Note:

On and after November 27, 2023, any representations made with respect to the energy use or efficiency of all pool heaters must be made in accordance with the results of testing pursuant to this appendix. Until November 27, 2023, manufacturers must test gas-fired pool heaters in accordance with this appendix, or appendix P as it appeared at 10 CFR part 430, subpart B revised as of January 1, 2021. Prior to November 27, 2023, if a manufacturer makes representations of standby mode and off mode energy consumption, then testing must also include the provisions of this appendix, or appendix P as it appeared at 10 CFR part 430, subpart B revised as of January 1, 2021, related to standby mode and off mode energy consumption.

1. Definitions:

Active electrical power means the maximum electrical power consumption in active mode for an electric pool heater.

Active mode means the condition during the pool heating season in which the pool heater is connected to the power source, and the main burner, electric resistance element, or heat pump is activated to heat pool water.

Coefficient of performance (COP), as applied to heat pump pool heaters, means the ratio of heat output in kW to the total power input in kW.

Electric heat pump pool heater means an appliance designed for heating nonpotable water and employing a compressor, water-cooled condenser, and outdoor air coil.

Electric resistance pool heater means an appliance designed for heating nonpotable water and employing electric resistance heating elements.

Fossil fuel-fired pool heater means an appliance designed for heating nonpotable water and employing gas or oil burners.

Hybrid pool heater means an appliance designed for heating nonpotable water and employing both a heat pump (compressor, water-cooled condenser, and outdoor air coil) and a fossil fueled burner as heating sources.

Input capacity means the maximum fuel input rate for a fossil fuel-fired pool heater.

Off mode means the condition during the pool non-heating season in which the pool heater is connected to the power source, and neither the main burner, nor the electric resistance elements, nor the heat pump is activated, and the seasonal off switch, if present, is in the “off” position.

Output capacity for an electric pool or spa heater means the maximum rate at which energy is transferred to the water.

Seasonal off switch means a switch that results in different energy consumption in off mode as compared to standby mode.

Standby mode means the condition during the pool heating season in which the pool heater is connected to the power source, and neither the main burner, nor the electric resistance elements, nor the heat pump is activated.

2. Test method.

2.1 Active mode.

2.1.1 Fossil fuel-fired pool heaters. The test method for testing fossil fuel-fired pool heaters in active mode is as specified in section 2.10 of ANSI Z21.56 (incorporated by reference, see § 430.3), with the following additional clarifications.

1. Burner input rate is adjusted as specified in section 2.3.3 of ANSI Z21.56,

2. Equilibrium is defined as in section 9.1.3 of ASHRAE 146 (incorporated by reference; see § 430.3)

3. Units are only to be tested using a recirculating loop and a pump if: the use of the recirculating loop and pump are listed as required; a minimum flow rate is specified in the installation or operation manual provided with the unit; the pump is packaged with the unit by the manufacturer; or such use is required for testing.

4. A water temperature rise of less than 40 °F is allowed only as specified in the installation or operation manual(s) provided with the unit.

2.1.2 Electric resistance pool heaters. The test method for testing electric resistance pool heaters in active mode is as specified in ASHRAE 146 (incorporated by reference; see § 430.3).

2.1.3 Electric heat pump pool heaters. The test method for testing electric heat pump pool heaters in active mode is as specified in AHRI 1160 (incorporated by reference; see § 430.3), which references ASHRAE 146 (incorporated by reference; see § 430.3).

2.1.4 Hybrid pool heaters. [Reserved]

2.2 Standby mode. The test method for testing the energy consumption of pool heaters in standby mode is as described in sections 3 through 5 of this appendix.

2.3 Off mode.

2.3.1 Pool heaters with a seasonal off switch. For pool heaters with a seasonal off switch, no off mode test is required.

2.3.2 Pool heaters without a seasonal off switch. For pool heaters without a seasonal off switch, the test method for testing the energy consumption of the pool heater is as described in sections 3 through 5 of this appendix.

3. Test conditions.

3.1 Active mode.

3.1.1 Fossil fuel-fired pool heaters. Establish the test conditions specified in section 2.10 of ANSI Z21.56 (incorporated by reference; see § 430.3).

3.1.2 Electric resistance pool heaters. Establish the test conditions specified in section 9.1.4 of ASHRAE 146 (incorporated by reference; see § 430.3).

3.1.3 Electric heat pump pool heaters. Establish the test conditions specified in section 5 of AHRI 1160. The air temperature surrounding the unit shall be at the “High Air Temperature—Mid Humidity (63% RH)” level specified in section 6 of AHRI 1160 (incorporated by reference, see § 430.3) (80.6 °F [27.0 °C] Dry-Bulb, 71.2 °F [21.8 °C]).

