CRC · California Residential Code
CALGreen residential requirements for altered pool/spa heating
If you alter pool or spa heating in a residential multifamily building under CALGreen Appendix A4, you must pick a qualifying option — for example a **solar system sized to at least 65%** of the pool surface or a **heat‑pump pool heater** sized per the referenced method — or meet one of the other listed options in **§ A4.204.1.2**. For single‑family AC alterations **§ A4.204.1.1** requires either making a heat pump the primary heating source or meeting specific air‑conditioner performance and testing requirements (duct R‑8, ≤5% leakage, ≥400 CFM/ton return airflow, ≤0.35 W/CFM fan efficacy, attic/ceiling insulation and air sealing). Confirm local adoption of Appendix A4 before assuming these rules are mandatory and submit required calculations and field‑test documentation when claiming exceptions.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
When you alter a pool or spa heating system in an existing residential building, the altered system must meet one of several prescribed sizing/energy options — for example a solar pool heating system sized to at least 65% of the pool surface or a heat pump pool heater sized per the referenced method. These requirements are contained in § A4.204.1.2 of Appendix A4 (residential voluntary measures) and are quoted and summarized from that section.
If you are altering a space‑conditioning system in a single‑family dwelling (mechanical cooling), the alteration must either make a heat pump the primary heating source sized per Title 24 system selection rules, or meet a set of performance and installation requirements for a replacement air conditioner (duct insulation, leakage, airflow, fan efficacy, attic insulation, ceiling air‑sealing) as set out in § A4.204.1.1.
The single most important rule: if you alter pool/spa heating in a residential multifamily building you must choose a heating option that demonstrably uses no more energy than the prescribed solar/heat‑pump/renewable combinations in § A4.204.1.2.
Requirements in detail
Which projects are covered
- Alterations to existing residential buildings: the provisions cited are in Appendix A4 (residential voluntary measures) and apply where the local jurisdiction has adopted these Appendix A4 measures as mandatory. Confirm local adoption before assuming mandatory applicability.
- § A4.204.1.1 covers altered space‑conditioning systems serving existing single‑family dwelling units when an air conditioner is installed or replaced.
- § A4.204.1.2 covers altered pool and/or spa heating for existing multifamily buildings.
Key defined terms (first appearance bolded)
- Heat pump (as primary heating source) — referenced in § A4.204.1.1 and § A4.204.1.2.
- Air conditioner — replacement/installation requirements are listed in § A4.204.1.1.
- Solar pool heating system collector area — sizing metric used in § A4.204.1.2 (see table below).
Decision‑relevant dimensions and values
| Decision factor | Requirement / Metric | Value / Threshold | Code Reference |
|---|---|---|---|
| Heat pump as primary heating (single‑family space conditioning) | Must be primary heating source and sized per system selection requirements | See Title 24, Part 6 § 150.0(h)5 (system selection) | § A4.204.1.1 a. |
| Air conditioner — duct insulation (replacement option) | Ducts in unconditioned space | R‑8 | § A4.204.1.1 b.i. |
| Air conditioner — duct leakage | System measured leakage ≤ ? of air handler flow | ≤ 5% of system air handler airflow (verified by field testing) | § A4.204.1.1 b.ii. |
| Air conditioner — return airflow | Return grille airflow in every control mode | ≥ 400 CFM per ton (nominal) | § A4.204.1.1 b.iii. |
| Air conditioner — fan efficacy | Air‑handler fan efficacy | ≤ 0.35 W/CFM | § A4.204.1.1 b.iii. |
| Attic insulation (vented attic) | U‑factor or insulation R‑value | U = 0.020 (or R‑49 at ceiling level) | § A4.204.1.1 b.v. cite |
| Ceiling air sealing | Air seal accessible areas between attic and conditioned space | Must comply with Title 24, Part 6 § 150.2(b)1Jii | § A4.204.1.1 b.vi. |
| Solar collector area (multifamily pools/spas) | Solar collector surface area equivalent to a percentage of pool/spa surface area | ≥ 65% of pool/spa surface area | § A4.204.1.2 Item 1. |
| Heat pump pool heater (option) | Heat pump pool heater as primary heating system; sizing per JA16.3; controls per Title 24 | See Reference Joint Appendix JA16.3; control per § 110.4(d) (Title 24, Part 6) | § A4.204.1.2 Item 2. |
| On‑site renewables option | Derive % of annual heating energy from on‑site renewables/recovered energy | ≥ 60% annual heating energy from on‑site sources | § A4.204.1.2 Item 3. |
| Combinations / equivalency | Solar + heat pump combination allowed (no additional supplementary heater) | Combination permitted per Item 4; or Energy Commission determination per Item 5 | § A4.204.1.2 Items 4 & 5. |
(Notes: JA16.3 and § 110.4(d) are Title 24 references incorporated by cross‑reference within § A4.204.1.2; the Appendix text explicitly points to them for sizing and control requirements.)
Controls, verification and documentation
- Heat pump pool heaters used as the primary heating must meet the referenced sizing method (JA16.3) and controls requirements stated in the code text; the supplementary heater is allowed but controls must prevent it from running when the heat pump alone meets the load (see related Title 24 control rules).
- For altered single‑family space‑conditioning systems, multiple performance items (duct leakage verification, airflow and fan efficacy testing, refrigerant charge verification) require field verification and diagnostic testing following the referenced Title 24 procedures. § A4.204.1.1 b.ii–b.iv requires those tests.
