Note:

On or after September 27, 2021, any representations made with respect to the energy use or efficiency of room air conditioners must be made in accordance with the results of testing pursuant to this appendix.

Prior to September 27, 2021, manufacturers must either test room air conditioners in accordance with this appendix, or the previous version of this appendix as it appeared in the Code of Federal Regulations on January 1, 2020. DOE notes that, because representations made on or after September 27, 2021 must be made in accordance with this appendix, manufacturers may wish to begin using this test procedure immediately.

0. Incorporation by Reference

DOE incorporated by reference the entire standard for AHAM RAC-1, ANSI/ASHRAE 16, ANSI/ASHRAE 41.1, ASHRAE 41.2-1987 (RA 1992), ASHRAE 41.3-2014, ASHRAE 41.6-2014, ASHRAE 41.11-2014 and IEC 62301 in § 430.3. However, only enumerated provisions of AHAM RAC-1 and ANSI/ASHRAE 16 apply to this appendix, as follows:

(1) ANSI/AHAM RAC-1:

(i) Section 4—Testing Conditions, Section 4.1—General

(ii) Section 5—Standard Measurement Test, Section 5.2—Standard Test Conditions: 5.2.1.1

(iii) Section 6—Tests and Measurements, Section 6.1—Cooling capacity

(iv) Section 6— Tests and Measurements, Section 6.2—Electrical Input

(2) ANSI/ASHRAE 16:

(i) Section 3—Definitions

(ii) Section 5—Instruments

(iii) Section 6—Apparatus, Section 6.1—Calorimeters, Sections 6.1.1-6.1.1., 6.1.1.3a, 6.1.1.4-6.1.4, including Table 1

(iv) Section 7—Methods of Testing, Section 7.1—Standard Test Methods, Section 7.1a, 7.1.1a

(v) Section 8—Test Procedures, Section 8.1—General

(vi) Section 8—Test Procedures, Section 8.2—Test Room Requirements

(viii) Section 8—Test Procedures, Section 8.3—Air Conditioner Break-In

(ix) Section 8—Test Procedures, Section 8.4—Air Conditioner Installation

(x) Section 8 —Test Procedures, Section 8.5—Cooling Capacity Test

(xi) Section 9—Data To Be Recorded, Section 9.1

(xii) Section 10—Measurement Uncertainty

(xiii) Normative Appendix A Cooling Capacity Calculations—Calorimeter Test Indoor and Calorimeter Test Outdoor

If there is any conflict between any industry standard(s) and this appendix, follow the language of the test procedure in this appendix, disregarding the conflicting industry standard language. Scope

This appendix contains the test requirements to measure the energy performance of a room air conditioner.

2. Definitions

2.1 “Active mode” means a mode in which the room air conditioner is connected to a mains power source, has been activated and is performing any of the following functions: Cooling or heating the conditioned space, or circulating air through activation of its fan or blower, with or without energizing active air-cleaning components or devices such as ultra-violet (UV) radiation, electrostatic filters, ozone generators, or other air-cleaning devices.

2.2 “ANSI/AHAM RAC-1” means the test standard published jointly by the American National Standards Institute and the Association of Home Appliance Manufacturers, titled “Energy Measurement Test Procedure for Room Air Conditioners,” Standard RAC-1-2020 (incorporated by reference; see § 430.3).

2.3 “ANSI/ASHRAE 16” means the test standard published jointly by the American National Standards Institute and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers titled “Method of Testing for Rating Room Air Conditioners and Packaged Terminal Air Conditioners,” Standard 16-2016 (incorporated by reference; see § 430.3).

2.4 “ANSI/ASHRAE 41.1” means the test standard published jointly by the American National Standards Institute and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers titled “Standard Method for Temperature Measurement,” Standard 41.1-2013 (incorporated by reference; see § 430.3).

2.5 “ASHRAE 41.2-1987 (RA 1992)” means the test standard published jointly by the American National Standards Institute and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers titled “Standard Methods for Laboratory Airflow Measurement,” Standard 41.2-1987 (RA 1992) (incorporated by reference; see § 430.3).

2.6 “ASHRAE 41.3-2014” means the test standard published jointly by the American National Standards Institute and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers titled “Standard Methods for Pressure Measurement,” Standard 41.3-2014 (incorporated by reference; see § 430.3).

2.7 “ASHRAE 41.6-2014” means the test standard published jointly by the American National Standards Institute and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers titled “Standard Method for Humidity Measurement,” Standard 41.6-2014 (incorporated by reference; see § 430.3).

