APPENDIX 7-C. LCC ENERGY USE CALCULATIONS

TABLE OF CONTENTS

7-C.1	 INTRODUCTION ....................................................................................................... 7-C-1 7-C.2	 WATER HEATERS .................................................................................................... 7-C-1 7-C.2.2 WHAM Equation....................................................................................... 7-C-1 7-C.2.3 WHAM Equation for Heat Pump Water Heaters ...................................... 7-C-4 7-C.2.3.1 Comparison of energy use calculations for heat pump water heaters........ 7-C-7 7-C.2.3.2 Calculating HPWH Cooling Effects .......................................................... 7-C-8 7-C.2.4 WHAM Equation for Gas Instantaneous Water Heaters ......................... 7-C-11 7-C.3 POOL HEATERS ...................................................................................................... 7-C-13 7-C.4 DIRECT HEATING EQUIPMENT .......................................................................... 7-C-13

LIST OF TABLES

Table 7-C.2.1 Comparison of HPWH Energy Use Results .............................................. 7-C-8

LIST OF FIGURES

Figure 7-C.2.1 Methodology for Calculating Energy Consumption for Water Heaters .... 7-C-1 Figure 7-C.2.2 Methodology for Calculating Storage WH Energy Consumption using WHAM Equation....................................................................................... 7-C-3 Figure 7-C.2.3 Methodology for Calculating Electricity and Fuel Consumption for Gas and Oil Storage Water Heaters ........................................................... 7-C-4 Figure 7-C.2.4 Methodology for Calculating HPWH Energy Consumption using Modified WHAM Equation ....................................................................... 7-C-5 Figure 7-C.2.5 Methodology for Calculating HPWH Cooling Effects.............................. 7-C-9 Figure 7-C.2.6 Methodology for Calculating Instantaneous WH Energy Consumption using Modified WHAM Equation ........................................................... 7-C-12

7-C-iAPPENDIX 7-C. LCC ENERGY USE CALCULATIONS

7-C.1 INTRODUCTION
This appendix contains the calculation methodology for calculating the energy use of residential water heaters, direct heating equipment, and pool heaters in the LCC Analysis.

7-C.2 WATER HEATERS

1 Water heaters energy consumption is calculated using the WHAM equation. Figure 7­ C.2.1 shows the methodology for calculating energy consumption for water heaters.

Engineering

Analysis Average Yearly Tank Temperature (Distribution) Average Monthly

Inlet Water Temperature Average Daily Hot Water Use

Operating Conditions Contractor

Survey Weather

Data

Average Monthly Ambient Temperature Draw Model

RECS Sample

Equipment Type WHAM

Modified WHAM

for HPWHs Storage WH

HP WH Monthly Energy Use

Data Sources RE EF

UA RECS Household Sampled

WHAM Calculations depedent on Equipment Type Inlet Water

Temp Methodolog y Well?

Equipment Parameters Pon Modified WHAM for Tankless WHs

Figure 7-C.2.1 Methodology for Calculating Energy Consumption for Water Heaters
7-C.2.2 WHAM Equation

1 The WHAM equation yields average daily water heater energy consumption (Q in ), and is expressed as follows:

7-C-1⎛ ⎟ + ⎞

⎟ ⎠ ( T in ) ( T amb ) vol × den C

− T UA ×

− T × × P tank tank 1

− 24 ( T amb ) Q in = ∗ UA

− T × × ⎜ ⎜ ⎝ tank RE P

on

Where:

Q in = total water heater energy consumption, Btu/day, RE = recovery efficiency, %, P on = rated input power, Btu/h, UA = standby heat-loss coefficient, Btu/h- o F, T

tank = thermostat setpoint temperature, o F, T

in = inlet water temperature, o F, T

amb = temperature of the air surrounding the water heater, o F, vol = volume of hot water drawn in 24 hours, gal/day, den = density of stored water, set constant at 8.29 lb/gal, and C

p = specific heat of stored water, set constant at 1.000743 Btu/lb- o F.

WHAM yields total water heater energy consumption (Q in ), which is the sum of fuel and electricity consumption. For gas-fired storage water heaters, gas-fired instantaneous water heaters, and oil-fired storage water heaters, it is necessary to disaggregate the electricity and fuel consumption. Figure 7-C.2.2 shows the methodology for calculating electricity and fuel consumption using WHAM. DOE calculated electricity consumption as follows:

Q electtricity = Q in × 

# ( P

aux − P

s tan dy 

# )

− P

s tan dy × 24 P

ON

Where:

Q electricity = electricity consumption, kWh, Q in = total water heater energy consumption, Btu/day, P ON = rated input power, kW, P aux = electricity demand when burner is on, kW, and P standy = electricity demand when burner is off, kW.