Exceptions & special cases
- Electrical panel capacity exception (A4.204.1.1): If the existing main electrical service panel cannot supply the electrical capacity of a heat pump but can supply a replacement air conditioner (per California Electrical Code Article 220.83 or 220.87), documentation of load calculations must be submitted and the air‑conditioner option is permitted. Exception 1 to § A4.204.1.1.
- Sizing delta exception (A4.204.1.1): If meeting the heat pump sizing requirements would require a capacity at least 12,000 Btu/h greater than the air‑conditioner required for the cooling load, the air‑conditioner option may be used after submittal of load calculations. Exception 2 to § A4.204.1.1.
- Pool/spa exceptions (A4.204.1.2) include:
- Portable electric spas that comply with the Appliance Efficiency Regulations (20 CCR § 1605.3(g)(7)). Exception 1 to § A4.204.1.2.
- Pools/spas heated solely by solar without a supplementary heater. Exception 2 to § A4.204.1.2.
- Inadequate Solar Access Roof Area (SARA) for solar collectors per the Energy Code provisions. Exception 3 to § A4.204.1.2.
- Systems used exclusively for permanent spa applications in existing buildings with gas availability. Exception 4 to § A4.204.1.2.
If an exception is claimed, the section text requires appropriate documentation (e.g., electrical load calculations, SARA determination) to be submitted to the enforcement agency.
Common mistakes
- Assuming Appendix A4 is automatically mandatory. Appendix A4 is a set of voluntary residential measures unless the local jurisdiction formally adopts them. Always confirm local adoption.
- Omitting the required field verification/testing for duct leakage, airflow, fan efficacy and refrigerant charge when using the air‑conditioner option under § A4.204.1.1. These are not optional and must follow the referenced Title 24 verification procedures.
- Mis‑sizing solar collectors by using the single‑family 60% figure from Title 24 rather than the multifamily 65% figure in § A4.204.1.2 (this Appendix item is specific to multifamily in A4.204.1.2). Confirm which section applies to your project.
- Failing to submit required load calculations or electrical service documentation when relying on an exception (for example the 12,000 Btu/h exception or electrical panel capacity exception).
- Treating a heat‑pump pool heater’s supplementary source as allowed to run without proper controls — Title 24 control rules for heat pump + supplementary heaters require the supplementary heater to be disabled when the heat pump can meet the load.
Worked example — concrete scenario
Scenario A — Multifamily pool alteration
- Existing multifamily pool surface area = 400 ft².
- Option A: Install a solar pool heating system sized per § A4.204.1.2 Item 1.
- Required collector area = 65% × 400 ft² = 260 ft² of solar collector surface.
- If site cannot provide 260 ft² of usable SARA, you must either select another qualifying option (heat pump per JA16.3, on‑site renewables, combination), or document the SARA limitation under Exception 3 to § A4.204.1.2.
- Option B: Install a heat pump pool heater sized per JA16.3 and controls per § 110.4(d). The project must provide the JA16.3 sizing calculations and demonstrate control strategy to prevent the supplementary heater from operating when the heat pump meets the load. § A4.204.1.2 Item 2.
Scenario B — Single‑family AC replacement (mechanical cooling)
- Replace a 3‑ton air conditioner (nominal).
- If choosing the air‑conditioner option under § A4.204.1.1 b.:
- Minimum return airflow required = 400 CFM/ton × 3 ton = 1,200 CFM through return grilles in every control mode. § A4.204.1.1 b.iii.
- Maximum air‑handler fan power allowed = 0.35 W/CFM × 1,200 CFM = 420 W. § A4.204.1.1 b.iii.
- Duct insulation for ducts in unconditioned space must be R‑8. § A4.204.1.1 b.i.
- Duct system measured leakage must be ≤ 5% of system airflow and confirmed via field testing. § A4.204.1.1 b.ii.
Related provisions
- § A4.204.1.1 — Altered space‑conditioning system serving existing single‑family dwelling units (mechanical cooling).
- § A4.204.1.2 — Altered pool and/or spa heating for existing multifamily buildings (the controlling pool/spa sizing options and exceptions).
- Appendix A4 (general) — Appendix A4 is the residential voluntary measures where these sections live (confirm local adoption). § A4.201.1 describes scope and voluntary nature.
- Title 24, Part 6 cross‑references used by the Appendix: system selection and sizing rules at § 150.0(h)5, installation/verification references § 150.2(b) and the Reference Residential Appendix testing procedures (RA3.*) — these are invoked by § A4.204.1.1.
- Title 24 (Energy Code) § 110.4 — mandatory pool & spa equipment installation and control standards referenced by § A4.204.1.2 Item 2 and other pool heater control requirements.
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 150.2 High relevance — show source text
Air seal all accessible areas of the ceiling plane between the attic and the conditioned space in accordance with the requirements in Title 24, Part 6 Section 150.2(b)1Jii.
Exception 1 to Section A4.204.1.1: Where the capacity of the existing main electrical service panel is insufficient to supply the electrical capacity of a heat pump and where the existing main electrical service panel is sufficient to supply a new or replacement air conditioner, as calculated according to the requirements of California Electrical Code Article 220.83 or 220.87. Documentation of electrical load calculations in accordance with Article 220 must be submitted to the enforcement agency prior to permitting for both the heat pump and proposed air conditioner.