2.8 “ASHRAE 41.11-2014” means the test standard published jointly by the American National Standards Institute and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers titled “Standard Methods for Power Measurement,” Standard 41.11-2014 (incorporated by reference; see § 430.3).

2.9 “Combined energy efficiency ratio” means the energy efficiency of a room air conditioner in British thermal units per watt-hour (Btu/Wh) and determined in section 5.2.2 of this appendix for single-speed room air conditioners and section 5.3.12 of this appendix for variable-speed room air conditioners.

2.10 “Cooling capacity” means the amount of cooling, in British thermal units per hour (Btu/h), provided to a conditioned space, measured under the specified conditions and determined in section 4.1 of this appendix.

2.11 “Cooling mode” means an active mode in which a room air conditioner has activated the main cooling function according to the thermostat or temperature sensor signal or switch (including remote control).

2.12 “Full compressor speed (full)” means the compressor speed at which the unit operates at full load test conditions, when using user settings with a unit thermostat setpoint of 75 °F to achieve maximum cooling capacity, according to the instructions in ANSI/ASHRAE Standard 16-2016.

2.13 “IEC 62301” means the test standard published by the International Electrotechnical Commission, titled “Household electrical appliances—Measurement of standby power,” Publication 62301 (Edition 2.0 2011-01), (incorporated by reference; see § 430.3).

2.14 “Inactive mode” means a standby mode that facilitates the activation of active mode by remote switch (including remote control) or internal sensor or which provides continuous status display.

2.15 “Intermediate compressor speed (intermediate)” means the compressor speed higher than the low compressor speed at which the measured capacity is higher than the capacity at low compressor speed by one third of the difference between Capacity4, the measured cooling capacity at test condition 4 in Table 1 of this appendix, and Capacity1, the measured cooling capacity with the full compressor speed at test condition 1 in Table 1 of this appendix, with a tolerance of plus 5 percent (designs with non-discrete speed stages) or the next highest inverter frequency step (designs with discrete speed steps), achieved by following the instructions certified by the manufacturer.

2.16 “Low compressor speed (low)” means the compressor speed at which the unit operates at low load test conditions, achieved by following the instructions certified by the manufacturer, such that Capacity4, the measured cooling capacity at test condition 4 in Table 1 of this appendix, is no less than 47 percent and no greater than 57 percent of Capacity1, the measured cooling capacity with the full compressor speed at test condition 1 in Table 1 of this appendix.

2.17 “Off mode” means a mode in which a room air conditioner is connected to a mains power source and is not providing any active or standby mode function and where the mode may persist for an indefinite time, including an indicator that only shows the user that the product is in the off position.

2.18 “Single-speed room air conditioner” means a type of room air conditioner that cannot automatically adjust the compressor speed based on detected conditions.

2.19 “Standby mode” means any product mode where the unit is connected to a mains power source and offers one or more of the following user-oriented or protective functions which may persist for an indefinite time:

(a) To facilitate the activation of other modes (including activation or deactivation of active mode) by remote switch (including remote control), internal sensor, or timer. A timer is a continuous clock function (which may or may not be associated with a display) that provides regular scheduled tasks (e.g., switching) and that operates on a continuous basis.

(b) Continuous functions, including information or status displays (including clocks) or sensor-based functions.

2.20 “Theoretical comparable single-speed room air conditioner” means a theoretical single-speed room air conditioner with the same cooling capacity and electrical power input as the variable-speed room air conditioner under test, with no cycling losses considered, at test condition 1 in Table 1 of this appendix.

2.21 “Variable-speed compressor” means a compressor that can vary its rotational speed in non-discrete stages or discrete steps from low to full.

2.22 “Variable-speed room air conditioner” means a type of room air conditioner that can automatically adjust compressor speed based on detected conditions.

3. Test Methods and General Instructions

3.1 Cooling mode. The test method for testing room air conditioners in cooling mode (“cooling mode test”) consists of applying the methods and conditions in AHAM RAC-1 Section 4, Paragraph 4.1 and for single-speed room air conditioners, Section 5, Paragraph 5.2.1.1, and for variable-speed room air conditioners, Section 5, Paragraph 5.2.1.2, except in accordance with ANSI/ASHRAE 16, including the references to ANSI/ASHRAE 41.1, ANSI/ASHRAE 41.2-1987 (RA 1992), ANSI/ASHRAE 41.3-2014, ANSI/ASHRAE 41.6-2014, and ANSI/ASHRAE 41.11-2014, all referenced therein, as defined in sections 2.3 through 2.8 of this appendix. Use the cooling capacity simultaneous indoor calorimeter and outdoor calorimeter test method in Section 7.1.a and Sections 8.1 through 8.5 of ANSI/ASHRAE 16, except as otherwise specified in this appendix. If a unit can operate on multiple operating voltages as distributed in commerce by the manufacturer, test it and rate the corresponding basic models at all nameplate operating voltages. For a variable-speed room air conditioner, test the unit following the cooling mode test a total of four times: One test at each of the test conditions listed in Table 1 of this appendix, consistent with section 4.1 of this appendix.