7-C-2Average Yearly TankTemperature(Distribution)Average MonthlyInlet WaterTemperatureAverage Daily HotWater UseAverage MonthlyAmbientTemperatureDraw ModelModeEnergyConsumptionDuring WaterHeatingEnergyConsumptionDuring StandbyWater HeatingStandbyAverage DailyTotal Energy Usefor MonthREUAWHAM CalculationPonHeat Capacity ofWaterDensity of WaterAverage Monthly Temperature DifferenceWater HeaterHeating LoadTest ProcedureParametersWH ON = 24 hrsEFFuel UseElec UseGas and Oil StorageWHs has both Fueland Elec UseFigure 7-C.2.2 Methodology for Calculating Storage WH Energy Consumption using WHAM Equation7-C-3DOE calculated gas consumption by subtracting electricity consumption from total water heater energy consumption (Q in ). Figure 7-C.2.3 shows the methodology for calculating electricity and fuel consumption for gas and oil storage water heaters.

Pstandby Mode Electricity Consumption Due to Water Heating

Energy Consumption During Standby Water Heating

Standby Paux (electronic ignition, controls, fan use) Pon

Average Daily Elec Use for Month Average Daily Total Energy Use for Month Fuel Use

Figure 7-C.2.3	 Methodology for Calculating Electricity and Fuel Consumption for Gas and Oil Storage Water Heaters
7-C.2.3 WHAM Equation for Heat Pump Water Heaters
For heat pump water heaters, energy efficiency and consumption is dependent on the ambient temperature. To account for this, DOE expanded the WHAM to utilize the calculation approach used in the NYSERDA Heat Pump Water Heater Site Screening Tool and DOE’s weatherization assistance program. 2, 3 The equation for determining the energy consumption of heat pump water heaters is similar to WHAM, but the RE is adjusted with a performance adjustment factor, which is a function of the average ambient temperature. A heat pump water heater operates either in heat pump mode or in electric resistance mode. DOE assumed that electric resistance mode of operation is used 100 percent when the monthly ambient temperature is below 32 o F. A heat pump water heater also operates in the electric resistance mode for part of the time even when the monthly ambient temperature is above 32 o F, due to the slower recovery rate of heat pump water heater compared to an electric resistance water heater. DOE determined that depending on household hot water consumption patterns, this type of operation occurs up to 10 percent of the unit’s operating time. Figure 7-C.2.4 shows the methodology for calculating the energy consumption of HPWHs using the modified WHAM equation.

7-C-4Average Daily HotWater UseAverage MonthlyAmbientTemperatureDraw ModelMode ofOperationWHAM (ElectricResistance Mode)WHAM (HeatPump Mode)ElectricResistanceModeHP ModeHeat Pump LoadFactor (% EnergyUse at HP Mode)Monthly EnergyUseREElectric. Res.= 98%EF = 2.2 @ 50 GalTankECR ModelDataREHeat Pump.= 242%UA = 1.82RECS SampledHouseholdRE AdjustmentFactorTest Data(JohnMaxwell)Monthly REHeat Pump.Calculation ofHPWH RuntimeFraction1% ER runtime per9500 Btu of DailyHot Water LoadEngineeringSpreadsheetTest Data/AssumptionPON,Electric. Res.= 4.5kWPON,HPWH= .5 kWAbove 32 F?YES(Calculate)HP Load =Adjusted RE *PONER Load = RE *PONNO (0% HP Mode)ECR ModelDataECR ModelDataFigure 7-C.2.4	 Methodology for Calculating HPWH Energy Consumption using Modified WHAMEquation7-C-5The HPWH WHAM equation is as follows:

⎡ HP frac ⎤ ⎛ ⎞ UA 

### ( T k − T amb 

### ) × tan _ RE × P A HPWH (1

− HP

_ f rac ) ⎢ ⎢ ⎢ ⎢ ⎢ ⎥ ⎥ ⎥ ⎥ ⎥ 1

− × + P

ON
, HPWH ⎜ ⎜ ⎝ ⎟ ⎟ ⎠ hpwh 

### ( T in 

### ) + 24 × UA × 

### ( T Tank − T amb 

### ) Q vol den C

− T × × × = in P k tan ⎛ ⎜ ⎜ ⎞ ⎟ ⎟ U

A 

### ( T k − T amb 

### ) × tan 1

− × RE P ON
, ER ⎝ ⎠ ⎣ ⎦ ER Where:

