CRC · California Residential Code

Solar pool heating and heat pump pool heater controls (A4.204 & Title 24 reference)

Q: Can I use any thermostat logic as long as the backup doesn't run all the time?

No. The code requires the control logic to actively prevent the supplementary heater from operating when the heat pump can meet the load ( § 110.4(d)(1) ). Simple timers or poorly sequenced thermostats that allow both sources to run simultaneously can violate the rule.

Q: If I install a solar system only, do I still need the heat pump control sequencing?

If the pool is heated solely by a solar pool heating system with no supplementary heater, that scenario is an exception in § A4.204.1.2 and the supplementary‑heater control requirement does not apply.

Q: How large must solar collectors be for a multifamily pool to comply?

For multifamily pools the code specifies a solar collector surface area equal to 65 percent or greater of the pool/spa surface area as one compliance option in § A4.204.1.2 .

Q: Where do I find the heat pump sizing rules referenced by A4.204.1.2?

Sizing is required to follow Reference Joint Appendix JA16.3 , which is referenced in § A4.204.1.2 . The JA16.3 text was not included in the files you provided; consult the Title 24 reference appendices for the exact sizing procedure.

Q: Do I still need a pool cover?

Yes — Title 24 requires outdoor pools and/or spas with electric or gas heating equipment to be installed with a pool cover, per § 110.4(b)3 .

If you alter a multifamily pool heating system and choose a heat pump primary, the CRC requires sizing per JA16.3 and controls that make the heat pump the primary source: the backup must remain off when the heat pump can meet demand, and the heat pump’s cut‑on/cut‑off temperatures must be set higher than the backup’s (see § A4.204.1.2 and § 110.4(d)).

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

Buildings altering multifamily pool or spa heating must meet one of the prescribed sizing/heat-source options in § A4.204.1.2 (for existing multifamily) — including a solar pool heating system sized to at least 65 percent of the pool surface or a heat pump pool heater sized per Reference Joint Appendix JA16.3 with required controls. When a heat pump pool heater is the primary heater and a supplementary heater is present, the controls must prevent supplemental operation when the heat pump can meet the load, and must set the heat pump cut‑on/cut‑off temperatures higher than the supplementary heater’s cut‑on/cut‑off, per § 110.4(d).

The single most important rule: when using a heat pump as the primary pool heater with a backup, the controller must make the heat pump the first and primary source — the supplementary heater must only run when the heat pump cannot meet the heating load (see § 110.4(d)).

Requirements in detail

Which projects / section applies

The requirement is stated for alterations of existing multifamily pools/spas in § A4.204.1.2 (the CRC appendix), which references Title 24 Part 6 for the control specifics. § A4.204.1.2 requires choosing one of the listed heating-source sizing options.
The required controls for heat pump + supplementary heater configurations are in § 110.4(d) of Title 24, Part 6 (California Energy Code).

Key decision dimensions (quick reference table)

Decision dimension	Typical values / requirement	Code Reference
Solar collector sizing (multifamily)	65 percent or greater of pool/spa surface area	§ A4.204.1.2
Heat pump primary option	Heat pump sized per Reference Joint Appendix JA16.3; supplementary heater allowed	§ A4.204.1.2
Control behavior for heat pump + supplementary	Supplementary heater shall not operate when the heat pump can meet the load; heat pump cut‑on and cut‑off temperatures must be higher than supplementary heating cut‑on/cut‑off	§ 110.4(d)
Solar readiness piping	At least 18 inches of horizontal or vertical pipe between filter and heater or dedicated suction/return lines to allow future solar addition	§ 110.4(b)2
Pool cover for outdoor pools with gas/electric heaters	Pool cover required	§ 110.4(b)3
Manufacturer requirements (on-off switch & instructions)	Readily accessible ON–OFF switch on outside of heater; permanent energy-efficiency instructions plate	§ 110.4(a)2–3

Controls — precisely what § 110.4(d) requires

Primary rule: A supplementary heater shall not operate when the heating load can be met by the heat pump pool heater alone. This is an absolute functional requirement — the control logic must determine when the heat pump is capable and inhibit the supplementary source accordingly. § 110.4(d)(1)
Temperature sequencing / deadband requirement: The controller must be set so the heat pump cut‑on temperature is higher than the supplementary heater cut‑on temperature, and likewise heat pump cut‑off is higher than supplementary cut‑off. In practice this establishes a control band where the heat pump acts before and stops after the supplementary heater, keeping the supplementary heater from running except when needed. § 110.4(d)(2)

Sizing options summarized (from § A4.204.1.2)

Option 1: Solar pool heating with collector area ≥ 65% of pool/spa surface (multifamily).
Option 2: Heat pump pool heater as primary, sized per JA16.3; controls per § 110.4(d); supplementary heater permitted.
Option 3: System deriving ≥ 60% of annual heating energy from on‑site renewables or recovered energy.
Option 4: Combination of solar + heat pump without additional supplementary heater.
Option 5: Alternative system approved by the Energy Commission Executive Director that uses no more energy than items 1–4.

