating of the 

heating element. For an electric water 

heater with dual !nunerscd heating elements. 

the power input. P, to the heating elements 

shall be taken to be the nrithmetlc mean 

of the design power ratings of the beating 

elements, If, In characteristic operation of 

the water heater, only one heating element 

will be energized at any time; otherwise, P 

shall be taken to be the sum of the design 

power rafJl.ngs of the heating elements. 

3.3 Recoi•ery efficiency. 

3.3.1 Recovery efficiency for gas an4 oil 

water heaters and electric water heaters 

1aith other than immersed heating elements. 

With the water heater turned off, fill the 

tank with water and eliminate any residual 

air remaining in the tank. If the mean 

tank temperature ls constant and w.lthin 

70• F.:=2• F., record the mean tank temperature, initiate normal operation of the water 

heater. and begin measuring the fuel or en- ergy flow to the burners (including pilot 

light fuel if any) or heating elements of 

the water heater using the appropriate instrumen tatlon specified in section 2.7. After 

cutout determine the maximum mean tank 

temperature and record the total fuel flow. 

Q•, for a gas or oil water heater. or the rot.al 

electr!rol energy flow, z •. to the hentlng ele- ments of an electric water heater, from lnitlntlon to cutout. Record the temperature difference. 11.T,. obtained by subtracting the 

initial from the finnl ma.'<imum mean tank 

temperature. 

3.3.2 Recovery efficiency for electric water 

l1catcrs 1cith immersed heating elements. The 

recovery efficiency for electt-lc ..-ater heaters 

wlt.h Immersed heating elements Is derived 

:rrom the results of the stan•.. y loss t~t.s o

section 3.4.2. 

3.4 Standby loss. 

3.4.1 Standby loss for ga'J and ,,;/ u·at...

heaters and electric tearer heaters tc!th or lie

than immersed heating dem.ents. _F..i;t.abl!s

nOl"lllA! water he.at.er operation within th

mutmwn mean tank temperature within th

rall€e specified in section 2.6 and with a

air ellminated from the tank. Begm th

standby 1065 test immediately aaer cutou

At the begmning of the standby l= tes

record the time, the me:i.n tank temperature

the ambient air temperature, and begi

measuring the fuel or energy flow 'to th

burners (lncludlng pilot light fuel 1! .any

or hentlng elements of the water heater u.-

lng the appropriate instrumentation speci

fied In section 2.7. 

At the end o! the first 15 mJnute int.en-a

and at the end o! each .subsequent 15 minut

Interval following t.he beginning of the tes

record the mean tank temperature and th

ambient air temperature. Continue thes

measurements until the end o! a 48 hou

period unless a main heating element o

burne1' Is on nt that time, ln which cas

continue these measurements until the fir

subsequent cutout. When the test is term

nated, record the total :ruel fiow, Q•. !or 

or oil water henter. or t.he total electrica

energy flow, z,, to the heating elements o

an electric wnter heater, !rom the beginnin

to the end of the test period. the final mea

tank temperature. the final amblent a

temperature, and the tlme duration, t. of th

standby loss test. in hours rounded of! to th

nearest tenth o! an hour, which elapse

from the beginning to the end of the tes

period. Calculate the average of the recorde

values of the mean tank temperatures an

of the ambient a1r temperatures taken at th

end of each time interval. including in eac

case the initial and final values. Determin

the difference, t.T,. between th6';e two aver

ages by subtracting the latter from the for

mer. and the difference. .:.T.. between th

final and Initial mean tank temperature

by subtracting the latter from the former. 

3.4..2 Standb11 Ioss for electric icater hea

ers with. immersed heating elements. A

water heaters to be tested must be equippe

with Immersed heating elements that have 

design power rating o! 4,500 watts unles

such a design power rating exceeds the mnx

mum design power rating specified by th

manufacturer for the water heater to b

tested, In which case the standbv loss tes

will be conducted with the wai.er heate

equipped with immersed heating elements o

a design power rating equal to the manu

facturer·s specified maximum design powe

rating. All water beaters capable of operatin

with dual immersed heating elements will b

equipped and tested with dual immerse

heating elements of equal design power rat

ing in accordance with the provisions speci

fied above. Tests shall be oonducted in ac

cordance with the same p~dures as thos

specified In section 3.4.1. 