Q in = total water heater energy consumption, Btu/day, vol = daily draw volume, gal/day, den = density of water, set constant at 8.29 lb/gal, C

p = specific heat of water, set constant at 1.000743 Btu/lb- o F, T

tank = tank thermostat set point temperature, o F, T

in = inlet water temperature, o F, RE HPWH = recovery efficiency of heat pump mode, %, RE ER = recovery efficiency of electric resistance mode, %, UA = standby heat-loss coefficient, Btu/h- o F, T

amb = temperature of the air surrounding the water heater, o F, P ON,HPWH = rated input power of heat pump mode, Btu/h, P ON,ER = rated input power of electric resistance mode, Btu/h, PA hwh = performance adjustment factor,

= 0

. 00019738 × T 2

- 0

. 01842 × T + 1

. 3222625 , and amb amb HP_frac = fraction of water heating load that is satisfied by heat pump mode.

HP_frac is calculated using the following equation:

HP × P × RE × PA on ON
, HPWH HPWH hpwh HP

_ frac = HP

on × P ON
, HPWH × RE HPWH × PA hpwh + (1

− HP

on ) × P ON
, ER × RE ER

Where:

HP ON = fraction of time when heat pump mode is operating, %, vol × den × C P 

### ( T tan k − T in 

### ) ⎛ ⎜ ⎝ = 100

− ⎞ ⎟ ⎠ , when T amb >32oF and 0 when T amb <32 oF. 9500 = rated input power of heat pump mode, Btu/h, = rated input power of electric resistance mode, Btu/h, = recovery efficiency of heat pump mode, %, = recovery efficiency of electric resistance mode, %, = performance adjustment factor, %,

2 = 0

. 00019738 × T amb - 0

. 01842 × T amb + 1

. 3222625 , and = temperature of the air surrounding the water heater, o F. P ON,HPWH P ON,ER RE HPWH RE ER PA hwh

T

amb

7-C-67-C.2.3.1 Comparison of energy use calculations for heat pump water heaters
The energy use calculation used by DOE in this analysis is slightly different than either the NYSERDA Heat Pump Water Heater Site Screening Tool or DOE’s weatherization assistance program.

DOE’s weatherization assistance program calculates HPWH energy use by using the following formula:

vol × den × C P 

### ( T tan k − T in 

### )

= Q in EF × (1 + PA )

Where:

Q in = total water heater energy consumption, btu/day, vol = daily draw volume, gal/day, den = density of water, lb/gal, C

p = specific heat of water, Btu/lb- o F, T

tnk = tank thermostat set point temperature, o F, T

in = inlet water temperature, o F, EF = energy factor, and PA = performance adjustment factor, %.

The performance adjustment factor is given by the following formula:

3 2 o 

### PA = 0.00008 × T amb 

### + 0.0011 × T amb 

### − 0.4833 × T amb 

### + 0.0857, when T amb 

### > 32 F
1
o 

### PA = − 1, when T amb 

### ≤ 32 F EF

The NYSERDA Heat Pump Water Heater Site Screening Tool calculates HPWH energy use by using the following formula:

⎡ ⎢ ⎢ ⎢ ⎢ ⎢ lfhp

hpa (1

− lfhp ) ⎤ ⎛ ⎞ ⎟ ⎠ ⎟ + UA 

### ( T k − T amb 

### ) × tan 1

− ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ × ⎜

⎜ ⎝ E

F P HP 

### ( T

− T in 

### ) + 24 × UA × 

### ( T Tank − T amb 

### ) Q vol den C × × × = in P k tan ⎛ ⎞ 

### ( T 

### ) UA

− T × k amb tan 1

− × ⎜

⎜ ⎝ ⎟ ⎟ ⎠ E

F P ⎣
r r where,

Q in = total water heater energy consumption, Btu/day, vol = daily draw volume, gal/day, den = density of water, lb/gal, C

p = specific heat of water, Btu/lb- o F, T

tank = tank thermostat set point temperature, o F,

7-C-7T in = inlet water temperature, o F, UA = standby heat-loss coefficient, Btu/h- o F, T

amb = temperature of the air surrounding the water heater, o F, P HP = rated input power of heat pump mode, Btu/h, P

