What controls are required for heat pumps and thermostats?

Grounded in the retrieved California Green Building Standards Code (CALGreen) — click a citation to read the verbatim passage:

• CALGreen § 1-20 High relevance — show source text

  Exception: An independent perimeter heating or cooling system may serve more than one zone without individual thermostatic controls if:

  1. All zones are also served by an interior cooling system;
  2. The perimeter system is designed solely to offset envelope heat losses or gains;

  APPENDIX A6.1-20 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX A6.1 — VOLUNTARY STANDARDS FOR HEALTH FACILITIES [OSHPD 1, 2 & 4]

  3. The perimeter system has at least one thermostatic control for each building orientation of 50 feet or more; and
  4. The perimeter system is controlled by at least one thermostat located in one of the zones served by the system.

  A6.207.5.2 Criteria for zonal thermostatic controls. The individual thermostatic controls required by Section A6.207.5.1 shall meet the following requirements as applicable:

  1. Where used to control comfort heating, the thermostatic controls shall be capable of being set, locally or remotely, down to 55°F or lower.

  2. Where used to control comfort cooling, the thermostatic controls shall be capable of being set, locally or remotely, up to 85°F or higher.

  3. Where used to control both comfort heating and comfort cooling, the thermostatic controls shall meet Items 1 and 2 and shall be capable of providing a temperature range or dead band of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum. Exception: Systems with thermostats that require manual changeover between heating and cooling modes.

  4. Thermostatic controls for all unitary single zone, air conditioners, heat pumps and furnaces, shall comply with the setback thermostat requirements of Section A6.207.1.3 or, if equipped with DDC to the Zone level, with the Automatic Demand Shed Controls of Section A6.207.5.5.

  Exception: Systems serving zones that must have constant temperatures to prevent degradation of materials, a process, plants or animals.

  A6.207.5.3 Heat pump controls. All heat pumps with supplementary electric resistance heaters shall be installed with controls that comply with Section A6.207.1.2.

  A6.207.5.4 Dampers for air supply and exhaust equipment. Outdoor air supply and exhaust equipment shall be installed with dampers that automatically close upon fan shutdown.

  Exceptions:

  1. Where it can be demonstrated to the satisfaction of the enforcing agency that the equipment serves an area that must operate continuously.

  2. Gravity and other nonelectrical equipment that has readily accessible manual damper controls.

  3. At combustion air intakes and shaft vents.

  4. Where prohibited by other provisions of law.

  A6.207.5.5 Automatic demand shed controls. HVAC systems with DDC to the Zone level shall be programmed to allow centralized demand shed for noncritical zones as follows:

• CALGreen § 6.1507 High relevance — show source text

  Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
  Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
  where× = Condenser DT + LIFT
  COPadj = Kadj * COPstd|1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
  2. Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
  Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
  where× = Condenser DT + LIFT
  COPadj = Kadj * COPstd|1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
  2. Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
  Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
  where× = Condenser DT + LIFT
  COPadj = Kadj * COPstd|

  A6.207.1.2 Controls for heat pumps with supplementary electric resistance heaters. Heat pumps with supplementary electric resistance heaters shall have controls:

  A6.207.1.2.1 That prevent supplementary heater operation when the heating load can be met by the heat pump alone; and

  A6.207.1.2.2 In which the cut-on temperature for compression heating is higher than the cut-on temperature for supplementary heating and the cut-off temperature for compression heating is higher than the cut-off temperature for supplementary heating.

  Exceptions: The controls may allow supplementary heater operation during:

  1. Defrost; and
  2. Transient periods such as start-ups and following room thermostat setpoint advance, if the controls provide preferential rate control, intelligent recovery, staging, ramping or another control mechanism designed to preclude the unnecessary operation of supplementary heating.

  A6.207.1.3 Thermostats. All unitary heating and/or cooling systems including heat pumps that are not controlled by a central energy management control system (EMCS) shall have a setback thermostat.

  1. Setback capabilities. All thermostats shall have a clock mechanism that allows the building occupant to program the temperature set points for at least four periods within 24 hours. Thermostats for heat pumps shall meet the requirements of Section A6.207.1.2.