Exception 2 to Section A4.204.1.1: Where the required capacity of a heat pump to meet the system selection requirements of Section 150.0(h)5 is greater than or equal to 12,000 Btu/h more than the required capacity of an air conditioner to meet the design cooling load. Documentation of heating and cooling load calculations in accordance with 150.0(h) must be submitted to the enforcement agency prior to permitting for both the heat pump and proposed air conditioner.
A4.204.1.2 Altered pool and/or spa heating for existing multifamily buildings. Alteration of an existing multifamily pool and/or spa heating system shall meet the following:
Heating source sizing. Heating systems or equipment for pools or spas shall meet one of the sizing requirements of Items 1 through 5 below:
- A solar pool heating system with a solar collector surface area that is equivalent to 65 percent or greater of the surface areas of the pool or spa or a combination of both respectively; or
- A heat pump pool heater as the primary heating system that meets the sizing requirements of Reference Joint Appendix JA16.3. The control for the heat pump pool heater shall meet the requirements specified in Title 24, Part 6, Section 110.4(d). The supplementary heater can be of any energy source; or
- A heating system that derives at least 60 percent of the annual heating energy from on-site renewable energy or on-site recovered energy; or
- A combination of a solar pool heating system and heat pump pool heater without any additional supplementary heater; or
- A pool heating system determined by the Energy Commission Executive Director to use no more energy than the systems specified in Item 1, 2, 3, or 4 above.
Exception 1 to A4.204.1.2: Portable electric spas compliant with 20 CCR, Section 1605.3(g)(7) of the Appliance Efficiency Regulations.
Exception 2 to A4.204.1.2: A pool or spa that is heated solely by a solar pool heating system without any supplementary heater.
Exception 3 to A4.204.1.2: An existing building with inadequate Solar Access Roof Area (SARA) as specified in Title 24, Part 6, Section 170.2(f) for a solar pool heating system to be installed.
Exception 4 to A4.204.1.2: Heating systems which are used exclusively for permanent spa applications in existing buildings with gas availability.
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25402, 25402.1, 25402.4 and 25402.8, Public Resources Code.
CRC § 204.1.1 High relevance — show source text
A4.204.1.1 Altered space-conditioning system serving existing single-family dwelling units – mechanical cooling. When a space-conditioning system serving an existing single-family dwelling unit is altered in Climate Zones 1 through 14 and 16 by installation or replacement of an air conditioner, the altered system shall comply with either a or b below in addition to the requirements for installation specified by Title 24, Part 6, Sections 150.2(b)1E and 150.2(b)1F: a. A heat pump shall be the primary heating source and sized according to the system selection requirements specified by Title 24, Part 6 of Section 150.0(h)5. Supplemental heating may be provided by an existing gas furnace or existing electric resistance heating; or b. An air conditioner shall meet the following requirements: i. R-8 duct insulation for ducts located in unconditioned space; and ii. The duct system measured air leakage shall be equal to or less than 5 percent of the system air handler airflow as confirmed through field verification and diagnostic testing, per the requirements in Title 24, Part 6, Reference Residential Appendix Section RA3.1.4.3.1; and iii. Demonstrate, in every control mode, airflow greater than or equal to 400 CFM per ton of nominal cooling capacity through the return grilles, and an air-handling unit fan efficacy less than or equal to 0.35 W/CFM. The airflow rate and fan efficacy requirements in this section shall be confirmed through field verification and diagnostic testing, following the procedures outlined in Title 24, Part 6, Reference Residential Appendix RA3.3; and iv. In all climate zones refrigerant charge verification requirements shall meet the requirements in Title 24, Part 6 Section 150.2(b)1Fiib; and v. Vented attics shall have insulation installed to achieve a U -factor of 0.020 or insulation installed at the ceiling level shall result in an insulated thermal resistance of R-49 or greater for the insulation alone; and vi. Air seal all accessible areas of the ceiling plane between the attic and the conditioned space in accordance with the requirements in Title 24, Part 6 Section 150.2(b)1Jii.
Exception 1 to Section A4.204.1.1: Where the capacity of the existing main electrical service panel is insufficient to supply the electrical capacity of a heat pump and where the existing main electrical service panel is sufficient to supply a new or replacement air conditioner, as calculated according to the requirements of California Electrical Code Article 220.83 or 220.87. Documentation of electrical load calculations in accordance with Article 220 must be submitted to the enforcement agency prior to permitting for both the heat pump and proposed air conditioner.
Exception 2 to Section A4.204.1.1: Where the required capacity of a heat pump to meet the system selection requirements of Section 150.0(h)5 is greater than or equal to 12,000 Btu/h more than the required capacity of an air conditioner to meet the design cooling load. Documentation of heating and cooling load calculations in accordance with 150.0(h) must be submitted to the enforcement agency prior to permitting for both the heat pump and proposed air conditioner.
A4.204.1.2 Altered pool and/or spa heating for existing multifamily buildings. Alteration of an existing multifamily pool and/or spa heating system shall meet the following:
Heating source sizing. Heating systems or equipment for pools or spas shall meet one of the sizing requirements of Items 1 through 5 below: 1.