R = rated input power of electric resistance mode, Btu/h, EF r = resistance mode energy factor, EF hpa = heat pump mode adjusted energy factor,

2 = EF hp × 

# ( 0

. 00019738 × T amb - 0

. 01842 × T amb + 1

. 3222625 

# ) , and lfhp = fraction of water heating load that is satisfied by heat pump mode, %, rthp × P HP × EF hpa = rthp × P HP × EF hpa + (1

− rthp ) × P R × EF R rthp = fraction of run time by heat pump mode (96.4%).

Table 7-C.2.1 shows a comparison of energy use results for the DOE modified WHAM method used in this analysis, NYSERDA Heat Pump Water Heater Site Screening Tool method, and DOE’s weatherization assistance program method.

Table 7-C.2.1 Comparison of HPWH Energy Use Results

Calculation Methodology Average Annual Energy Use (kWh/y) % Diff from method used in this analysis DOE modified WHAM 1343

- NYSERDA method 1445 +7.6% Weatherization program 1095 -18.4%
7-C.2.3.2 Calculating HPWH Cooling Effects
Heat pump water heaters draw heat from the space in which they are located. Thus, when the heat pump water heater is located in the conditioned space, its use affects the load that needs to be met by a home’s space heating and air conditioning equipment. When the home is being heated, use of the heat pump water heater increases the heating load, and when it is being cooled, such use decreases the cooling load.

To account for these indirect effects on home energy use, DOE estimated the impact on space heating and air conditioning energy consumption only for homes with a water heater installed in the conditioned space. For these homes, DOE estimated the impact on space heating in heating months only (when indoor temperature is 10 degrees greater than the average outdoor temperature), and the impact on air conditioning for cooling months only (when indoor temperature is 5 degrees below the average outdoor temperature). Figure 7-C.2.5 shows the methodology DOE used to calculate the amount of cooling added (i.e., heat removed) by the heat pump water heater.

7-C-8Determination of HPWH Operating HoursTank ThermostatTemperatureAverage MonthlyInlet WaterTemperatureAverage Daily HotWater Use(Draw Model)Heating orCooling MonthCooling Outputinto ConditionedSpaceNo Heating/CoolingDecerasedCooling LoadPon(1,700 Btu/hr)Average MonthlyIndoor Temperature(thermostat)Thome <(Toutdoor + 5)= CoolingWater HeatCapacityWaterDensityAverage Monthly Temperature DifferenceThome >(Toutdoor + 10)= HeatingAverage Daily WaterHeater Heating LoadCooling Capacity(3,500 Btu/hr)Additional HeatingLoadNo AdditionalHeating/CoolingRE(rated vol depedantand Adjusted forTamb)Average MonthlyOutdoor TemperatureInstallationLocationConditionedspaceNon-conditioned spaceRECS SampledHouseholdOvercooling Effect(Decreases Loadby 1/3)Heating Fuel andEquipment TypeCooling EquipmentTypeHeatingEquipmentEfficiencyCooling EquipmentEfficiencyAEO 2007*RECSSample*No AdditionalHeating/CoolingSpace Heating & Cooling Eqp ImpactsDetermination of Heating or Cooling MonthFigure 7-C.2.5 Methodology for Calculating HPWH Cooling Effects7-C-9The equation for calculating the cooling input (amount of cooling added or heat removed) by the heat pump water heater is as follows:

vol × den × C p 

## ( T tan k − T in 

## ) CoolingInput = CoolingCap HPWH × P × R E × PA ON
, HPWH HPWH HPWH Where:

CoolingInput = amount of cooling added by the HPWH, Btu/h, vol = daily draw volume, gal/day, den = density of water, lb/gal, C

p = specific heat of water, Btu/lb- o F, T

tank = tank thermostat set point temperature, o F, T

in = indoor air temperature, o F, P ON,H,PWH = rated input power, Btu/h, RE = recovery efficiency, %, PA hwh = performance adjustment factor, %, and CoolingCap HPWH = cooling capacity of heat pump water heater, Btu/h.