  Exception: Gravity gas wall heaters, gravity floor heaters, gravity room heaters, noncentral electric heaters, fireplaces or decorative gas appliances, wood stoves, room air conditioners and room air-conditioner heat pumps need not comply with this requirement. Additionally, room air-conditioner heat pumps need not comply with Section A6.207.1.2. Under perfor

  2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A6.1-17

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX A6.1 — VOLUNTARY STANDARDS FOR HEALTH FACILITIES [OSHPD 1, 2 & 4]

• CALGreen § 120.2 High relevance — show source text

  1. All zones are also served by an interior cooling system; and
  2. The perimeter system is designed solely to offset envelope heat losses or gains; and
  3. The perimeter system has at least one thermostatic control for each building orientation of 50 feet or more; and
  4. The perimeter system is controlled by at least one thermostat located in one of the zones served by the system.

  (b) Criteria for zonal thermostatic controls. The individual thermostatic controls required by Section 120.2(a) shall meet the following requirements as applicable:

  1. Where used to control comfort heating, the thermostatic controls shall be capable of being set, locally or remotely, down to 55°F or lower.

  2. Where used to control comfort cooling, the thermostatic controls shall be capable of being set, locally or remotely, up to 85°F or higher.

  3. Where used to control both comfort heating and comfort cooling, the thermostatic controls shall meet Items 1 and 2 and shall be capable of providing a temperature range or dead band of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum.

  72 2025 CALIFORNIA ENERGY CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  NONRESIDENTIAL, HOTEL/MOTEL OCCUPANCIES, AND COVERED PROCESSES—MANDATORY REQUIREMENTS

  Exception 1 to Section 120.2(b)3: Systems with thermostats that require manual changeover between heating and cooling modes. Exception 2 to Section 120.2(b)3: Systems serving healthcare facilities. 4. Thermostatic controls for all single zone, air conditioners and heat pumps shall comply with the requirements of Sections 110.2(c) and 110.12(a) and, if equipped with DDC to the Zone level, with the Automatic Demand Shed Controls of Section 110.12(b). Exception 1 to Section 120.2(b)4: Systems serving non-covered process loads that must have constant temperatures to prevent degradation of materials, a process, plants or animals. Exception 2 to Section 120.2(b)4: Package terminal air conditioners, package terminal heat pumps, room air conditioners and room air conditioner heat pumps. Exception 3 to Section 120.2(b)4: Systems serving healthcare facilities.

  (c) Hotel/motel guest room thermostats.

  1. Hotel/motel guest room thermostats shall: A. Have numeric temperature setpoints in °F and °C; and B. Have setpoint stops, which are accessible only to authorized personnel, such that guest room occupants cannot adjust the setpoint more than ±5°F (±3°C); and C. Meet the requirements of Section 110.2(c).

  Exception to Section 120.2(c)1: Thermostats that are integrated into the room heating and cooling equipment.

  (d) Heat pump controls. All heat pumps with supplementary electric resistance heaters shall be installed with controls that comply with Section 110.2(b).

  (e) Shut-off and reset controls for space-conditioning systems. Each space-conditioning system shall be installed with controls that comply with the following:

  1. The control shall be capable of automatically shutting off the system during periods of nonuse and shall have: A. An automatic time switch control device complying with Section 110.9 with an accessible manual override that allows operation of the system for up to 4 hours; or

  B. An occupancy sensor; or C. A 4-hour timer that can be manually operated.

• CALGreen § 160.3 High relevance — show source text

  (a) Controls. Space-conditioning systems serving dwelling units and common use areas in multifamily buildings shall comply with applicable requirements of Section 160.3(a)1 or 160.3(a)2.

