Title 24 · California Energy Code

When are separate remote heaters or boosters required for high-temperature outlets?

Q: If my building is a hospital, does § 110.3(c)1 still apply?

Not necessarily. Systems covered by California Plumbing Code § 613.0 follow that section instead of § 110.3(c)1. Check CPC § 613 for healthcare‑specific requirements (alarms, recirculation, temperature ranges).

Q: Is an instantaneous (tankless) heater at the fixture an acceptable “booster”?

Yes. The code explicitly allows separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature required by the ASHRAE comparison. § 110.3(c)1

Q: Does the 167,000 Btu/hr threshold refer to input or output rating?

The code text refers to the system’s total capacity in Btu/hr; apply the system’s rated thermal capacity per the equipment/manufacturer data when determining whether the threshold is exceeded. § 110.3(c)1

If your building’s central hot‑water plant is larger than 167,000 Btu/hr and a sink, dishwasher, laundry or other outlet needs hotter water than the system’s service temperature (per ASHRAE), the California Energy Code requires a dedicated remote heater/heat exchanger or booster at that outlet; healthcare or other installations may instead follow the California Plumbing Code § 613.0 rules.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

The basic rule is: on a service hot‑water system with a total capacity greater than 167,000 Btu/hr, any outlet that requires a temperature higher than the service water temperature listed in the ASHRAE Handbook must be supplied by separate remote heaters, heat exchangers, or boosters rather than by the main service heater. This requirement is established in § 110.3(c)1.

If the installed water‑heating plant exceeds 167,000 Btu/hr total capacity and a specific outlet needs hotter water than the system’s service temperature, you must use a separate local heater/booster/heat‑exchanger at that outlet. § 110.3(c)1

Requirements in detail

Scope and trigger

Decision trigger: the system total capacity > 167,000 Btu/hr (bolded because it is the threshold). § 110.3(c)1 .
What “requires higher than service water temperatures”: compare the outlet’s required temperature to the ranges listed in the ASHRAE Handbook, Applications Volume (the code refers to ASHRAE as the temperature table source). § 110.3(c)1 .

What must be provided

If both conditions above are met, provide one of the following at the outlet: separate remote heater, heat exchanger, or booster to supply the higher temperature. § 110.3(c)1 .

Table — Decision matrix (quick reference)

Decision dimension	Threshold / value	Action required	Code Reference
System total capacity	≤ 167,000 Btu/hr	No mandatory separate booster under § 110.3(c)1 (still comply with other temp control rules)	§ 110.3(c)1
System total capacity	> 167,000 Btu/hr	If an outlet's required temp > ASHRAE service temp → provide separate remote heater / heat exchanger / booster at that outlet	§ 110.3(c)1
Specialty facilities (healthcare / appliances)	See California Plumbing Code §613.0	Follow Plumbing Code §613.0 requirements instead of § 110.3(c)1 where that section applies	§ 110.3(c)1 Exception; see § 613.0 (CPC)
Voluntary/green guidance	Mirrors the same requirement in Appendix A6 (nonmandatory guidance)	Same: separate boosters for >167,000 Btu/hr systems when outlets need higher temps	A6.207.3.3.1

Practical definitions (as used by the rule)

System total capacity — the aggregate rated thermal capacity of the service hot‑water system (reported in Btu/hr). The code text uses the phrase “total capacity greater than 167,000 Btu/hr.” § 110.3(c)1 .
Separate remote heater / booster — a dedicated local device (electric or gas instantaneous heater, heat exchanger or booster) installed to raise outlet temperature independently of the main service heater; the code lists these as acceptable supply means. § 110.3(c)1 .

Exceptions & special cases

Exception for systems subject to the California Plumbing Code Section 613.0: where § 613.0 applies (for example many healthcare facility rules), follow CPC § 613.0 instead of § 110.3(c)1. § 110.3(c)1 Exception; see § 613.0 (CPC).
The CPC contains additional, prescriptive rules for high‑temperature requirements in medical, dietary, laundry and dishwashing applications (for example, booster heaters for dishwashing at 125°F–180°F are explicitly acceptable in CPC § 613.2). See § 613.2 and related CPC clauses for these special uses.
The California Green Building (Appendix A6) restates the same threshold and requirement (useful guidance where the Appendix is adopted). See A6.207.3.3.1.