3 P ON for heat pump water heaters is 500 W (1704 Btu/h), and CoolingCap HPWH is 3500 2 4 Btu/h. DOE used RECS 2001 data for each household to determine the primary heating system and fuel used to heat the house as well as the cooling system type. DOE then assigned an energy efficiency to each type of equipment to determine the energy use loss (from heating) or gain (from cooling). DOE based the energy efficiency of the heating and air conditioning equipment 5 on the stock-average values for 2015 given in EIA’s Annual Energy Outlook 2008 . To account for the times during the summer months when the air conditioner is not operating (e.g., at night), DOE reduced the estimated cooling benefits from the water heater by one-third (8 out of 24 hours).

The analysis results that the HPWH cooling effect affects 46.4% of households for an average of 6.1 months in the heating season and 29.6% of households for an average of 4.7 months in the cooling season. Overall 49.8% of households are affected either in cooling and/or heating season. The average net cost from heating is about $82 per year, while the average net benefit for cooling is about $10 per year. These impacts are account for in the LCC and NIA analysis.

Alternatively, the household can install a venting system to vent the cold air out of the conditioned space. DOE estimates that the average cost for this installation would be similar to the average cost of adding a new plastic venting system for condensing furnaces which is found 6 in the 2007 Furnace and Boilers Rulemaking. The cost would be $442.56. In addition, there would be the cost of adding an exhaust venting fan of about $100. The total cost would then be about $542.56. These estimates are provided for comparison only and are not applied in the analysis.

7-C-107-C.2.4 WHAM Equation for Gas Instantaneous Water Heaters
For instantaneous water heaters, DOE calculated the energy use using a similar approach to storage water heaters, but modified to account for the absence of storage tank and adjusted for the performance observed in the field compared to that measured with the DOE test procedure. Figure 7-C.2.6 shows the methodology for calculating the energy consumption of instantaneous water heaters using the modified WHAM equation.

The instantaneous water heater WHAM equation is as follows:

where:

Q in = total water heater energy consumption, Btu/day, ⎛ ⎜ ⎜ ⎝

vol = daily draw volume, gal/day, den = density of water, lb/gal, Cp = specific heat of water, Btu/lb- o F, T

tank = tank thermostat set point temperature, o F, Tin = inlet water temperature, o F, RE = recovery efficiency, %, PA iwh = performance adjustment factor = (100% – 8.8%), %, Q

p = pilot input rate, Btu/h, Q out = heat content of the water drawn from the water heater, Btu/h, and Pon = rated input power, Btu/h,.

The performance adjustment factor for instantaneous water heaters ( PA iwh ) is derived 7 from a study conducted for California Energy Commission (CEC) in 2006. According to this report, current DOE test procedure energy factor calculations for gas-fired instantaneous water heaters overvalue their performance by not accounting for the impact of small hot water draws and heat exchanger “cool down” on overall performance. The DOE test procedure measures six successive draws of about 10 gallons, while actual field use has many more draws many of which are small draws. The 8.8% depredating factor is derived using average hot water use profiles and weighting more efficient “hot starts” and less efficient “cold starts”. ⎟ + ⎞

⎟ ⎠ 

## ( T in 

## ) Q

P

ON vol den C

− T × × p P k 

## ( T amb 

## ) tan 1 24 Q

− Q

− T × × × = in Tank p RE PA hpwh ×

7-C-11Average Yearly TankTemperature(Distribution)Average MonthlyInlet WaterTemperatureAverage Daily HotWater UseAverage MonthlyAmbientTemperatureDraw ModelModeEnergyConsumptionDuring WaterHeatingEnergyConsumptionDuring StandbyWater HeatingStandbyAverage DailyTotal Energy Usefor MonthREQpModified WHAM CalculationPonHeat Capacity ofWaterDensity of WaterAverage Monthly Temperature DifferenceWater HeaterHeating LoadWH ON = 24 hrsFuel UseElec UsePerformanceAdjustment FactorFigure 7-C.2.6 Methodology for Calculating Instantaneous WH Energy Consumption using Modified WHAM Equation7-C-127-C.3 POOL HEATERS

8 DOE calculated the average annual fossil fuel energy, E F , using the DOE test procedure:

E F = BOH × Q IN − ( POH

− BOH ) × Qp

Where:

BOH = burner operating hours, h/year, Qin = pool heater input rate, kBtu/h, POH = pool operating hours, h/yr, and Qp = pilot light input rate, kBtu/yr.