  1. Dwelling unit thermostats. All heating or cooling systems, including heat pumps, not controlled by a central energy management control system (EMCS) shall have a setback thermostat, as specified in Section 110.2(c).
  2. Common use area controls . Heating or cooling systems serving common use areas of multifamily buildings shall comply with application requirements of Sections 160.3(a)2A through 160.3(a)2J. Exception to Section 160.3(a)2: Heating or cooling systems exclusively serving dwelling units and common use areas providing shared provisions for living, eating, cooking or sanitation to dwelling units that would otherwise lack these provisions may instead comply with Section 160.3(a)1. A. Thermostatic controls for each zone. The supply of heating and cooling energy to each space-conditioning zone shall be controlled by an individual thermostatic control that responds to temperature within the zone and that meets the applicable requirements of Section 160.3(a)2B. An energy management control system (EMCS) may be installed to comply with the requirements of one or more thermostatic controls if it complies with all applicable requirements for each thermostatic control. Exception to Section 160.3(a)2A: An independent perimeter heating or cooling system may serve more than one zone without individual thermostatic controls if:

  i. All zones are also served by an interior cooling system; and ii. The perimeter system is designed solely to offset envelope heat losses or gains; and iii. The perimeter system has at least one thermostatic control for each building orientation of 50 feet or more; and iv. The perimeter system is controlled by at least one thermostat located in one of the zones served by the system. B. Criteria for zonal thermostatic controls. The individual thermostatic controls required by Section 160.3(a)2A shall meet the following requirements as applicable: i. Where used to control comfort heating, the thermostatic controls shall be capable of being set, locally or remotely, down to 55°F or lower. ii. Where used to control comfort cooling, the thermostatic controls shall be capable of being set, locally or remotely, up to 85°F or higher. iii. Where used to control both comfort heating and comfort cooling, the thermostatic controls shall meet Items i and ii and shall be capable of providing a temperature range or deadband of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum. Exception to Section 160.3(a)2Biii: Systems with thermostats that require manual changeover between heating and cooling modes. iv. Thermostatic controls for all single zone air conditioners and heat pumps shall comply with the requirements of Sections 110.2(c) and 110.12(a) and, if equipped with DDC to the zone level, with the automatic demand shed controls of Section 110.12(b). Exception to Section 160.3(a)2Biv: Package terminal air conditioners, package terminal heat pumps, room air conditioners and room air-conditioner heat pumps. C. Heat pump controls. All heat pumps with supplementary electric resistance heaters shall be installed with controls that comply with Section 110.2(b).

• CALGreen § 120.2 High relevance — show source text

  Exception 1 to Section 120.2(b)4: Systems serving non-covered process loads that must have constant temperatures to prevent degradation of materials, a process, plants or animals. Exception 2 to Section 120.2(b)4: Package terminal air conditioners, package terminal heat pumps, room air conditioners and room air conditioner heat pumps. Exception 3 to Section 120.2(b)4: Systems serving healthcare facilities.

  (c) Hotel/motel guest room thermostats.

  1. Hotel/motel guest room thermostats shall: A. Have numeric temperature setpoints in °F and °C; and B. Have setpoint stops, which are accessible only to authorized personnel, such that guest room occupants cannot adjust the setpoint more than ±5°F (±3°C); and C. Meet the requirements of Section 110.2(c).

  Exception to Section 120.2(c)1: Thermostats that are integrated into the room heating and cooling equipment.

  (d) Heat pump controls. All heat pumps with supplementary electric resistance heaters shall be installed with controls that comply with Section 110.2(b).

  (e) Shut-off and reset controls for space-conditioning systems. Each space-conditioning system shall be installed with controls that comply with the following:

  1. The control shall be capable of automatically shutting off the system during periods of nonuse and shall have: A. An automatic time switch control device complying with Section 110.9 with an accessible manual override that allows operation of the system for up to 4 hours; or

  B. An occupancy sensor; or C. A 4-hour timer that can be manually operated. Exception to Section 120.2(e)1: Mechanical systems serving retail stores and associated malls, restaurants, grocery stores, churches and theaters equipped with 7-day programmable timers. 2. The control shall automatically restart and temporarily operate the system as required to maintain: A. A setback heating thermostat setpoint if the system provides mechanical heating; and Exception to Section 120.2(e)2A: Thermostat setback controls are not required in nonresidential buildings in areas where the Winter Median of Extremes outdoor air temperature determined in accordance with Section 140.4(b)3 is greater than 32°F. B. A setup cooling thermostat setpoint if the system provides mechanical cooling. Exception to Section 120.2(e)2B: Thermostat setup controls are not required in nonresidential buildings in areas where the Summer Design Dry Bulb 0.5 percent temperature determined in accordance with Section 140.4(b)3 is less than 100°F.