Common mistakes

Assuming the threshold applies per outlet instead of system‑wide: the rule is triggered by the system total capacity (aggregated), not a single appliance’s rating. § 110.3(c)1 .
Forgetting the ASHRAE temperature comparison: you must verify the outlet’s required temperature against the ASHRAE Handbook tables; the code does not list specific outlet temps itself. § 110.3(c)1 .
Not checking CPC § 613.0 where it may control: healthcare and certain institutional installations are governed by the Plumbing Code’s distinct requirements (and alarms/controls) — don’t apply § 110.3(c)1 blindly if § 613.0 applies. § 110.3(c)1 Exception; § 613.0 (CPC) .
Using a single oversized main heater to serve high‑temp outlets without a dedicated booster when the system capacity exceeds the threshold — that violates the separate‑booster requirement. § 110.3(c)1 .

Worked example — concrete scenario with numbers

Scenario: A hotel has a central service hot‑water plant totaling 200,000 Btu/hr input capacity. The kitchen dishwashing machine requires 160°F at the point of use, and the main service heater supplies domestic hot water at 140°F (per owner/manufacturer settings and ASHRAE service temperature tables).

Step 1 — Compare system capacity to threshold: 200,000 Btu/hr > 167,000 Btu/hr, so § 110.3(c)1 is triggered. § 110.3(c)1 .
Step 2 — Compare outlet required temp to the ASHRAE service temperature: 160°F > 140°F (service temp) → outlet requires higher temperature. § 110.3(c)1 .
Conclusion — Provide a separate remote booster or heat exchanger dedicated for the dishwasher (for example, an on‑dishwasher booster heater rated to deliver 160°F), rather than relying on the central plant to raise the entire distribution temperature. § 110.3(c)1 .

Contrast: If the plant had been 150,000 Btu/hr, the separate booster requirement under § 110.3(c)1 would not be mandatory (other codes/health rules may still require boosters for sanitization; check CPC where applicable). § 110.3(c)1 .

Related provisions

§ 110.3(a)1 — Temperature controls for service water‑heating systems (automatic temperature controls and ASHRAE table references).
§ 110.3(c)2 — Controls for hot water distribution systems (recirculation pumps and heat‑trace systems must be capable of automatic shutoff).
California Plumbing Code § 613.0 — Special provisions for healthcare and other high‑temperature hot water needs; includes requirements for multiple pieces of equipment, booster acceptability for dishwashing and temperature limits/alarms.
A6.207.3.3.1 (Green Building Appendix) — Mirrors § 110.3(c)1: separate remote heaters/boosters for systems >167,000 Btu/hr when needed.

Code references

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

§ 110.3 High relevance — show source text
1. Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature. Exception to Section 110.3(c)1: Systems covered by California Plumbing Code Section 613.0 shall instead follow the requirements of that section.
2. Controls for hot water distribution systems. Service hot water systems with circulating pumps or with electrical heat trace systems shall be capable of automatically turning off the system. Exception to Section 110.3(c)2: Systems serving healthcare facilities.
3. Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have: A. External insulation with an installed R -value of at least R-3.5; or
B. Internal and external insulation with a combined R -value of at least R-16; or

C. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot. 4. Water heating recirculation loops serving multiple dwelling units, high-rise residential, hotel/motel, and nonresiden- tial occupancies. A water heating recirculation loop is a type of hot water distribution system that reduces the time needed to deliver hot water to fixtures that are distant from the water heater, boiler or other water heating equipment. The recirculation loop is comprised of a supply portion, connected to branches that serve multiple dwelling units, guest rooms, or fixtures and a return portion that completes the loop back to the water heating equipment. A water heating recirculation loop shall meet the following requirements: A. Air release valve or vertical pump installation. An automatic air release valve shall be installed on the recirculation loop piping on the inlet side of the recirculation pump and no more than 4 feet from the pump. This valve shall be mounted on top of a vertical riser at least 12 inches in length and shall be accessible for replacement and repair. Alternatively, the pump shall be installed on a vertical section of the return line. B. Recirculation loop backflow prevention. A check valve or similar device shall be located between the recirculation pump and the water heating equipment to prevent water from flowing backwards though the recirculation loop. C. Equipment for pump priming. A hose bibb shall be installed between the pump and the water heating equipment. An isolation valve shall be installed between the hose bibb and the water heating equipment. This hose bibb is used for bleeding air out of the pump after pump replacement. D. Pump isolation valves. Isolation valves shall be installed on both sides of the pump. These valves may be part of the flange that attaches the pump to the pipe. One of the isolation valves may be the same isolation valve as in Item C. E. Cold water supply and recirculation loop connection to hot water storage tank. Storage water heaters and boilers shall be plumbed in accordance with the manufacturer’s specifications The cold water piping and the recirculation loop piping shall not be connected to the hot water storage tank drain port. F. Cold water supply backflow prevention. A check valve shall be installed on the cold water supply line between the hot water system and the next closest tee on the cold water supply line.
§ 207.3.2 High relevance — show source text
A6.207.3.2 Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section A6.210.1, subject to the following:
1. If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and
2. If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and
3. Where equipment can serve more than one function, such as both heating and cooling or both space heating and water heating, it shall comply with all the requirements applicable to each function; and
4. Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.
A6.207.3.3 Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment.

A6.207.3.3.1 Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature.

A6.207.3.3.2 Temperature controls for public lavatories. The controls shall limit the outlet temperature to 110°F.

A6.207.3.3.3 Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have:
1. External insulation with an installed R -value of at least R-12; or
2. Internal and external insulation with a combined R -value of at least R-16; or
3. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot.
A6.207.3.3.4 Service water heaters in state buildings. Any newly constructed building constructed by the State shall derive its service water heating from a system that provides at least 60 percent of the energy needed for service water heating from site solar energy or recovered energy.

Exception: Buildings for which the state architect determines that service water heating from site solar energy or recovered energy is economically or physically infeasible.

A6.207.4 Natural gas central furnaces, cooking equipment and pool and spa heaters: 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:
1. Fan-type central furnaces.
2. Household cooking appliances. Exception: Household cooking appliances without an electrical supply voltage connection and in which each pilot consumes less than 150 Btu/hr.
3. Pool heaters.
4. Spa heaters.
A6.207.5 Controls for space-conditioning systems. Space- conditioning systems shall be installed with controls that comply with the applicable requirements of Subsections A6.207.5.1 through A6.207.5.5.

A6.207.5.1 Thermostatic controls for each zone. The supply of heating and cooling energy to each space-conditioning zone or dwelling unit shall be controlled by an individual thermostatic control that responds to temperature within the zone and that meets the applicable requirements of Section A6.207.5.2.
§ 1-19 High relevance — show source text
The leakage rate shall be confirmed through field verification and diagnostic testing, in accordance with procedures set forth in the Reference Nonresidential Appendix NA1 of the California Energy Commission 2008 Building Energy Efficiency Stan- dards for Residential and Nonresidential Buildings.

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A6.1-19

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

A6.207.2.6 Variable air volume control for single zone systems. Effective January 1, 2012, all unitary air conditioning equipment and air-handling units with mechanical cooling capacity at ARI conditions greater than or equal to 110,000 Btu/hr that serve single zones shall be designed for variable supply air volume with their supply fans controlled by two-speed motors, variable speed drives or equipment that has been demonstrated to the Executive Director to use no more energy. The supply fan controls shall modulate down to a minimum of [2] / 3 of the full fan speed or lower at low cooling demand.

A6.207.3 Service water-heating systems and equipment.

A6.207.3.1 Certification by manufacturers. Any service water-heating system or equipment may be installed only if the manufacturer has certified that the system or equipment complies with all of the requirements of this subsection for that system or equipment.