CRC § 204.1 High relevance — show source text
** Buildings complying with the second level of advanced energy efficiency shall have an Energy Budget that is no greater than indicated below, depending on building type and the type of energy systems included in the building project. If the newly constructed building or addition does not include indoor lighting or mechanical systems, then no additional performance requirements above Title 24, Part 6 are required.
- For nonresidential building projects that include indoor lighting or mechanical systems, but not both: No greater than 90 percent of the Title 24, Part 6, Energy Budget for the Standard Design Building as calculated by compliance software certified by the Energy Commission.
- For nonresidential building projects that include indoor lighting and mechanical systems: No greater than 85 percent of the Title 24, Part 6, Energy Budget for the Standard Design Building as calculated by compliance software certified by the Energy Commission.
- For high-rise residential and hotel/motel building projects: No greater than 95 percent of the Title 24, Part 6, Energy Budget for the Standard Design Building as calculated by compliance software certified by the Energy Commission.
Note: For Energy Budget calculations, high-rise residential and hotel/motel buildings are considered nonresidential buildings.
SECTION A5.204—MANDATORY REQUIREMENTS FOR ALTERATIONS TO EXISTING BUILDINGS
A5.204.1 Energy efficiency . Alterations to existing nonresidential buildings shall comply with Section A5.204.1.1.
A5.204.1.1 Altered pool and/or spa heating for existing nonresidential buildings . Alteration of existing nonresidential pool and/or spa heating system shall meet the following.
Heating source sizing. Heating systems or equipment for pools or spas shall meet one of the sizing requirements of Items 1 through 5 below:
- Solar pool heating system with a solar collector surface area that is equivalent to 65 percent or greater of the surface areas of the pool or spa or a combination of both respectively; or
- A heat pump pool heater as the primary heating system that meets the sizing requirements of Reference Joint Appendix JA16.3. The control for the heat pump pool heater shall meet the requirements specified in Section 110.4(d). The supplementary heater can be of any energy source; or
- A heating system that derives at least 60 percent of the annual heating energy from on-site renewable energy or on-site recovered energy; or
- A combination of a solar pool heating system and heat pump pool heater without any additional supplementary heater;
or
- A pool heating system determined by the Energy Commission Executive Director to use no more energy than the systems specified in Item 1, 2, 3, or 4 above.
Exception 1 to A5.204.1.1: Portable electric spas compliant with 20 CCR, Section 1605.3(g)(7) of the Appliance Efficiency Regulations.
Exception 2 to A5.204.1.1: A pool or spa that is heated solely by a solar pool heating system without any supplementary heater.
Exception 3 to A5.204.1.1: An existing building with inadequate Solar Access Roof Area (SARA) as specified in Section 140.10(a) for a solar pool heating system to be installed.
Exception 4 to A5.204.1.1: Heating systems which are used exclusively for permanent spa applications in existing buildings with gas availability.
SECTION A5.211—RESERVED
SECTION A5.212—ELEVATORS, ESCALATORS AND OTHER EQUIPMENT
CRC § 204.1 High relevance — show source text
- Lighting for industrial sites, including but not limited to, rail yards, maritime shipyards and docks, piers and marinas, chemical and petroleum processing plants, and aviation facilities.
- Lighting of tunnels, bridges, stairs, wheelchair elevator lifts for American with Disabilities Act (ADA) compliance, and ramps that are not parking garage ramps.
- In theme parks: outdoor lighting only for themes and special effects.
- Lighting for outdoor theatrical and other outdoor live performances, provided that these lighting systems are additions to area lighting systems and are controlled by a multi-scene or theatrical cross-fade control station accessible only to authorized operators.
- Outdoor lighting systems for qualified historical buildings, as defined in the California Historical Building Code (Title 24, Part 8), if they consist solely of historical lighting components or replicas of historical lighting components. If lighting systems for qualified historical buildings contain some historical lighting components or replicas of historical components, combined with other lighting components, only those historical or historical replica components are exempt. All other outdoor lighting systems for qualified historical buildings shall not be exempted.
APPENDIX A4-10 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE
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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES
SECTION A4.204 — REQUIREMENTS FOR ALTERATIONS TO EXISTING BUILDINGS
A4.204.1 Energy efficiency. Alterations to existing residential buildings shall comply with Sections A4.204.1.1 and A4.204.1.2.
A4.204.1.1 Altered space-conditioning system serving existing single-family dwelling units – mechanical cooling. When a space-conditioning system serving an existing single-family dwelling unit is altered in Climate Zones 1 through 14 and 16 by installation or replacement of an air conditioner, the altered system shall comply with either a or b below in addition to the requirements for installation specified by Title 24, Part 6, Sections 150.2(b)1E and 150.2(b)1F: a. A heat pump shall be the primary heating source and sized according to the system selection requirements specified by Title 24, Part 6 of Section 150.0(h)5. Supplemental heating may be provided by an existing gas furnace or existing electric resistance heating; or b. An air conditioner shall meet the following requirements: i. R-8 duct insulation for ducts located in unconditioned space; and ii. The duct system measured air leakage shall be equal to or less than 5 percent of the system air handler airflow as confirmed through field verification and diagnostic testing, per the requirements in Title 24, Part 6, Reference Residential Appendix Section RA3.1.4.3.1; and iii. Demonstrate, in every control mode, airflow greater than or equal to 400 CFM per ton of nominal cooling capacity through the return grilles, and an air-handling unit fan efficacy less than or equal to 0.35 W/CFM. The airflow rate and fan efficacy requirements in this section shall be confirmed through field verification and diagnostic testing, following the procedures outlined in Title 24, Part 6, Reference Residential Appendix RA3.3; and iv.