3.1.4 Hybrid pool heaters. [Reserved]

3.2 Standby mode and off mode. After completing the active mode tests described in sections 3.1 and 4.1 of this appendix, reduce the thermostat setting to a low enough temperature to put the pool heater into standby mode. Reapply the energy sources and operate the pool heater in standby mode for 60 minutes.

4. Measurements

4.1 Active mode

4.1.1 Fossil fuel-fired pool heaters. Measure the quantities delineated in section 2.10 of ANSI Z21.56 (incorporated by reference; see § 430.3). The measurement of energy consumption for oil-fired pool heaters in Btu is to be carried out in appropriate units (e.g., gallons).

4.1.2 Electric resistance pool heaters. Measure the quantities delineated in section 9.1.4 of ASHRAE 146 (incorporated by reference; see § 430.3) during and at the end of the 30-minute period when water is flowing through the pool heater.

4.1.3 Electric heat pump pool heaters. Measure the quantities delineated in section 9.1.1 and Table 2 of ASHRAE 146 (incorporated by reference; see § 430.3). Record the elapsed time, tHP, from the start of electric power metering to the end, in minutes.

4.1.4 Hybrid pool heaters. [Reserved]

4.2 Standby mode. For all pool heaters, record the average electric power consumption during the standby mode test, PW,SB, in W, in accordance with section 5 of IEC 62301 (incorporated by reference; see § 430.3). For fossil fuel-fired pool heaters, record the fossil fuel energy consumption during the standby test, Qp, in Btu. (Milli-volt electrical consumption need not be considered in units so equipped.) Ambient temperature and voltage specifications in section 4.1 of this appendix shall apply to this standby mode testing. Round the recorded standby power (PW,SB) to the second decimal place, and for loads greater than or equal to 10 W, record at least three significant figures.

4.3 Off mode.

4.3.1 Pool heaters with a seasonal off switch. For pool heaters with a seasonal off switch, the average electric power consumption during the off mode, PW,OFF = 0, and the fossil fuel energy consumed during the off mode, Qoff = 0.

4.3.2 Pool heaters without a seasonal off switch. For all pool heaters without a seasonal off switch, record the average electric power consumption during the standby/off mode test, PW,OFF = PW,SB, in W, in accordance with section 5 of IEC 62301 (incorporated by reference; see § 430.3). For fossil fuel-fired pool heaters without a seasonal off switch, record the fossil fuel energy consumption during the off mode test, Qoff (= Qp), in Btu. (Milli-volt electrical consumption need not be considered in units so equipped.) Ambient temperature and voltage specifications in section 4.1 of this appendix shall apply to this off mode testing. Round the recorded off mode power (PW,OFF) to the second decimal place, and for loads greater than or equal to 10 W, record at least three significant figures.

5. Calculations.

5.1 Thermal efficiency.

5.1.1 Fossil fuel-fired pool heaters. Calculate the thermal efficiency, Et (expressed as a percent), as specified in section 2.10 of ANSI Z21.56 (incorporated by reference; see § 430.3). The expression of fuel consumption for oil-fired pool heaters shall be in Btu.

5.1.2 Electric resistance pool heaters. Calculate the thermal efficiency, Et (expressed as a percent), as specified in section 11.1 of ASHRAE 146 (incorporated by reference; see § 430.3).

5.1.3 Electric heat pump pool heaters. Calculate the COP according to section 11.1 of ASHRAE 146. Calculate the thermal efficiency, Et (expressed as a percent): Et = COP.

5.1.4 Hybrid pool heaters. [Reserved]

5.2 Average annual fossil fuel energy for pool heaters. For electric resistance and electric heat pump pool heaters, the average annual fuel energy for pool heaters, EF = 0.

For fossil fuel-fired pool heaters, the average annual fuel energy for pool heaters, EF, is defined as:

EF = BOH QIN + (POH−BOH) QPR + (8760 − POH) Qoff,R Where: BOH = average number of burner operating hours = 104 h, POH = average number of pool operating hours = 4,464 h, QIN = input capacity, in Btu/h, calculated as the quantity CF x Q x H in the equation for thermal efficiency in section 2.10.1 of ANSI Z21.56 (incorporated by reference; see § 430.3) and divided by 0.5 h (For electric resistance and electric heat pump pool heaters, QIN = 0.), QPR = average energy consumption rate of continuously operating pilot light, if employed, = (QP/1 h), QP = energy consumption of continuously operating pilot light, if employed, as measured in section 4.2 of this appendix, in Btu, 8760 = number of hours in one year, Qoff,R = average off mode fossil fuel energy consumption rate = Qoff/(1 h), and Qoff = off mode energy consumption as defined in section 4.3 of this appendix.