3.5 Room temperature mea.«uremen

Room temperature wherever specified shal

be the temperature determined by using th

test room thermocouple described In ~tlon 

2.5. 

3.6 ;\fcan tank temp<:n1tun m~rement. 

Mean tnnk tempernture. the avera~ tem

perature of the water in a 'il&"ater beater tank

whettwr specliled shall be the mean of the 

temperatures determined by usinf: the six water heater tanlt tllermocouples described 

in seetlon 2.5. 

4. Calculation of dmred ;esults from tes

measur~rnts. 

4.1 Rttet'l'1Y efficirnrp. 

ffDERAl REGISTER, VOL 42, NO. 192-TUESDA"i", OCTO!IE!I. 4, 1977 
C-TP-77-002 COMMENT 03

4.1.1 Recoi·ery eff!cfency for ga.s and ofl 

irater heaters. For a gu or oU water heeter, 

calculate the recovery efilclency, Er, exp~ 

as n dimensionless quantity and defined M! 

\\ht•rt• 

p _kXVXt>T, 

··- Q,Xll ' 

J:..::.S\.:!.-l ntu iwr gallon ;)1'""., the nominal s1K'cific hrat of v."Ster. I"= tank capacity, d•trnninrd in a<rordance with s«"tion 3.1, expn'SS<'d In gallons. .l "f":=dilTorenC'tl botw .. n the Initial and final mi\!Ul tank tomprrntures. d•t•nnined in a<cordimce with &'<'lion 3.3.1. e.'tpr~ in °1-". Q. ~total fuel flow in the r..owry !Ml, d•termlned In !leCOrdance ";th section 3.3.1, expressed in appropriatr units. I l =lugbrr beating valuo for thr nppro1>rlnte fuel typo, If •• u •. or JI~ as drtemlint'd in accordance with ~t'Clion 2.-t. E.".tpressed in appropriate units. 

4.1.2 Recovery efficiency for electric water 

heaters with. other th.an immersed heating 

elements. For an electric water heater with 

other th~ immersed heating elements. calculate the recovery efilc!ency, E,, expressed 

as a dinienslonless quantity and defined as: 

kXVXAT1 E, Z,X3,412 Btu/kWh' 

where k, V. and AT1 a.re as d•fint'd In section 4.1.1. Z.= total el<"Ctrlcal energy Dow to the booting elemonL< in the recovery t<>st. dctrrmlnt'd In nccordance with section 3.3.1, expr"5Sed in kilmvntt-hours. 

4.1.3 Recovery efficiency for electric water 

heaters with immersed heating elements. For 

an electric water heater with immersed heating elements, calculate the recovery efilclency, 

Er, expressed as a dimensionless quantity and 

defined as: 

, SXkXVXAT, 

J:,=l- PX3,412 Btu/kWh' 

wh··re k and i · are as defined in Sl'Clion 4.1.1 S=standby loss, as calculalt'd in section 4.4.2. AT,=-15° F., the nominal average dl!Tcrcnce between the mMD tank tempernture and the ambient lillr tempernture during recovery. P=water hooter input power, determined In scc-0rd- ance with St""Ction 3.2.2, (":tprrsse-d in kilowatts. 

4.2 Standby loss. 

4.2.1 Standby loss for gas and oil water 

heaters. For a gas or oll water heater, calculate the standby loss, expressed in hour-' 

and defined as: 

wh.-ro k. V, and IT are as defmrd In s.,.,tion 4.1.1 Ji:. is as calculatffl in section 4.1.l Q, =I-Ota! fuel flow in the standby loss test, determined in acoordance with section 3.4.1, expressed In approprlat., units. A T,=ditfrrence betw .. n the average value or the moon tank temperature and the average value or the :m1blent air temperature during the standby Ires t<>st, drlennincd in n<cordance with section :l.4.l, expr.,.__""""1 in °F. A T1=ditTerence betwe<'tl the Initial and final mean tank temperatures. determined in acrord!M1C$ with 5""Uon 3.4.1, expressed In °F. I =duration or the standby loss test, determined in S<"rord:incc Vlitb section 3.4.l, expressed ha bt>tJ('S.. 