CRC § 110.4 Medium relevance — show source text
A heat pump pool heater as the primary heating system that meets the sizing requirements of Reference Joint Appendix JA16.3. The control for the heat pump pool heater shall meet the requirements specified in Title 24, Part 6, Section 110.4(d). The supplementary heater can be of any energy source; or 3. A heating system that derives at least 60 percent of the annual heating energy from on-site renewable energy or on-site recovered energy; or 4. A combination of a solar pool heating system and heat pump pool heater without any additional supplementary heater; or 5. A pool heating system determined by the Energy Commission Executive Director to use no more energy than the systems specified in Item 1, 2, 3, or 4 above.
Exception 1 to A4.204.1.2: Portable electric spas compliant with 20 CCR, Section 1605.3(g)(7) of the Appliance Efficiency Regulations.
Exception 2 to A4.204.1.2: A pool or spa that is heated solely by a solar pool heating system without any supplementary heater.
Exception 3 to A4.204.1.2: An existing building with inadequate Solar Access Roof Area (SARA) as specified in Title 24, Part 6, Section 170.2(f) for a solar pool heating system to be installed.
Exception 4 to A4.204.1.2: Heating systems which are used exclusively for permanent spa applications in existing buildings with gas availability.
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25402, 25402.1, 25402.4 and 25402.8, Public Resources Code.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-11
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APPENDIX A4-12 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE
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A4 RESIDENTIAL VOLUNTARY MEASURES
DIVISION A4.3 – WATER EFFICIENCY AND CONSERVATION
SECTION A4.301—GENERAL (RESERVED)
SECTION A4.302—DEFINITIONS (RESERVED)
SECTION A4.303—INDOOR WATER USE
A4.303.1 Kitchen faucets. The maximum flow rate of kitchen faucets shall not exceed 1.5 gallons per minute at 60 psi. Kitchen faucets may temporarily increase the flow above the maximum rate, but not to exceed 2.2 gallons per minute at 60 psi, and must default to a maximum flow rate of 1.5 gallons per minute at 60 psi.
Note: Where complying faucets are unavailable, aerators or other means may be used to achieve reduction.
A4.303.2 Alternate water sources for nonpotable applications. Alternate nonpotable water sources are used for indoor potable water reduction. Alternate nonpotable water sources shall be installed in accordance with the California Plumbing Code.
A4.303.3 Appliances. Install at least one qualified ENERGY STAR dishwasher or clothes washer.
Note: See Section A5.303.3 for nonresidential dishwashers and clothes washers.
CRC § 110.4 Medium relevance — show source text
TABLE 110.4-A—HEATING EQUIPMENT STANDARDS Col2 HEATING ENERGY SOURCE STANDARD Electric Resistance UL 1261 Gas-fired ANSI Z21.56/CSA 4.7a Heat Pump AHRI 1160 and one of the following: CSA C22.2 No. 236, UL 1995, or UL/CSA 60335-2-40 Solar ICC/APSP 902/SRCC 400 for solar pool heaters, ICC 901/SRCC 100 for solar collectors - Piping. At least 18 inches of horizontal or vertical pipe shall be installed between the filter and the heater or dedicated suction and return lines, or built-in or built-up connections shall be installed to allow for the future addition of solar heating equipment;
- Covers. Outdoor pools and/or spa with electric or gas heating equipment shall be installed with a pool cover.
- Directional inlets and time switches for pools. If the system or equipment is for a pool: i. The pool shall have directional inlets that adequately mix the pool water; and ii. A time switch or similar control mechanism shall be permanently installed as part of a pool water circulation control system that will allow all pumps to be set or programmed to run only during off-peak electric demand period, and for the minimum time necessary to maintain the water in the condition required by applicable public health standards.
(c) Heating source sizing. Heating systems or equipment for pools and/or spas shall meet one of the sizing requirements 1 through 5 below:
- A solar pool heating system with a solar collector surface area that is equivalent to the following: A. For nonresidential and multifamily buildings, 65 percent or greater of the pool and/or spa surface area. B. For single-family buildings, 60 percent or greater of the pool and/or spa surface area.
- A heat pump pool heater as the primary heating system that meets the sizing requirements of Reference Joint Appendix JA16.3. The supplementary heater can be of any energy source; or
- A heating system that derives at least 60 percent of the annual heating energy from on-site renewable energy or on-site recovered energy.
- A combination of a solar pool heating system and heat pump pool heater without any additional supplementary heater; or
- A pool heating system determined by the Executive Director to use no more energy than the systems specified in Items 1, 2, 3, or 4 above.
Exception 1 to Section 110.4(c): Portable electric spas compliant with 20 CCR §1605.3(g)(7) of the Appliance Efficiency Regulations.
Exception 2 to Section 110.4(c): Alterations to existing pools and/or spas with existing heating systems or equipment.
Exception 3 to Section 110.4(c): A pool and/or spa that is heated solely by a solar pool heating system without any backup heater.
Exception 4 to Section 110.4(c): Heating systems that are used exclusively for permanent spa applications in existing buildings with gas availability.