(See § A4.204.1.2 for full list and exceptions.)

Exceptions & special cases

Portable electric spas that meet Appliance Efficiency Regulations are excepted. Exception 1 to § A4.204.1.2.
Pools heated solely by solar with no supplementary heater are excepted from the supplementary‑heater control requirement (because there is no supplementary heater). Exception 2 to § A4.204.1.2 and Exception 3 to Title 24 Section 110.4(c) cover similar cases.
Projects with inadequate Solar Access Roof Area (SARA) may be excepted per the referenced SARA rules in Title 24 (exceptions listed in § A4.204.1.2). Exception 3 to § A4.204.1.2.
Where JA16.3 sizing or exact heat pump sizing is required, the text in JA16.3 is the controlling sizing reference (the JA16.3 content was not included in the uploaded files). You must consult Reference Joint Appendix JA16.3 for sizing details.

If you need the precise JA16.3 sizing numbers or the full SARA rules, those specific documents/sections were not included in the files you supplied; consult Title 24 Reference Appendices JA16.3 and the applicable solar access section in Part 6 for those details.

Common mistakes

Installing a supplementary heater control that does not reliably detect when the heat pump can meet the load — e.g., using timers only or independent thermostats that allow both sources to run simultaneously. This violates § 110.4(d)(1).
Mis‑setting the temperature thresholds so the supplementary heater’s cut‑on is equal to or higher than the heat pump cut‑on (which can cause the supplementary to run unnecessarily). The code requires the heat pump cut‑on/cut‑off be higher than the supplementary’s per § 110.4(d)(2).
Forgetting to provide 18 in. of pipe or built connections for future solar when installing a non‑solar heater (solar readiness) as required by § 110.4(b)2.
Omitting the required readily accessible on/off switch on the outside of pool heaters or failing to provide the permanent operation/efficiency instructions plate (manufacturer requirements in § 110.4(a)).
Assuming A4.204.1.2 applies to single‑family alterations — the 65% solar sizing threshold and the A4 appendix language shown are for multifamily existing pools (§ A4.204.1.2). Confirm occupancy type before applying A4 thresholds.

Worked example — concrete scenario

Scenario: An existing multifamily pool is being altered. Owner chooses a heat pump pool heater as the primary heater and will keep the existing gas backup heater as a supplementary source. Pool target setpoint is 82°F.

Code triggers:

Because the project is an alteration of a multifamily pool and the owner selected a heat pump primary, the heat pump must be sized per JA16.3 and the controls must meet § 110.4(d). § A4.204.1.2 and § 110.4(d) apply.

Control setup that complies with § 110.4(d) (example numeric settings):

Set heat pump cut‑on = 78°F and heat pump cut‑off = 85°F.
Set supplementary heater cut‑on = 75°F and supplementary cut‑off = 82°F.
- Rationale: Heat pump cut‑on (78°F) is higher than supplementary cut‑on (75°F), and heat pump cut‑off (85°F) is higher than supplementary cut‑off (82°F), matching the sequencing requirement in § 110.4(d)(2). The supplementary heater therefore only operates when temperatures drop sufficiently low that the heat pump could not sustain the load.

Operational check (verification):

If pool temp falls to 77°F: heat pump will start (because 77 ≤ 78) and supplementary remains off (75 < 77 < 78).
If pool temp continues to fall below 75°F: supplementary will be permitted to operate (only when heat pump cannot meet load). This meets § 110.4(d)(1).

Note: you must size the heat pump per JA16.3 to ensure it is capable of being the primary heating source (JA16.3 text not included in the provided files).

Related provisions

§ A4.204.1.2 — Altered pool and/or spa heating for existing multifamily buildings (sizing options and reference to controls).
§ 110.4(d) — Controls for heat pump pool heaters with supplementary heating (control sequencing and inhibition).
§ 110.4(b)2 — Solar readiness piping: 18 inches of pipe or dedicated lines between filter and heater.
§ 110.4(b)3 — Pool covers required for outdoor pools with gas/electric heating equipment.
§ 110.4(a)2–3 — Manufacturer certification requirements including a readily accessible ON–OFF switch and permanent energy-efficiency instructions.