RULES AND REGULATIONS 

4.2.2 Standby k>si for electrk: iooter heater/I. For an electric water bem.t.er, calculate 

the standby loe8, B, exp~ m hour _. lllld 

defined as: 

~-~·_X3,412 Btu/kWh 

" - kXVX.lTiXl 

!!i.T, 

~T~XtXE/• 

whore k and I' are a.• dt•linrd in sretion 4.1.t. Z.=total ~IP<"triral em•rgy .:!ovr to the bt"-ating: E-lemt-nts: in th~ standby loss tl'Sl, det<'rmlncd in aerordan<e with Sl'etion 3.4.1 for eloctric watrr heaters Mth oth1·r thn.n immerSt>d heuting t'lements, or section :1.-1.:! for ele.clric watt>r bP-atl"TS with immersed 

hrn.tini;t cl.-mt:>nts, t"Xpr, ... ssed in kilowatl·hours.. .3.1'1=dilf .. ·rt"Hl"e lw-twe"n the avt:"rage volue of tho mPan tank temperstnr~ and the 11vrmge value or the amhirnt air tompt•r;~tnre during tltP stn.ndhy Joss l••·a, drterminl'<l in nc·cordnnr"" with SP-<·tion 3.4.1 for C"lrctric watt>r hf'at~rs with othrr than imnwrsrtl 

ht"a.ting elemeu1s. or section 3.4.2 for rlectric \\'aft>f' 

h•"a.tl"rs with imtth·rs<-d lw1uing e1Nnt~uts, £>:<· 

A 7',=Ji~f~~1~c~\!~~-~~~! ;::~\ ,r:iiiBl and finnl nwan tnnk tt>JUJK"raturrs. dt"Lf'rmim·d in H.t•t·on:.Jnnee withs~«·­

t ion -3A.1 for elr-ctri<.· w11tr.r hr-aters v.ith othf'r thnn tuun(\r:'ed h<'ntini;? rh'-ments. or section 3.4.2: for <'lrt'tric Wi\t<'"r h£"ntrrs with imnwrsed bl!ating c?e· nn~nts. axpn·s..~ in kilowntt-honrs. l=dnration of th• standby lo.s t•st, drlrrminrd fn nccordance with srction 3.4.1 for rll'etric watrr hoat•rs with ot hrr than lmtnrr""d heating elo- ments. or section 3.4.2 for E'lectric water heaters with innnersed htnling elements, expressed 'in hours. J"•=J·:. as cnlrulnlrd in Sl'ction 4.1.2 for r!N'lric watrr hN>tors with other thnn imm•'<>•cd hc•ating ole- mrnls, or 0.98 for t•l .. tric wnt..r hooters wllh Im· nwrs-l'd heating cli•ments. 

4.3 Daily water heating energy consumption. Calculate the daily water beating energy consumption, C .... the energy required 

to heat the nominal amount of hot water 

used daily, expres~ed in Btu p!.'r day and 

defined as: 

l:XUX~T., 

E. 

wherr 1: is as drfinf'Cl in ~ction 4.1.1. E,. is as calculated in :>eetion 4.1.1 for ~ns ant! oil water heaters, section 4.1.2 for e!('C'tric wst~r hr.aters with othf'r than immersed h•ating elrmcnts, or srction 4.1.3 for electric water be:i.tcrs with immersed heating element,. 

AT.=90" F., the nominal difforenee hct"l'l"Mn the water heater inlet and outlet water tPmperaturf".s. V=&-1.3 gallons per day. tho norninsl daily hot water usngo. 

4.4 Arerage hourly hot water storage en- ergy conS1Lmption. Calculate the average 

hourly bot water storage energy consumption, c.,. the average energy req\llred per 

hour t.o mal.ntain stored water temperature, 

expressed ln Btu per hour a.nd defined as: 

c •• =SXkXYX~T., 

wh~re k and V are as def med in H"Ction ·I.LI. 

sis as calculated in soction 4.:?.1 for itas nnd oil wat~r 

heatent, or section 4.2.2 for electric "l'l"Bt-' hN1tN>'. 

~1J

ATa-=~Y.t tlK' ns,m[nal ilif!...r""urP lLMv.t"fll tlw nl6

tank t1tm1N!"fa.tur(" awJ tlw J1luhwut au tt"Wl"'"

ture. 