  3. Occupant sensing zone controls. Where the system providing space conditioning also provides the ventilation required by Section 120.1 and includes occupant sensor ventilation control as specified in Section 120.1(d)5, the occupant sensing zone controls shall additionally comply with the following: A. In 5 minutes or less after entering occupied-standby mode as described in Section 120.1(d). i. Automatically set up the operating cooling temperature set point by 2°F or more and set back the operating heating temperature set point by 2°F or more; or ii. For multiple zone systems with Direct Digital Controls (DDC) to the zone level, setup the operating cooling temperature setpoint by 0.5°F or more and setback the operating heating temperature setpoint by 0.5°F or

  more.

• CALGreen § 207.1.3 High relevance — show source text

  3. Where used to control both comfort heating and comfort cooling, the thermostatic controls shall meet Items 1 and 2 and shall be capable of providing a temperature range or dead band of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum. Exception: Systems with thermostats that require manual changeover between heating and cooling modes.
  4. Thermostatic controls for all unitary single zone, air conditioners, heat pumps and furnaces, shall comply with the setback thermostat requirements of Section A6.207.1.3 or, if equipped with DDC to the Zone level, with the Automatic Demand Shed Controls of Section A6.207.5.5.

  Exception: Systems serving zones that must have constant temperatures to prevent degradation of materials, a process, plants or animals.

  A6.207.5.3 Heat pump controls. All heat pumps with supplementary electric resistance heaters shall be installed with controls that comply with Section A6.207.1.2.

  A6.207.5.4 Dampers for air supply and exhaust equipment. Outdoor air supply and exhaust equipment shall be installed with dampers that automatically close upon fan shutdown.

  Exceptions:

  1. Where it can be demonstrated to the satisfaction of the enforcing agency that the equipment serves an area that must operate continuously.

  2. Gravity and other nonelectrical equipment that has readily accessible manual damper controls.

  3. At combustion air intakes and shaft vents.

  4. Where prohibited by other provisions of law.

  A6.207.5.5 Automatic demand shed controls. HVAC systems with DDC to the Zone level shall be programmed to allow centralized demand shed for noncritical zones as follows:

  1. The controls shall have a capability to remotely setup the operating cooling temperature set points by 4 degrees or more in all noncritical zones on signal from a centralized contact or software point within an Energy Management Control System (EMCS).
  2. The controls shall remotely set down the operating heating temperature set points by 4 degrees or more in all noncritical zones on signal from a centralized contact or software point within an EMCS.
  3. The controls shall have capabilities to remotely reset the temperatures in all noncritical zones to original operating levels on signal from a centralized contact or software point within an EMCS.
  4. The controls shall be programmed to provide an adjustable rate of change for the temperature setup and reset.

  A6.207.6 Pipe insulation. The piping for all space- conditioning and service water-heating systems with fluid temperatures listed in Table A6.207.6-A shall have the amount of insulation specified in Subsection A6.207.6.1 or A6.207.6.2. Insulation conductivity shall be determined in accordance with ASTM C335 at the mean temperature listed in Table A6.207.6-A and shall be rounded to the nearest 1 / 100 Btu-inch per hour per square foot per °F.

  Insulation shall be protected from damage, including that due to sunlight, moisture, equipment maintenance and wind, including but not limited to, the following:

  Insulation exposed to weather shall be suitable for outdoor service, e.g., protected by aluminum, sheet metal, painted canvas or plastic cover. Cellular foam insulation shall be protected as above or painted with a coating that is water retardant and provides shielding from solar radiation that can cause degradation of the material.

  Insulation covering chilled water piping and refrigerant suction piping located outside the conditioned space shall include a vapor retardant located outside the insulation (unless the insulation is inherently vapor retardant), all penetrations and joints of which shall be sealed.