3.1.1 Through-the-wall installation. Install a non-louvered room air conditioner inside a compatible wall sleeve with the provided or manufacturer-required rear grille, and with only the included trim frame and other manufacturer-provided installation materials, per manufacturer instructions provided to consumers.

3.1.2 Power measurement accuracy. All instruments used for measuring electrical inputs to the test unit, reconditioning equipment, and any other equipment that operates within the calorimeter walls must be accurate to ±0.5 percent of the quantity measured.

3.1.3 Electrical supply. For cooling mode testing, test at each nameplate operating voltage, and maintain the input standard voltage within ±1 percent. Test at the rated frequency, maintained within ±1 percent.

3.1.4 Control settings. If the room air conditioner has network capabilities, all network features must be disabled throughout testing.

3.1.5 Measurement resolution. Record measurements at the resolution of the test instrumentation.

3.1.6 Temperature tolerances. Maintain each of the measured chamber dry-bulb and wet-bulb temperatures within a range of 1.0 °F.

3.2 Standby and off modes.

3.2.1 Install the room air conditioner in accordance with Section 5, Paragraph 5.2 of IEC 62301 and maintain the indoor test conditions (and outdoor test conditions where applicable) as required by Section 4, Paragraph 4.2 of IEC 62301. If testing is not conducted in a facility used for testing cooling mode performance, the test facility must comply with Section 4, Paragraph 4.2 of IEC 62301.

3.2.2 Electrical supply. For standby mode and off mode testing, maintain the electrical supply voltage and frequency according to the requirements in Section 4, Paragraph 4.3.1 of IEC 62301.

3.2.3 Supply voltage waveform. For the standby mode and off mode testing, maintain the electrical supply voltage waveform indicated in Section 4, Paragraph 4.3.2 of IEC 62301.

3.2.4 Wattmeter. The wattmeter used to measure standby mode and off mode power consumption must meet the resolution and accuracy requirements in Section 4, Paragraph 4.4 of IEC 62301.

3.2.5 Air ventilation damper. If the unit is equipped with an outdoor air ventilation damper, close this damper during standby mode and off mode testing.

4. Test Conditions and Measurements

4.1 Cooling mode.

4.1.1 Temperature conditions. Establish the test conditions described in Sections 4 and 5 of AHAM RAC-1 and in accordance with ANSI/ASHRAE 16, including the references to ANSI/ASHRAE 41.1 and ANSI/ASHRAE 41.6-2014, for cooling mode testing, with the following exceptions for variable-speed room air conditioners: Conduct the set of four cooling mode tests with the test conditions presented in Table 1 of this appendix. For test condition 1 and test condition 2, achieve the full compressor speed with user settings, as defined in section 2.12 of this appendix. For test condition 3 and test condition 4, set the required compressor speed in accordance with instructions the manufacturer provided to DOE.

4.1.2 Cooling capacity and power measurements. For single-speed units, measure the cooling mode cooling capacity (expressed in Btu/h), Capacity, and electrical power input (expressed in watts), Pcool, in accordance with Section 6, Paragraphs 6.1 and 6.2 of AHAM RAC-1, respectively, and in accordance with ANSI/ASHRAE 16, including the references to ANSI/ASHRAE 41.2-1987 (RA 1992) and ANSI/ASHRAE 41.11-2014. For variable-speed room air conditioners, measure the condition-specific cooling capacity (expressed in Btu/h), Capacitytc, and electrical power input (expressed in watts), Ptc, for each of the four cooling mode rating test conditions (tc), as required in Section 6, Paragraphs 6.1 and 6.2, respectively, of AHAM RAC-1, respectively, and in accordance with ANSI/ASHRAE 16, including the references to ANSI/ASHRAE 41.2-1987 (RA 1992) and ANSI/ASHRAE 41.11-2014.