Code references

Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:

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.
1. 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.
2. 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.
3. 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:
1. 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
1. 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 § 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:
1. 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
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 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.
CRC § 110.4 High 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.

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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 High 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 § 25218.5 High 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

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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 High 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:
1. A supplementary heater shall not operate when the heating load can be met by the heat pump pool heater alone; and
2. 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.

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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 § 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 § 203.1.2 High relevance — show source text
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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

A4.203.1.2 Prerequisite options. In addition, a minimum of TWO of the efficiency measures specified in Sections A4.203.1.2.1 through A4.203.1.2.7 must be met.

A4.203.1.2.1 Roof deck insulation, or ducts in conditioned space. Meet one of the three options for the location of ducts and air handlers as well as insulation R -values and installation of a radiant barrier as specified in Title 24, Part 6, Section 150.1(c)9A or B:
1. Below roof deck insulation with a minimum R -value of 19; or,
2. Continuous above deck insulation with a minimum R-8 and with an air space present between the roofing and the roof deck; or,
3. All ducts and air handlers in conditioned space as specified in the Title 24, Part 6, Reference Appendix RA3.1.
A4.203.1.2.2 High performance walls. Meet the climate zone dependent U -factor or insulation R -value for either 2x6 or 2x4 framing as specified in Title 24, Part 6, Section 150.1(c)1B: maximum U -factor of 0.048.

A4.203.1.2.3 Compact hot water distribution system. Meet the requirements for installation of Compact Hot Water Distribution Systems specified in the Title 24, Part 6, Reference Appendix RA3.6.5.

A4.203.1.2.4 Drain water heat recovery. Meet the requirements for installation of Drain Water Heat Recovery specified in Title 24, Part 6, Reference Appendix RA4.4.21.

A4.203.1.2.5 High performance vertical fenestration. Meet the climate zone dependent U -factor and Solar Heat Gain Coefficient (SHGC) as rated in accordance with Title 24, Part 6, Section 110.6, and shall have a maximum U -factor of 0.21 in Climate Zones 1 − 16, maximum SHGC of 0.23 in Climate Zones 2, 4, and 6 − 14, and maximum SHGC of 0.20 in Climate Zone 15.

Exception to A4.203.1.2.5: Fenestration in Climate Zones 1, 3, 5, and 16 is not required to comply with the maximum SHGC requirements.

A4.203.1.2.6 Heat pump water heater demand management. For buildings with heat pump water heating, meet the requirements for installation of controls specified by Title 24, Part 6, Reference Appendix JA13.3.3.

A4.203.1.2.7 Battery storage system controls. For buildings with battery storage systems, meet the requirements for installation of controls specified by Title 24, Part 6, Reference Appendix JA12 for either the Time-of-Use Control or Advanced Demand Flexibility Control option.
CRC § 110.4 High 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
1. 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 § 9.2.3.3 Medium relevance — show source text
Delete language to section 9.2.3.3 and reserve section number. 9.2.3.3 Reserved.

Revise Section 9.3.19.1 as follows:*

9.3.19.1* Unless the requirements of 9.2.3.1 or 9.2.3.2 are met, sprinklers shall be installed under exterior roofs, canopies, porte-cochere, balconies, decks or similar projections exceeding 4 ft (1.2 m) in width.

Revise Annex Section A9.3.19.2 as follows:

A9.3.19.2 The presence of planters, newspaper machines and similar items, should not be considered storage.

Add Section 9.3.19.3 as follows:

9.3.19.3 Sprinklers may be omitted for following structures:

(1) Solar photovoltaic panel structures with no use underneath. Signs may be provided, as determined by the enforcing agency prohibiting any use underneath including storage. (2) Solar photovoltaic (PV) panels supported by framing that have sufficient uniformly distributed and unobstructed openings throughout the top of the array (horizontal plane) to allow heat and gases to escape, as determined by the enforcing agency.

Add new Sections 16.9.3.1.3.4 and 16.9.3.1.3.5 as follows:

16.9.3.1.3.4 Where a system includes floor control valves, a hydraulic design information sign containing information for the floor shall be provided at each floor control valve. A hydraulic design information sign shall be provided for each area calculated. The installing contractor shall identify a hydraulically designed sprinkler system with a permanently marked weatherproof metal or rigid plastic sign secured with corrosion resistant wire, chain or other approved means. Such signs shall be placed at the alarm valve, dry pipe valve, preaction valve or deluge valve supplying the corresponding hydraulically designed area.

16.9.3.1.3.5 Control valves, check valves, drain valves, antifreeze valves shall be readily accessible for inspection, testing and maintenance. Valves located more than 7 feet above the finished floor shall be provided with a means of opening and closing the valve from the floor level.