4.5 Average dally energy comumption. 

4.5.1. Average tZ.atzy auzUiDr11 eZectrtc e

ergy consumption /Of' ga.s and oil wat

heaters. Par a gu or oil W11.t.er beatef', calc

!At& the average cb.l.ly awtilary electric

energy consumption, c-. expressed ldl

watt-hours per day and defined a.s: 

( • _,Cv1., . , (·>• hottri- ('~•) •u•-;:;- l'r/-.. /' -r I'•"~ -~ d:a~· - .f'. 

WbHP C ,.., i:i a.~ ,......i!t·nl:ttl"f'J in Sl"'f'f!on 4 ... 1. 

l'=poWtt input to tht" burn~ . .i ... i.-nnhwd in ~·c.c:nda1H.

with SN!tion 3.2..I~ t"Xpr.-:-.'(·'1 iu Htu JJ:d"f hour .. p,=p-OWPr input tu an''l au:uliary ..-l~rical s.y614."'lll duri

pt'"riods of ma.Jn hurrarr or .. -mtllm. d<"termined 

n.ceordancP with St'<:'tim1 :t.:t.1. t-XfJt't':'i..""'od in kilowatt..

p, =power input t-0 any amilbr)' rl.-.:·trieal system duri

perio<ls when the malu hurtwr ls not In 01...,.,.Uo

dt-lt"rtnined tu B!'t"ordao~:t· vdtb $l'CUon 3.:! 

e111rr:.setJ in kilowatts.. 

4.5.2 Average dally gas or oil e:-.ergy co

sumption for l}ll3 and oil 1.00tet· h.e:ate-ra. F

:i. b'IS or oil water heater, calculate the ave

age dally gas or oil energy consumption, C

as appropriate, expressed In Btu per day an

defined as: 

C "''is a.o; ('1\lcnlatPd in 5'.'CliO!l -1.:l. 

c •• is as calcula.tOO in Sf'<:'tion 4.4. Pis as defined in s«"tion 4.5.1. 

J,=daily- <'n<>rgy- c....Wt for a h.-4t tr.ii• iiL<tall..-d in th

outlet water connf"Ction of a \\"°!:ltt"r ht""41.er=I.:n1 Uu

Jl"f day- for watrr b..,.t..,.,. that have such a bE'at tra

a.< an integral part of th<' wat..r bt':\t"1", or %rro f

wat••r lwat~rs that do not. J ,=tlaily rnerg}" ~rrdlt for a hr:il trap IJL,tall<'d in th

inlet \\11.t.er connt"C'tion or a wa.tt"f" h'E"31tt=9S3 Bu

prr day for watrr hrot•rs that hai.-E> SU<'h a heat trn

a..' an intf1?rn). part or tht"' W3.ll"r b~..itrr. or zero fo

wutt-r heatt'rs that do not. 

4.5.3 At·erage daily energy consumptio

for gas and oil water heaters. For a gu or o

water heater, calculate the average dally en

ergy consumption, c,,. expressed In Btu pe

day and defined a.s: 

Cr-· c,+c .... '<~.-112 Rtu-'k\\'h, 

\\'hf"n~ 

C1is as C!l.kULltf'd in ~"C'tion 4_!,.,.~. 

Can is ns c:ilculatt-d in ~~tion -1 • .5.l. 

4.5.4 At•erage daily energy consumption 

for electric water heaters. For an electri

water heater, calculate the average dll.U

energy consumption. c,, expresaed 1n kilo

watt-hours per day and defined &S: 

c. 3,412 B~u/k\\"hx[ c .. ~+r •• x(24 h~~;s- f>X3,-tl;;;tu/kWh)-J ~-J.] c •• 1s as calculatrd in srction 4.3. •-is as calculated In section 4.4. J, Md J, are as defined In section 4.5.~. 

P=lnput power, determined In acroroarice with _.. tion 3.2.l for electric "'1lter heettts with otb« ~ 

immersed hMtlng elemenl3 or section 3.2.2 for el<lclrie water hMten with lmmmed b(laling elem~ts, eJC- pr-1 In lcllowatts. • 

{FR Doc.77-29000 Filed 10-3-77;8:45 am}