4.2 Standby and off modes. Establish the testing conditions set forth in section 3.2 of this appendix, ensuring the unit does not enter any active mode during the test. For a unit that drops from a higher power state to a lower power state as discussed in Section 5, Paragraph 5.1, Note 1 of IEC 62301, allow sufficient time for the room air conditioner to reach the lower power state before proceeding with the test measurement. Use the sampling method test procedure specified in Section 5, Paragraph 5.3.2 of IEC 62301 for testing all standby and off modes, with the following modifications: Allow the product to stabilize for 5 to 10 minutes and use an energy use measurement period of 5 minutes.

4.2.1 If the unit has an inactive mode, as defined in section 2.14 of this appendix, measure and record the average inactive mode power, Pia, in watts.

4.2.2 If the unit has an off mode, as defined in section 2.17 of this appendix, measure and record the average off mode power, Pom, in watts.

5. Calculations

5.1 Annual energy consumption in inactive mode and off mode. Calculate the annual energy consumption in inactive mode and off mode, AECia/om, expressed in kilowatt-hours per year (kWh/year).

AECia/om = (Pia × tia + Pom × tom) Where: AECia/om = annual energy consumption in inactive mode and off mode, in kWh/year. Pia = average power in inactive mode, in watts, determined in section 4.2 of this appendix. Pom = average power in off mode, in watts, determined in section 4.2 of this appendix. tia = annual operating hours in inactive mode and multiplied by a 0.001 kWh/Wh conversion factor from watt-hours to kilowatt-hours. This value is 5.115 kWh/W if the unit has inactive mode and no off mode, 2.5575 kWh/W if the unit has both inactive and off mode, and 0 kWh/W if the unit does not have inactive mode. tom = annual operating hours in off mode and multiplied by a 0.001 kWh/Wh conversion factor from watt-hours to kilowatt-hours. This value is 5.115 kWh/W if the unit has off mode and no inactive mode, 2.5575 kWh/W if the unit has both inactive and off mode, and 0 kWh/W if the unit does not have off mode.

5.2 Combined energy efficiency ratio for single-speed room air conditioners. Calculate the combined energy efficiency ratio for single-speed room air conditioners as follows:

5.2.1 Single-speed room air conditioner annual energy consumption in cooling mode. Calculate the annual energy consumption in cooling mode for a single-speed room air conditioner, AECcool, expressed in kWh/year.

AECcool = 0.75 × Pcool Where: AECcool = single-speed room air conditioner annual energy consumption in cooling mode, in kWh/year. Pcool = single-speed room air conditioner average power in cooling mode, in watts, determined in section 4.1.2 of this appendix. 0.75 is 750 annual operating hours in cooling mode multiplied by a 0.001 kWh/Wh conversion factor from watt-hours to kilowatt-hours.

5.2.2 Single-speed room air conditioner combined energy efficiency ratio. Calculate the combined energy efficiency ratio, CEER, expressed in Btu/Wh, as follows:

Where: CEER = combined energy efficiency ratio, in Btu/Wh. Capacity = single-speed room air conditioner cooling capacity, in Btu/h, determined in section 4.1.2 of this appendix. AECcool = single-speed room air conditioner annual energy consumption in cooling mode, in kWh/year, calculated in section 5.2.1 of this appendix. AECia/om = annual energy consumption in inactive mode and off mode, in kWh/year, determined in section 5.1 of this appendix. 0.75 as defined in section 5.2.1 of this appendix.

5.3 Combined energy efficiency ratio for variable-speed room air conditioners. Calculate the combined energy efficiency ratio for variable-speed room air conditioners as follows:

5.3.1 Weighted electrical power input. Calculate the weighted electrical power input in cooling mode, Pwt, expressed in watts, as follows:

Pwt = Σtc Ptc × Wtc Where: Pwt = weighted electrical power input, in watts, in cooling mode. Ptc = electrical power input, in watts, in cooling mode for each test condition in Table 1 of this appendix. Wtc = weighting factors for each cooling mode test condition: 0.08 for test condition 1, 0.20 for test condition 2, 0.33 for test condition 3, and 0.39 for test condition 4. tc represents the cooling mode test condition: “1” for test condition 1 (95 °F condenser inlet dry-bulb temperature), “2” for test condition 2 (92 °F), “3” for test condition 3 (87 °F), and “4” for test condition 4 (82 °F).

5.3.2 Theoretical comparable single-speed room air conditioner. Calculate the cooling capacity, expressed in Btu/h, and the electrical power input, expressed in watts, for a theoretical comparable single-speed room air conditioner at all cooling mode test conditions.