• CALGreen § 207.1.2.2 High relevance — show source text

  A6.207.1.2.2 In which the cut-on temperature for compression heating is higher than the cut-on temperature for supplementary heating and the cut-off temperature for compression heating is higher than the cut-off temperature for supplementary heating.

  Exceptions: The controls may allow supplementary heater operation during:

  1. Defrost; and
  2. Transient periods such as start-ups and following room thermostat setpoint advance, if the controls provide preferential rate control, intelligent recovery, staging, ramping or another control mechanism designed to preclude the unnecessary operation of supplementary heating.

  A6.207.1.3 Thermostats. All unitary heating and/or cooling systems including heat pumps that are not controlled by a central energy management control system (EMCS) shall have a setback thermostat.

  1. Setback capabilities. All thermostats shall have a clock mechanism that allows the building occupant to program the temperature set points for at least four periods within 24 hours. Thermostats for heat pumps shall meet the requirements of Section A6.207.1.2.

  Exception: Gravity gas wall heaters, gravity floor heaters, gravity room heaters, noncentral electric heaters, fireplaces or decorative gas appliances, wood stoves, room air conditioners and room air-conditioner heat pumps need not comply with this requirement. Additionally, room air-conditioner heat pumps need not comply with Section A6.207.1.2. Under perfor

  2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A6.1-17

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX A6.1 — VOLUNTARY STANDARDS FOR HEALTH FACILITIES [OSHPD 1, 2 & 4]

  mance method of compliance, the resulting increase in energy use due to elimination of the setback thermostat shall be factored into the compliance analysis in accordance with a method prescribed by the Executive Director.

  A6.207.1.4 Gas- and oil-fired furnace standby loss controls. Gas-fired and oil-fired forced air furnaces with input ratings ≥ 225,000 Btu/h shall also have an intermittent ignition or interrupted device (IID) and have either power venting or a flue damper. A vent damper is an acceptable alternative to a flue damper for furnaces where combustion air is drawn from the conditioned space. All furnaces with input ratings ≥ 225,000 Btu/h, including electric furnaces, that are not located within the conditioned space shall have jacket losses not exceeding 0.75 percent of the input rating.

  A6.207.2 Space conditioning systems. A building complies with this section by being designed with and having constructed and installed a space-conditioning system that meets the requirements of Subsections A6.207.2.1 through A6.207.2.6.

  A6.207.2.1 Supply-air temperature reset controls. Mechanical space-conditioning systems supplying heated or cooled air to multiple zones shall include controls that automatically reset supply-air temperatures:

  1. In response to representative building loads or to outdoor air temperature; and
  2. By at least 25 percent of the difference between the design supply-air temperature and the design room air temperature.

  Air distribution systems serving zones that are likely to have constant loads, such as interior zones, shall be designed for the air flows resulting from the fully reset supply-air temperature.

• CALGreen § 150.0 High relevance — show source text

  6. Defrost.

  A. If a heat pump is equipped with an installer adjustable defrost delay timer, the delay timer shall be set to greater than or equal to 90 minutes. B. The installer shall certify on the Certificate of Installation (CF2R) that the control configuration has been tested in accordance with the testing procedure in the CF2R.

  Exception 1 to Section 150.0(h)6. Dwelling units in Climate Zones 6 and 7.

  Exception 2 to Section 150.0(h)6. Dwelling units with a conditioned floor area of 500 square feet or less in Climate Zones 3, 5 through 10, and 15. 7. Supplementary heating control configuration. Heat pumps with supplementary heat, including, but not limited to, electric resistance heaters or gas furnace supplementary heating, shall comply with the following requirements: A. Lock out supplementary heating above an outdoor air temperature of not greater than 35°F. There are additional thermostat requirements in section 150.0(i)2. B. The installer shall certify on the Certificate of Installation that the control configuration has been tested in accordance with the testing procedure found in the CF2R. C. The controls may allow supplementary heater operation above 35°F only during defrost or when the user selects emergency operation.