Add new Sections 16.9.10.5, 16.9.10.5.1, 16.9.10.5.1.1, 16.9.10.5.1.2, 16.9.10.5.1.3, 16.9.10.5.1.4, 16.9.10.5.2 as follows:

16.9.10.5 Sectional Valves.

16.9.10.5.1 Private fire service main systems shall have sectional control valves at appropriate points in order to permit sectionalizing the system in the event of a break or for the making of repairs or extensions.

16.9.10.5.1.1 Sectional control valves are not required when the fire service main system serves less than six fire appurtenances.

16.9.10.5.1.2 Sectional control valves shall be indicating valves in accordance with Section 16.9.3.2.
CRC § 6.1507 Medium relevance — show source text
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|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|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
CRC § 1.2 Medium relevance — show source text
ASSEMBLY,
OR METHOD1|APPLICABLE
STANDARDS|POLLUTION
(LOW HAZARD)|POLLUTION
(LOW HAZARD)|CONTAMINATION
(HIGH HAZARD)|CONTAMINATION
(HIGH HAZARD)**|INSTALLATION2,3| |DEVICE, ASSEMBLY,
OR METHOD1|APPLICABLE
STANDARDS|BACK-
SIPHONAGE|BACK-
PRESSURE|BACK-
SIPHONAGE|BACK-
PRESSURE|BACK-
PRESSURE| |Air gap|ASME
A112.1.2|X|––|X|––|See Table 603.3.1 in this chapter.| |Air gap fittings for use
with plumbing fixtures,
appliances, and appurte-
nances|ASME
A112.1.3|X|––|X|––|Air gap fitting is a device with an internal air
gap, and typical installation includes
plumbing fixtures, appliances, and
appurtenances. The critical level shall not be
installed below the flood level rim.| |Antisiphon fill valve
(ballcocks) for gravity
water closet flush tanks
and urinal tanks|ASSE 1002/
ASME
A112.1002/
CSA B125.12|X|––|X|––|Installation of gravity water closet flush tank
and urinal tanks with the fill valve installed
with the critical level not less than 1 inch
above the opening of the overflow pipe.4,5| |Atmospheric vacuum
breaker (consists of a
body, checking member
and atmospheric port)|ASSE 1001 or
CSA B64.1.1|X|––|X|––|Upright position. Have outlet open to
atmosphere. Minimum of 6 inches or listed
distance above all downstream piping and
flood level rim of receptor.4,5| |Backflow preventer for
Carbonated Beverage
Dispensers (two inde-
pendent check valves
with a vent to the atmos-
phere)|ASSE 1022|X|X|X|X|Installation includes carbonated beverage
machines or dispensers. These devices
operate under intermittent or continuous
pressure conditions.| |Backflow preventer with
intermediate atmos-
pheric vent|ASSE 1012|X|X|—|—|Installation of potable water connections to
water boilers. No high-hazard chemicals
shall be introduced into the system using
such devices. Designed to operate under con-
tinuous pressure conditions. May discharge
water.| |Backflow preventer with
intermediate atmospheric
vent and pressure reduc-
ing valve|ASSE 1081|X|X|—|—|Installation of potable water connections to
water boilers. No high-hazard chemicals
shall be introduced into the system using
such devices. Designed to operate under con-
tinuous pressure conditions. May discharge
water.

Frequently asked questions

Can I use any thermostat logic as long as the backup doesn't run all the time?

No. The code requires the control logic to actively prevent the supplementary heater from operating when the heat pump can meet the load (§ 110.4(d)(1)). Simple timers or poorly sequenced thermostats that allow both sources to run simultaneously can violate the rule.

If I install a solar system only, do I still need the heat pump control sequencing?

If the pool is heated solely by a solar pool heating system with no supplementary heater, that scenario is an exception in § A4.204.1.2 and the supplementary‑heater control requirement does not apply.

How large must solar collectors be for a multifamily pool to comply?

For multifamily pools the code specifies a solar collector surface area equal to 65 percent or greater of the pool/spa surface area as one compliance option in § A4.204.1.2.

Where do I find the heat pump sizing rules referenced by A4.204.1.2?

Sizing is required to follow Reference Joint Appendix JA16.3, which is referenced in § A4.204.1.2. The JA16.3 text was not included in the files you provided; consult the Title 24 reference appendices for the exact sizing procedure.

Do I still need a pool cover?

Yes — Title 24 requires outdoor pools and/or spas with electric or gas heating equipment to be installed with a pool cover, per § 110.4(b)3.

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California Residential Code