The burner operating hours are calculated using the pool heater heating load (PHHL) for each sample household. The equation for BOH is as follows:

LOAD BOH = Q IN × E t Where:

BOH = burner operating hours, h/year, PHHL = Pool heater heating load, btu/year, (see Appendix G), Q in = pool heater input rate (kBtu/h) =250 kbtu/h, E t = thermal efficiency.

DOE calculated the electricity consumption using the following formula

E F = BOH × PE

− ( POH

− BOH ) × PE

s tan by

Where:

BOH = burner operating hours, PE = electrical consumption of the heater, POH = pool operating hours (h/yr), and PE stby = electrical consumption of the heater when the burner is off.

7-C.4 DIRECT HEATING EQUIPMENT
DOE calculated the average annual fuel energy, E F , for single-stage direct heating 9 equipment using the following formula from the current revision of DOE’s test procedure:

E F = BOH SS × ( Q IN − Q P ) + 8760 × Q P

Where:
7-C-13BOH = burner operating hours, h/year, Q in = input capacity (at the max input rate), kBtu/h, 8760 = hours per year, and Q

p = pilot light input rate, kBtu/h.

The burner operating hours are calculated using the calculated house heating load (HHL) for each sample household (see Appendix G). The equation for BOH is as follows:

BOH SS = A × HHL

− 4160 × Q P × η

U ,

Where:

BOH = burner operating hours, h/year, 100,000 A = , 341,000 × P E + 

## ( Q in − Q P 

## ) × η

U HHL = house heating load (see Appendix G), btu/year, PE = maximum electric power, kW, 4160 = average heating season hours, Q P = pilot light input rate, kBtu/h,

η U = 2950 AFUE × η

SS × Q in , and 2950 × η

SS × Q in − AFUE × 2.033 × 4600 × Q P η SS = steady state efficiency, %.

The steady state efficiency ( η SS ) is calculated by solving for η SS in the equation given in section 4.1.17 of the DOE test procedure using the following equation and the values for the parameters D F , D S , P F , and L J given in the DOE test procedure:

AFUE + 1.78 × D + 189 × D

− 129 × P

− 2.8 × L + 1.81 η = F S F J

SS 0

. 968

The electricity consumption is calculated as follows:

stby PBOH PE BOH ElectUse ×−+×= ) (8760
W here:

ElecUse = DHE electricity consumption, kWh/year, BOH = burner operating hours, h, PE = electricity demand when the product is firing, kW, and P stby = DHE standby power draw (when the burner is OFF), kW.

7-C-14REFERENCES

1. Lutz, J., C. D. Whitehead, A. Lekov, D. Winiarski, and G. Rosenquist, WHAM: A Simplified Energy Consumption Equation for Water Heaters. , in 1998 ACEEE Summer Study on Energy Efficiency in Buildings. 1998: Asilomar, CA. p. 1.171-1.183.

2. Kelso, J., Incorporating Water Heater Replacement into The Weatherization Assistance Program, May 2003, 2003. D&R International, Ltd. Information Tool Kit.

3. Maxwell, J., Heat Pump Water Heater Economic Model, personal communication. NYSERDA

. 2004.

4. U.S. Department of Energy - Energy Information Administration, Residential Energy Consumption Survey: 2001 Public Use Data Files, 2001.

< http://www.eia.doe.gov/emeu/recs/recs2001/publicuse2001.html >

5. U.S. Department of Energy - Energy Information Administration, Annual Energy Outlook 2008 (Revised Early Release) with Projections to 2030 , 2008. Washington, DC. Report No. DOE/EIA-0383(2008).

6. U.S. Department of Energy - Energy Efficiency & Renewable Energy, Technical Support Document: Energy Efficiency Standards for Consumer Products: Residential Furnaces and Boilers , 2007. Washington, DC.

7. Davis Energy Group, Measure Information Template: Tankless Gas Water Heaters, May 18, 2006. Docket # 07-BSTD-1.

< http://www.energy.ca.gov/title24/2008standards/prerulemaking/documents/2006-05­ 18_workshop/2006-05-11_GAS_WATER.PDF >

8. Department Of Energy, Appendix E to Subpart B of Part 430-Uniform Test Method For Measuring The Energy Consumption Of Water Heaters . filed as "WH Test Procedure 10 CFR 430 subpart B, Appendix E".

9. Department Of Energy, Appendix O to Subpart B of Part 430-Uniform Test Method For Measuring The Energy Consumption Of Vented Home Heating Equipment . filed as "WH Test Procedure 10 CFR 430 subpart B, Appendix E".

7-C-15