  Exception 1 to Section 150.0(h)7: For buildings with a conditioned floor area less than 500 square feet, and for buildings of any size in Climate Zones 7 and 15, heat pumps with supplementary heaters shall have controls that meet Item i or ii:

  i. Option A:

  1. That prevent supplementary heater operation when the heating load can be met by the heat pump alone; and

  2. In which the cut-on temperature for heat pump heating is higher than the cut-on temperature for supplementary heating, and the cut-off temperature for heat pump heating is higher than the cut-off temperature for supplementary heating. ii. Option B: The controls may allow supplementary heater operation during defrost mode and transient periods, such as start-ups and following a room thermostat setpoint advance, if the controls prevent the unnecessary operation of supplementary heating.

  Exception 2 to Section 150.0(h)7: Room air-conditioner heat pumps. 8. Sizing of electric resistance supplementary heat. Where heat pumps have electric resistance heat, the capacity of electric resistance heat shall not exceed the heat pump nominal cooling capacity (at 95°F ambient conditions) multiplied by 2.7 kW per ton, rounded up to the closest kW. 9. Capacity variation with third-party thermostats. Variable or multi-speed systems shall comply with the following requirements: A. The space conditioning system and thermostat together shall be capable of responding to heating and cooling loads by modulating system compressor speed, and meet thermostat requirements in Section 150.0(i)2. B. The installer shall certify on the Certificate of Installation that the control configuration has been tested in accordance with the testing procedure found in the CF2R.

  (i) Thermostats.

  1. Setback thermostats. All heating or cooling systems, including heat pumps, not controlled by a central energy management control system (EMCS) shall have a setback thermostat, as specified in Section 110.2(c).
  2. Thermostats that are applied to heat pumps with supplemental heating. In addition to the requirements in Section 150.0(i)1, thermostats controlling heat pumps with electric resistance supplementary heat or gas furnace supplementary heat shall comply with the following requirements: A. The thermostat shall receive outdoor air temperature from an outdoor air temperature sensor or from an internet weather service.
• CALGreen § 110.2 High relevance — show source text

  ranges:

   - Minimum Leaving Evaporator Fluid Temperature: 36°F
  
  - Maximum Leaving Condenser Fluid Temperature: 115°F
  
    - LIFT ≥ 20°F and ≤ 80°F
  

  Centrifugal chillers designed to operate outside of these ranges are not covered by this exception.

  Exception 2 to Section 110.2(a): Positive displacement (air-cooled and water-cooled) chillers with a leaving evaporator fluid temperature higher than 32°F shall show compliance with Table 110.2-D when tested or certified with water at standard rating conditions, per the referenced test procedure.

  Exception 3 to Section 110.2(a): Equipment primarily serving refrigerated warehouses or commercial refrigeration.

  (b) Controls for heat pumps with supplementary heaters.

  Control requirements for heat pumps with supplementary heaters in single-family residential buildings are specified in Section 150.0(h)7 and Section 150.0(i)2. Heat pumps with supplementary heaters in nonresidential and multifamily buildings shall have controls:

  1. That prevent supplementary heater operation when the heating load can be met by the heat pump alone; and
  2. In which the cut-on temperature for heat pump heating is higher than the cut-on temperature for supplementary heating, and the cut-off temperature for heat pump heating is higher than the cut-off temperature for supplementary heating. Exception 1 to Section 110.2(b): The controls may allow supplementary heater operation during: A. Defrost; and

  B. Transient periods such as start-ups and following room thermostat setpoint advance, if the controls provide preferential rate control, intelligent recovery, staging, ramping or another control mechanism designed to preclude the unnecessary operation of supplementary heating.

  Exception 2 to Section 110.2(b): Room air-conditioner heat pumps.

  40 2025 CALIFORNIA ENERGY CODE

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  ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS

  (c) Thermostats. All heating or cooling systems not controlled by a central energy management control system (EMCS) shall have a setback thermostat.

  1. Setback capabilities. All thermostats shall have a clock mechanism that allows the building occupant to program the temperature setpoints for at least four periods within 24 hours. Thermostats for heat pumps shall meet the requirements of Section 110.2(b).