Exception 5 to Section 110.4(c): Heating systems that are used exclusively for permanent spa applications where there is an inadequate Solar Access Roof Area (SARA) as specified in Section 150.1(c)14 for a solar pool heating system to be installed.
CRC § 110.4 Medium relevance — show source text
A solar pool heating system with a solar collector surface area that is equivalent to the following: A. For nonresidential and multifamily buildings, 65 percent or greater of the pool and/or spa surface area. B. For single-family buildings, 60 percent or greater of the pool and/or spa surface area. 2. A heat pump pool heater as the primary heating system that meets the sizing requirements of Reference Joint Appendix JA16.3. The supplementary heater can be of any energy source; or 3. A heating system that derives at least 60 percent of the annual heating energy from on-site renewable energy or on-site recovered energy. 4. A combination of a solar pool heating system and heat pump pool heater without any additional supplementary heater; or 5. A pool heating system determined by the Executive Director to use no more energy than the systems specified in Items 1, 2, 3, or 4 above.
Exception 1 to Section 110.4(c): Portable electric spas compliant with 20 CCR §1605.3(g)(7) of the Appliance Efficiency Regulations.
Exception 2 to Section 110.4(c): Alterations to existing pools and/or spas with existing heating systems or equipment.
Exception 3 to Section 110.4(c): A pool and/or spa that is heated solely by a solar pool heating system without any backup heater.
Exception 4 to Section 110.4(c): Heating systems that are used exclusively for permanent spa applications in existing buildings with gas availability.
Exception 5 to Section 110.4(c): Heating systems that are used exclusively for permanent spa applications where there is an inadequate Solar Access Roof Area (SARA) as specified in Section 150.1(c)14 for a solar pool heating system to be installed.
(d) Controls for heat pump pool heaters with supplementary heating. Heat pump pool heaters with supplementary heaters shall have controls that meet the following:
- A supplementary heater shall not operate when the heating load can be met by the heat pump pool heater alone; and
- 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.
SECTION 110.5—NATURAL GAS CENTRAL FURNACES, COOKING EQUIPMENT, POOL AND SPA HEATERS, AND FIREPLACES: PILOT LIGHTS PROHIBITED
Any natural gas system or equipment listed below may be installed only if it does not have a continuously burning pilot light:
(a) Fan-type central furnaces.
54 2025 CALIFORNIA ENERGY CODE
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ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS
(b) Household cooking appliances.
Exception to Section 110.5(b): Household cooking appliances without an electrical supply voltage connection and in which each pilot consumes less than 150 Btu/hr.
(c) Pool heaters.
(d) Spa heaters.
(e) Indoor and outdoor fireplaces.
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.8, and 25943, Public Resources Code.
CRC § 25218.5 Medium relevance — show source text
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.8, and 25943, Public Resources Code.
SECTION 110.4—MANDATORY REQUIREMENTS FOR POOL AND SPA SYSTEMS AND EQUIPMENT
(a) Certification by manufacturers. Any pool theater for a pool, spa, or a pool and spa combination shall be installed only if the manufacturer has certified that the system or equipment has all of the following:
Efficiency. Equipment subject to State or federal appliance efficiency standards shall comply with the applicable provisions of Section 110.1; and
On-off switch. A readily accessible on-off switch, mounted on the outside of the heater that allows shutting off the heater without adjusting the thermostat setting; and
Instructions. A permanent, easily readable and weatherproof plate or card that provides the energy efficiency rating and instruction for the energy efficient operation of the pool and/or spa heater; and
2025 CALIFORNIA ENERGY CODE 53
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS
(b) Installation. Any pool and/or spa system or equipment shall meet the following requirements:
- Heating equipment. Equipment installed to heat water for pools and/or spas shall be selected from equipment meeting the standards shown in Table 110.4-A.
TABLE 110.4-A—HEATING EQUIPMENT STANDARDS Col2 HEATING ENERGY SOURCE STANDARD Electric Resistance UL 1261 Gas-fired ANSI Z21.56/CSA 4.7a Heat Pump AHRI 1160 and one of the following: CSA C22.2 No. 236, UL 1995, or UL/CSA 60335-2-40 Solar ICC/APSP 902/SRCC 400 for solar pool heaters, ICC 901/SRCC 100 for solar collectors - Piping. At least 18 inches of horizontal or vertical pipe shall be installed between the filter and the heater or dedicated suction and return lines, or built-in or built-up connections shall be installed to allow for the future addition of solar heating equipment;
- Covers. Outdoor pools and/or spa with electric or gas heating equipment shall be installed with a pool cover.
- Directional inlets and time switches for pools. If the system or equipment is for a pool: i. The pool shall have directional inlets that adequately mix the pool water; and ii. A time switch or similar control mechanism shall be permanently installed as part of a pool water circulation control system that will allow all pumps to be set or programmed to run only during off-peak electric demand period, and for the minimum time necessary to maintain the water in the condition required by applicable public health standards.
(c) Heating source sizing. Heating systems or equipment for pools and/or spas shall meet one of the sizing requirements 1 through 5 below: 1.