Capacityss__tc = Capacity1 × (1 + (Mc × (95−Ttc))) Pss__tc = P1 × (1−(Mp × (95−Ttc))) Where: Capacityss__tc = theoretical comparable single-speed room air conditioner cooling capacity, in Btu/h, calculated for each of the cooling mode test conditions in Table 1 of this appendix. Capacity1 = variable-speed room air conditioner unit's cooling capacity, in Btu/h, determined in section 4.1.2 of this appendix for test condition 1 in Table 1 of this appendix. Pss__tc = theoretical comparable single-speed room air conditioner electrical power input, in watts, calculated for each of the cooling mode test conditions in Table 1 of this appendix. P1 = variable-speed room air conditioner unit's electrical power input, in watts, determined in section 4.1.2 of this appendix for test condition 1 in Table 1 of this appendix. Mc = adjustment factor to determine the increased capacity at lower outdoor test conditions, 0.0099 per °F. Mp = adjustment factor to determine the reduced electrical power input at lower outdoor test conditions, 0.0076 per °F. 95 is the condenser inlet dry-bulb temperature for test condition 1 in Table 1 of this appendix, 95 °F. Ttc = condenser inlet dry-bulb temperature for each of the test conditions in Table 1 of this appendix (in °F). tc as explained in section 5.3.1 of this appendix.

5.3.3 Variable-speed room air conditioner unit's annual energy consumption for cooling mode at each cooling mode test condition. Calculate the annual energy consumption for cooling mode under each test condition, AECtc, expressed in kilowatt-hours per year (kWh/year), as follows:

AECtc = 0.75 × Ptc Where: AECtc = variable-speed room air conditioner unit's annual energy consumption, in kWh/year, in cooling mode for each test condition in Table 1 of this appendix. Ptc = as defined in section 5.3.1 of this appendix. 0.75 as defined in section 5.2.1 of this appendix. tc as explained in section 5.3.1 of this appendix.

5.3.4 Variable-speed room air conditioner weighted annual energy consumption. Calculate the weighted annual energy consumption in cooling mode for a variable-speed room air conditioner, AECwt, expressed in kWh/year.

AECwt = Σtc AECtc × Wtc Where: AECwt = weighted annual energy consumption in cooling mode for a variable-speed room air conditioner, expressed in kWh/year. AECtc = variable-speed room air conditioner unit's annual energy consumption, in kWh/year, in cooling mode for each test condition in Table 1 of this appendix, determined in section 5.3.3 of this appendix. Wtc = weighting factors for each cooling mode test condition: 0.08 for test condition 1, 0.20 for test condition 2, 0.33 for test condition 3, and 0.39 for test condition 4. tc as explained in section 5.3.1 of this appendix.

5.3.5 Theoretical comparable single-speed room air conditioner annual energy consumption in cooling mode at each cooling mode test condition. Calculate the annual energy consumption in cooling mode for a theoretical comparable single-speed room air conditioner for cooling mode under each test condition, AECss__tc, expressed in kWh/year.

AECss__tc = 0.75 × Pss__tc Where: AECss__tc = theoretical comparable single-speed room air conditioner annual energy consumption, in kWh/year, in cooling mode for each test condition in Table 1 of this appendix. Pss__tc = theoretical comparable single-speed room air conditioner electrical power input, in watts, in cooling mode for each test condition in Table 1 of this appendix, determined in section 5.3.2 of this appendix. 0.75 as defined in section 5.2.1 of this appendix. tc as explained in section 5.3.1 of this appendix.

5.3.6 Variable-speed room air conditioner combined energy efficiency ratio at each cooling mode test condition. Calculate the variable-speed room air conditioner unit's combined energy efficiency ratio, CEERtc, for each test condition, expressed in Btu/Wh.

Where: CEERtc = variable-speed room air conditioner unit's combined energy efficiency ratio, in Btu/Wh, for each test condition in Table 1 of this appendix. Capacitytc = variable-speed room air conditioner unit's cooling capacity, in Btu/h, for each test condition in Table 1 of this appendix, determined in section 4.1.2 of this appendix. AECtc = variable-speed room air conditioner unit's annual energy consumption, in kWh/year, in cooling mode for each test condition in Table 1 of this appendix, determined in section 5.3.3 of this appendix. AECia/om = annual energy consumption in inactive mode and off mode, in kWh/year, determined in section 5.1 of this appendix. 0.75 as defined in section 5.2.1 of this appendix. tc as explained in section 5.3.1 of this appendix.