  Exception to Section 110.2(c): Gravity gas wall heaters, gravity floor heaters, gravity room heaters, noncentral electric heaters, fireplaces or decorative gas appliances, wood stoves, room air conditioners and room air-conditioner heat pumps.

  (d) Gas-fired and oil-fired furnace standby loss controls. Gas-fired and oil-fired forced-air furnaces with input ratings ≥ 225,000 Btu/hr shall also have an intermittent ignition or interrupted device (IID), and have either power venting or a flue damper. A vent damper is an acceptable alternative to a flue damper for furnaces where combustion air is drawn from the conditioned space. All furnaces with input ratings ≥ 225,000 Btu/hr, including electric furnaces, that are not located within the conditioned space shall have jacket losses not exceeding 0.75 percent of the input rating.

  (e) Open and closed-circuit cooling towers. All open and closed-circuit cooling tower installations shall comply with the following:

  1. Be equipped with conductivity controls that maximize cycles of concentration based on local water quality conditions.
• CALGreen § 150.0 High relevance — show source text

  Exception 2 to Section 150.0(h)7: Room air-conditioner heat pumps. 8. Sizing of electric resistance supplementary heat. Where heat pumps have electric resistance heat, the capacity of electric resistance heat shall not exceed the heat pump nominal cooling capacity (at 95°F ambient conditions) multiplied by 2.7 kW per ton, rounded up to the closest kW. 9. Capacity variation with third-party thermostats. Variable or multi-speed systems shall comply with the following requirements: A. The space conditioning system and thermostat together shall be capable of responding to heating and cooling loads by modulating system compressor speed, and meet thermostat requirements in Section 150.0(i)2. B. The installer shall certify on the Certificate of Installation that the control configuration has been tested in accordance with the testing procedure found in the CF2R.

  (i) Thermostats.

  1. Setback thermostats. All heating or cooling systems, including heat pumps, not controlled by a central energy management control system (EMCS) shall have a setback thermostat, as specified in Section 110.2(c).
  2. Thermostats that are applied to heat pumps with supplemental heating. In addition to the requirements in Section 150.0(i)1, thermostats controlling heat pumps with electric resistance supplementary heat or gas furnace supplementary heat shall comply with the following requirements: A. The thermostat shall receive outdoor air temperature from an outdoor air temperature sensor or from an internet weather service.

  B. The thermostat shall display the outdoor air temperature. C. As described in Section 150.0(h)7, the thermostat and heat pump shall lock out supplementary heat when the outdoor air temperature is above 35°F. D. The thermostat shall have an indicator to notify when supplementary heat or emergency heat is in use. E. During defrost or when the user selects emergency heating, supplementary heat operation is permitted above 35°F. F. The installer shall certify on the Certificate of Installation that the system has been tested in accordance with the testing procedure found in the CF2R.

  Exception to Section 150.0(i)2A, B, and C: Where supplementary heat is locked out above 35°F by another control device in accordance with Section 150.0(h)7.

  2025 CALIFORNIA ENERGY CODE 161

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  SINGLE-FAMILY RESIDENTIAL BUILDINGS— MANDATORY FEATURES AND DEVICES

  Exception 1 to Section 150.0(i)2: Systems compliant with Exception 1 to Section 150.0(h)7.

  Exception 2 to Section 150.0(i)2: Room air-conditioner heat pumps.

  (j) Insulation for piping and tanks.

  1. Water piping, solar water-heating system piping, and space-conditioning system line insulation thickness and conductivity. Piping shall be insulated as follows: A. All domestic hot water piping shall be insulated as specified in Section 609.12 of the California Plumbing Code . B. Piping for space-conditioning systems, solar water-heating system collector loop, and distribution piping for steam and hydronic heating system shall meet the requirements of Section 120.3(a). Exception 1 to Section 150.0(j)1: Factory-installed piping within space-conditioning equipment certified under Section 110.1 or 110.2.

  Exception 2 to Section 150.0(j)1: Piping that penetrates framing members shall not be required to have pipe insulation for the distance of the framing penetration.