CRC § 110.4 Medium relevance — show source text
Solar pool heating system with a solar collector surface area that is equivalent to 65 percent or greater of the surface areas of the pool or spa or a combination of both respectively; or 2. A heat pump pool heater as the primary heating system that meets the sizing requirements of Reference Joint Appendix JA16.3. The control for the heat pump pool heater shall meet the requirements specified in Section 110.4(d). The supplementary heater can be of any energy source; or 3. A heating system that derives at least 60 percent of the annual heating energy from on-site renewable energy or on-site recovered energy; or 4. A combination of a solar pool heating system and heat pump pool heater without any additional supplementary heater;
or
- A pool heating system determined by the Energy Commission Executive Director to use no more energy than the systems specified in Item 1, 2, 3, or 4 above.
Exception 1 to A5.204.1.1: Portable electric spas compliant with 20 CCR, Section 1605.3(g)(7) of the Appliance Efficiency Regulations.
Exception 2 to A5.204.1.1: A pool or spa that is heated solely by a solar pool heating system without any supplementary heater.
Exception 3 to A5.204.1.1: An existing building with inadequate Solar Access Roof Area (SARA) as specified in Section 140.10(a) for a solar pool heating system to be installed.
Exception 4 to A5.204.1.1: Heating systems which are used exclusively for permanent spa applications in existing buildings with gas availability.
SECTION A5.211—RESERVED
SECTION A5.212—ELEVATORS, ESCALATORS AND OTHER EQUIPMENT
A5.212.1 Elevators and escalators. In buildings with more than one elevator or two escalators, provide systems and controls to reduce the energy demand of elevators and escalators as follows. Document systems operation and controls in the project specifications and commissioning plan.
A5.212.1.1 Elevators. Traction elevators shall have a regenerative drive system that feeds electrical power back into the building grid when the elevator is in motion.
A5.212.1.1.1 Car lights and fan. A parked elevator shall turn off its car lights and fan automatically until the elevator is called for use.
A5.212.1.2 Escalators. An escalator shall have a Variable Voltage Variable Frequency (VVVF) motor drive system that is fully regenerative when the escalator is in motion.
A5.212.1.4 Controls. Controls that reduce energy demand shall meet requirements of CCR, Title 8, Chapter 4, Subchapter 6 and shall not interrupt emergency operations for elevators required in CCR, Title 24, Part 2, California Building Code.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A5-15
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX A5 — NONRESIDENTIAL VOLUNTARY MEASURES
SECTION A5.213—ENERGY EFFICIENT FRAMING
CRC § 8-40 Medium relevance — show source text
. . . . . . . . . . . . . 8-40
APPENDIX A4 RESIDENTIAL
VOLUNTARY MEASURES. . . . . . . . . . . . . . . . . APPENDIX A4-3
A4.1 Planning and Design . . . . . . . . . . . . . . . . . APPENDIX A4-3 A4.2 Energy Efficiency . . . . . . . . . . . . . . . . . . . . APPENDIX A4-9 A4.3 Water Efficiency and Conservation . . . APPENDIX A4-13 A4.4 Material Conservation and Resource Efficiency . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A4-15 A4.5 Environmental Quality . . . . . . . . . . . . . . APPENDIX A4-19 A4.6 Tier 1 and Tier 2 . . . . . . . . . . . . . . . . . . . . APPENDIX A4-21
Division A4.6—Residential Occupancies Application Checklist . . . . . . . . . . . . . APPENDIX A4-23 A4.7 Residential Model Ordinance . . . . . . . . . APPENDIX A4-31
APPENDIX A5 NONRESIDENTIAL
VOLUNTARY MEASURES. . . . . . . . . . . . . . . . . APPENDIX A5-3
A5.1 Planning and Design . . . . . . . . . . . . . . . . . APPENDIX A5-3 A5.2 Energy Efficiency . . . . . . . . . . . . . . . . . . . APPENDIX A5-13 A5.3 Water Efficiency and Conservation . . . APPENDIX A5-19 A5.4 Material Conservation and Resource Efficiency . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A5-25 A5.5 Environmental Quality . . . . . . . . . . . . . . APPENDIX A5-35 A5.6 Voluntary Tiers . . . . . . . . . . . . . . . . . . . . . APPENDIX A5-41 A5.601 CALGren Tier 1 and Tier 2. . . . . . . . . . APPENDIX A5-41
A5.602 CALGreen Verification Guidelines Mandatory Measures Checklist . . . . . . . . . . . . . . . APPENDIX A5-44
A5.602.1 CALGreen Verification Guidelines
Tier 1 Checklist . . . . . . . . . . . . . . . . . APPENDIX A5-48
A5.602.2 CALGreen Verification Guidelines
Tier 2 Checklist . . . . . . . . . . . . . . . . . APPENDIX A5-55
APPENDIX A6 VOLUNTARY STANDARDS FOR HEALTH
CRC § 0.40 Medium relevance — show source text
| |Window film|The_U_-factor of 0.40 and
SHGC value of 0.35.|The existing fenestration in the alteration
shall be based on Tables 110.6-A and 110.6-B.| |Service water heating systems|The requirements of Section 140.5 without solar water heating requirements.|The requirements of Section 140.5 without solar water heating requirements.| |Roofing products|The requirements of Section 141.0(b)2B.|The requirements of Section 141.0(b)2B.| |Lighting system|The requirements of Sections 141.0(b)2F through 141.0(b)2K.|The requirements of Sections 141.0(b)2F through 141.0(b)2K.| |All other measures|The proposed efficiency levels.|The proposed efficiency levels.|2025 CALIFORNIA ENERGY CODE 155
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES— ADDITIONS, ALTERATIONS AND REPAIRS
TABLE 141.0-F—CONTROL REQUIREMENTS FOR INDOOR LIGHTING SYSTEM ALTERATIONS Col2 Col3 Col4 CONTROL SPECIFICATIONS CONTROL SPECIFICATIONS PROJECTS COMPLYING WITH
SECTION 141.0(B)2IiPROJECTS COMPLYING WITH