5.3.7 Theoretical comparable single-speed room air conditioner combined energy efficiency ratio. Calculate the combined energy efficiency ratio for a theoretical comparable single-speed room air conditioner, CEERss__tc, for each test condition, expressed in Btu/Wh.

Where: CEERss__tc = theoretical comparable single-speed room air conditioner combined energy efficiency ratio, in Btu/Wh, for each test condition in Table 1 of this appendix. Capacityss__tc = theoretical comparable single-speed room air conditioner cooling capacity, in Btu/h, for each test condition in Table 1 of this appendix, determined in section 5.3.2 of this appendix. AECss__tc = theoretical comparable single-speed room air conditioner annual energy consumption, in kWh/year, in cooling mode for each test condition in Table 1 of this appendix, determined in section 5.3.5 of this appendix. AECia/om = annual energy consumption in inactive mode and off mode, in kWh/year, determined in section 5.1 of this appendix. 0.75 as defined in section 5.2.1 of this appendix. tc as explained in section 5.3.1 of this appendix.

5.3.8 Theoretical comparable single-speed room air conditioner adjusted combined energy efficiency ratio. Calculate the adjusted combined energy efficiency ratio, for a theoretical comparable single-speed room air conditioner, CEERss__tc__adj, with cycling losses considered, for each test condition, expressed in Btu/Wh.

CEERss__tc__adj = CEERss__tc × CLFtc Where: CEERss__tc__adj = theoretical comparable single-speed room air conditioner adjusted combined energy efficiency ratio, in Btu/Wh, for each test condition in Table 1 of this appendix. CEERss__tc = theoretical comparable single-speed room air conditioner combined energy efficiency ratio, in Btu/Wh, for each test condition in Table 1 of this appendix, determined in section 5.3.7 of this appendix. CLFtc = cycling loss factor for each test condition; 1 for test condition 1, 0.956 for test condition 2, 0.883 for test condition 3, and 0.810 for test condition 4. tc as explained in section 5.3.1 of this appendix.

5.3.9 Weighted combined energy efficiency ratio. Calculate the weighted combined energy efficiency ratio for the variable-speed room air conditioner unit, CEERwt, and theoretical comparable single-speed room air conditioner, CEERss__wt, expressed in Btu/Wh.

CEERwt = Σtc CEERtc × Wtc CEERss__wt = Σtc CEERss__tc__adj × Wtc Where: CEERwt = variable-speed room air conditioner unit's weighted combined energy efficiency ratio, in Btu/Wh. CEERss__wt = theoretical comparable single-speed room air conditioner weighted combined energy efficiency ratio, in Btu/Wh. CEERtc = variable-speed room air conditioner unit's combined energy efficiency ratio, in Btu/Wh, at each test condition in Table 1 of this appendix, determined in section 5.3.6 of this appendix. CEERss__tc__adj = theoretical comparable single-speed room air conditioner adjusted combined energy efficiency ratio, in Btu/Wh, at each test condition in Table 1 of this appendix, determined in section 5.3.8 of this appendix. Wtc as defined in section 5.3.4 of this appendix. tc as explained in section 5.3.1 of this appendix.

5.3.10 Variable-speed room air conditioner performance adjustment factor. Calculate the variable-speed room air conditioner unit's performance adjustment factor, Fp.

Where: Fp = variable-speed room air conditioner unit's performance adjustment factor. CEERwt = variable-speed room air conditioner unit's weighted combined energy efficiency ratio, in Btu/Wh, determined in section 5.3.9 of this appendix. CEERss__wt = theoretical comparable single-speed room air conditioner weighted combined energy efficiency ratio, in Btu/Wh, determined in section 5.3.9 of this appendix.

5.3.11 Variable-speed room air conditioner combined energy efficiency ratio. Calculate the combined energy efficiency ratio, CEER, expressed in Btu/Wh, for variable-speed air conditioners.

CEER = CEER1 × (1 + Fp) Where: CEER = combined energy efficiency ratio, in Btu/Wh. CEER1 = variable-speed room air conditioner combined energy efficiency ratio for test condition 1 in Table 1 of this appendix, in Btu/Wh, determined in section 5.3.6 of this appendix. Fp = variable-speed room air conditioner performance adjustment factor, determined in section 5.3.10 of this appendix. [86 FR 16476, Mar. 29, 2021, as amended at 86 FR 24484, May 7, 2021; 88 FR 59791, Aug. 30, 2023]