• CALGreen § 503.7.1 High relevance — show source text

  ** Heat pumps equipped with internal electric resistance heaters shall have controls that prevent supplemental heater operation where the heating load is capable of being met by the heat pump alone during both steady-state operation and setback recovery. Supplemental heater operation shall be permitted during outdoor coil defrost cycles. Exception: Heat pumps whose minimum efficiency is regulated by U.S. National Appliance Energy Conservation Act (NAECA) and whose ratings are in accordance with the requirements shown in Table E 503.7.1(2) and includes the use of an internal electric resistance heating. [ASHRAE 90.1:6.4.3.5] E 503.4.6.7 Humidification and Dehumidifica- tion Control. Humidification and dehumidification

  control shall be in accordance with Section E 503.4.6.7.1 through Section E 503.4.6.7.3. E 503.4.6.7.1 Dehumidification. Humidistatic controls shall not use mechanical cooling to reduce the humidity below the lower of a dew point of 55°F (12.8°C) or relative humidity of 60 percent in the coldest zone served by the system. Exceptions: (1) Lower humidity shall be permitted when operating mechanical cooling for temperature control.

  (2) Systems serving zones where specific humidity levels are required, such as museums and hospitals, and approved by the Authority Having Jurisdiction or required by accreditation standards, and where humidistatic controls are capable of and configured to maintain a dead band of at least 10 percent relative humidity where no active humidification or dehumidification takes place.

  (3) Systems serving zones where humidity levels are required to be maintained with precision of not more than ±5 percent relative humidity to comply with applicable codes or accreditation standards or as approved by the Authority Having Jurisdiction.

  [ASHRAE 90.1:6.4.3.6.1]

  E 503.4.6.7.2 Humidification. Humidistatic controls shall not use fossil fuel or electricity to produce relative humidity above 30 percent in the warmest zone served by the system.

  Exceptions:

  (1) Systems serving zones where specific humidity levels are required, such as museums and hospitals, and approved by the Authority Having Jurisdiction or required by accreditation standards, and where humidistatic controls are capable of and configured to maintain a dead band of at least 10 percent relative humidity where no active humidification or dehumidification takes place.

  TABLE E 503.4.6.4.2 MAXIMUM DAMPER LEAKAGE [1, 2]

  (cubic foot per minute per square foot) at 1.0 inch water gauge

  [ASHRAE 90.1: TABLE 6.4.3.4.3]

• CALGreen § 207.1.1 High relevance — show source text

  **
  A6.207.1.1 Efficiency.
  A6.207.1.2 Controls for heat pumps with supplementary electric resistance heaters.
  A6.207.1.3 Thermostats.
  A6.207.1.4 Gas-and oil-fired furnace standby loss controls.||
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  || |A6.207.2 Space conditioning systems.
  A6.207.2.1 Supply air temperature reset controls.
  A6.207.2.2 Electric resistance heating.
  A6.207.2.3 Heat rejection systems.
  A6.207.2.4 Hydronic system measures.
  A6.207.2.5 Air distribution system duct leakage sealing.
  A6.207.2.6 Variable air volume control for single zone systems.||
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  || |A6.207.3 Service water-heating systems and equipment.
  A6.207.3.1 Certification by manufacturers.
  A6.207.3.2 Efficiency.
  A6.207.3.3 Installation.||
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  || |A6.207.4 Natural gas central furnaces, cooking equipment and pool and spa heaters.
  Pilot lights prohibited.||||| |A6.207.5 Controls for space-conditioning systems.
  A6.207.5.1 Thermostatic controls for each zone.
  A6.207.5.2 Criteria for zonal thermostatic controls.
  A6.207.5.3 Heat pump controls.
  A6.207.5.4 Dampers for air supply and exhaust equipment.
  A6.207.5.5 Automatic demand shed controls.||
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  || |A6.207.6 Pipe insulation.||||| |SECTION A6.209 Lighting||||| |A6.209.1 Lighting control devices, ballasts and luminaires.
  A6.209.1.1 All devices: Instructions and calibration.
  A6.209.1.2 Indicator lights.
  **A6.209.1.3 Automatic time switch control devices.