SECTION 141.0(B)2Iii OR
141.0(B)2IiiiManual Area Controls 130.1(a)1 Required Required Manual Area Controls 130.1(a)2 Required Required Manual Area Controls 130.1(a)3 Only required for new or completely
replaced circuitsOnly required for new or completely
replaced circuitsMulti-Level Controls 130.1(b) Required Not Required Automatic Shut-off Controls 130.1(c)1 Required Required Automatic Shut-off Controls 130.1(c)2 Required Required Automatic Shut-off Controls 130.1(c)3 Required Required Automatic Shut-off Controls 130.1(c)4 Required Required Automatic Shut-off Controls 130.1(c)5 Required Required Automatic Shut-off Controls 130.1(c)6 Required Required; except for 130.1(c)6D Automatic Shut-off Controls 130.1(c)8 Required Required Daylight Responsive
Controls130.1(d) Required Not Required Demand Responsive
Controls110.12(a) and 110.12(c) Required Not Required B. The standard design for an altered component shall be the higher efficiency of existing conditions or the requirements of Section 141.0(b)2. For components not being altered, the standard design shall be based on the unaltered existing conditions such that the standard and proposed designs for these components are identical. C. When the third party verification option is specified, all components proposed for alteration, for which the additional credit is taken, must be verified. The Executive Director shall determine the qualifications required by the third party inspector. D. The proposed design shall be based on the actual values of the altered components.
CRC § 110.3 Medium relevance — show source text
For HPWH installations with ducts, the following requirements shall be met: a. The space joined to the installation space via ducts shall meet the minimum volume of Section 110.3(c)7B2 above, minus the volume of the HPWH installation space; and b. All duct connections and building penetrations shall be sealed; and c. Exhaust air ducts and all ducts which cross pressure boundaries shall be insulated to minimum of R-6; and
d. Where only the HPWH inlet or outlet is ducted, installation space shall include permanent openings that consist of a single layer of fixed flat slat louvers or grilles in the bottom half of the room, and/or a door undercut. With a ducted inlet, the minimum NFA shall be equal to the cross-sectional area of the duct. With a ducted exhaust, the minimum NFA shall be the larger of 20 square inches or the minimum NFA provided by the manufacturer for this method; and e. Where the inlet and outlet ducts both terminate within the same pressure boundary, airflow from the termination points shall be diverted away from each other. Note: Ducting only the inlet or the exhaust across the pressure boundary could interfere with balanced ventilation systems. This should be considered when specifying HPWH location and ventilation method.
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.8, and 25943, Public Resources Code.
SECTION 110.4—MANDATORY REQUIREMENTS FOR POOL AND SPA SYSTEMS AND EQUIPMENT
(a) Certification by manufacturers. Any pool theater for a pool, spa, or a pool and spa combination shall be installed only if the manufacturer has certified that the system or equipment has all of the following:
Efficiency. Equipment subject to State or federal appliance efficiency standards shall comply with the applicable provisions of Section 110.1; and
On-off switch. A readily accessible on-off switch, mounted on the outside of the heater that allows shutting off the heater without adjusting the thermostat setting; and
Instructions. A permanent, easily readable and weatherproof plate or card that provides the energy efficiency rating and instruction for the energy efficient operation of the pool and/or spa heater; and
2025 CALIFORNIA ENERGY CODE 53
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS
(b) Installation. Any pool and/or spa system or equipment shall meet the following requirements:
- Heating equipment. Equipment installed to heat water for pools and/or spas shall be selected from equipment meeting the standards shown in Table 110.4-A.
Frequently asked questions
Are A4.204.1.1 and A4.204.1.2 mandatory everywhere?
No. These provisions are in Appendix A4 (residential voluntary measures). They become mandatory only if your local jurisdiction has adopted Appendix A4 as part of its local code. Always confirm with your local building department.
If I install a heat pump pool heater, can I keep my gas backup?
Yes. § A4.204.1.2 Item 2 allows a heat pump pool heater as the primary system with a supplementary heater of any energy source, but controls must ensure the supplementary heater does not operate when the heat pump can meet the load. Documentation and proper controls are required.
What documentation do I need to claim an exception (e.g., electrical panel limitation)?
Submit electrical load calculations per the California Electrical Code (Article 220) to the enforcement agency prior to permitting, as required by the exception language under § A4.204.1.1.
Can I meet the pool heating requirement with on‑site renewables?
Yes. § A4.204.1.2 Item 3 permits a heating system that derives at least 60% of the annual heating energy from on‑site renewable or recovered energy as one of the compliance options.
Do I have to perform field tests if I select the air‑conditioner option for a single‑family alteration?
Yes — duct leakage testing, airflow verification (400 CFM/ton), fan efficacy (≤ 0.35 W/CFM), and refrigerant charge verification are required and must follow the referenced Title 24 field verification procedures noted in § A4.204.1.1.
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