5.3 Average annual electrical energy consumption for pool heaters. The average annual electrical energy consumption for pool heaters, EAE, is expressed in Btu and defined as:

(1) EAE = EAE,active + EAE,standby,off (2) EAE,active = BOH * PE (3) EAE,standby,off = (POH−BOH) PW,SB(Btu/h) + (8760−POH) PW,OFF(Btu/h) where: EAE,active = electrical consumption in the active mode, EAE,standby,off = auxiliary electrical consumption in the standby mode and off mode, PE = active electrical power, calculated as: = 2Ec, for fossil fuel-fired heaters tested according to section 2.10.1 of ANSI Z21.56 and for electric resistance pool heaters, in Btu/h, = 3.412 PEaux,rated, for fossil fuel-fired heaters tested according to section 2.10.2 of ANSI Z21.56, in Btu/h, = Ec,HP * (60/tHP), for electric heat pump pool heaters, in Btu/h. Ec = electrical consumption in Btu per 30 min. This includes the electrical consumption (converted to Btus) of the pool heater and, if present, a recirculating pump during the 30-minute thermal efficiency test. The 30-minute thermal efficiency test is defined in section 2.10.1 of ANSI Z21.56 for fossil fuel-fired pool heaters and section 9.1.4 of ASHRAE 146 (incorporated by reference; see § 430.3) for electric resistance pool heaters. 2 = conversion factor to convert unit from per 30 min. to per h. PEaux,rated = nameplate rating of auxiliary electrical equipment of heater, in Watts Ec,HP = electrical consumption of the electric heat pump pool heater (converted to equivalent unit of Btu), including the electrical energy to the recirculating pump if used, during the thermal efficiency test, as defined in section 9.1 of ASHRAE 146, in Btu. tHP = elapsed time of data recording during the thermal efficiency test on electric heat pump pool heater, as defined in section 9.1 of ASHRAE 146, in minutes. BOH = as defined in section 5.2 of this appendix, POH = as defined in section 5.2 of this appendix, PW,SB (Btu/h) = electrical energy consumption rate during standby mode expressed in Btu/h = 3.412 PW,SB, Btu/h, PW,SB = as defined in section 4.2 of this appendix, PW,OFF (Btu/h) = electrical energy consumption rate during off mode expressed in Btu/h = 3.412 PW,OFF, Btu/h, and PW,OFF = as defined in section 4.3 of this appendix.

5.4 Integrated thermal efficiency.

5.4.1 Calculate the seasonal useful output of the pool heater as:

EOUT = BOH[(Et/100)(QIN + PE)] where: BOH = as defined in section 5.2 of this appendix, Et = thermal efficiency as defined in section 5.1 of this appendix, QIN = as defined in section 5.2 of this appendix, PE = as defined in section 5.3 of this appendix, and 100 = conversion factor, from percent to fraction.

5.4.2 Calculate the annual input to the pool heater as:

EIN = EF + EAE where: EF = as defined in section 5.2 of this appendix, and EAE = as defined in section 5.3 of this appendix.

5.4.3 Calculate the pool heater integrated thermal efficiency (TEI) (in percent).

TEI = 100(EOUT/EIN) where: EOUT = as defined in section 5.4.1 of this appendix, EIN = as defined in section 5.4.2 of this appendix, and 100 = conversion factor, from fraction to percent.

5.5 Output capacity for electric pool heaters.

5.5.1 Calculate the output capacity of an electric heat pump pool heater as:

QOUT,HP = k * W * (Tohp−Tihp) * (60/tHP) where k is the specific heat of water, W is the mass of water collected during the test, Tohp is the average outlet water temperature during the standard rating test, Tihp is the average inlet water temperature during the standard rating test, all as defined in section 11.2 of ASHRAE 146, and tHP is the elapsed time in minutes of data recording during the thermal efficiency test on electric heat pump pool heater, as defined in section 9.1 of ASHRAE 146.

5.5.2 Calculate the output capacity of an electric resistance pool heater as:

QOUT,ER = k * W * (Tmo−Tmi) * (60/30) where k is the specific heat of water, W is the mass of water collected during the test, Tmo is the average outlet water temperature recorded during the primary test, and Tmi is the average inlet water temperature record during the primary test, all as defined in section 11.1 of ASHRAE 146, and 60/30 is the conversion factor to convert unit from per 30 minutes to per hour. [80 FR 813, Jan. 6, 2015, as amended at 88 FR 34703, May 30, 2023]