A6.207.3.1.1 Temperature controls for service water-heating systems. Service water-heating systems shall be equipped with automatic temperature controls capable of adjustment from the lowest to the highest acceptable temperature settings for the intended use as listed in Table 2, Chapter 9 of the ASHRAE Handbook, HVAC Applications Volume.

A6.207.3.2 Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section A6.210.1, subject to the following:
1. If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and
2. If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and
3. Where equipment can serve more than one function, such as both heating and cooling or both space heating and water heating, it shall comply with all the requirements applicable to each function; and
4. Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.
A6.207.3.3 Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment.

A6.207.3.3.1 Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature.

A6.207.3.3.2 Temperature controls for public lavatories. The controls shall limit the outlet temperature to 110°F.
§ 110.3 High relevance — show source text
SECTION 110.3—MANDATORY REQUIREMENTS FOR SERVICE WATER-HEATING SYSTEMS AND EQUIPMENT

(a) Certification by manufacturers. Any service water- heating system or equipment may be installed only if the manufacturer has certified that the system or equipment complies with all of the requirements of this subsection for that system or equipment.
1. Temperature controls for service water-heating systems. Service water-heating systems shall be equipped with automatic temperature controls capable of adjustment from the lowest to the highest acceptable temperature settings for the intended use as listed in Table 3, Chapter 50 of the ASHRAE Handbook, HVAC Applications Volume or Table 613.1 of the Cali- fornia Plumbing Code for healthcare facilities. Exception to Section 110.3(a)1: Residential occupancies.
(b) Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section 110.1, subject to the following:
1. If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and
2. If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and
3. Where equipment can serve more than one function, such as both heating and cooling, or both space heating and water heating, it shall comply with all the requirements applicable to each function; and
4. Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.
(c) Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment.
1. Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature. Exception to Section 110.3(c)1: Systems covered by California Plumbing Code Section 613.0 shall instead follow the requirements of that section.
2. Controls for hot water distribution systems. Service hot water systems with circulating pumps or with electrical heat trace systems shall be capable of automatically turning off the system. Exception to Section 110.3(c)2: Systems serving healthcare facilities.
3. Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have: A. External insulation with an installed R -value of at least R-3.5; or
B. Internal and external insulation with a combined R -value of at least R-16; or

C. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot. 4. Water heating recirculation loops serving multiple dwelling units, high-rise residential, hotel/motel, and nonresiden- tial occupancies. A water heating recirculation loop is a type of hot water distribution system that reduces the time needed to deliver hot water to fixtures that are distant from the water heater, boiler or other water heating equipment. The recirculation loop is comprised of a supply portion, connected to branches that serve multiple dwelling units, guest rooms, or fixtures and a return portion that completes the loop back to the water heating equipment.
§ 6.1507 High 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
§ 1.0 High relevance — show source text
D. The outdoor design temperatures for cooling shall be no greater than the 1.0 percent Cooling Dry Bulb and Mean Coincident Wet Bulb values.
1. Outdoor condensing units. A. Clearances. Installed air conditioner and heat pump outdoor condensing units shall have a clearance of at least five (5) feet (1.5 meters) from the outlet of any dryer vent. B. Liquid line drier. Installed air conditioner and heat pump systems shall be equipped with liquid line filter driers if required, as specified by manufacturer’s instructions.
2. Central forced-air heating furnaces. A. Temperature rise. Central forced-air heating furnace installations shall be configured to operate in conformance with the furnace manufacturer’s maximum inlet-to-outlet temperature rise specifications.
3. System selection. A. Equipment sizing and selection shall meet the cooling and heating loads of Sections 150.0(h)1 and 2. B. Systems shall be sized based on ACCA Manual S-2023 in accordance with these requirements: i. Cooling capacity: There is no limit on the minimum capacity. ii. Furnaces: Heating capacity shall be sized based on ACCA Manual S-2023, Table N2.5.
160 2025 CALIFORNIA ENERGY CODE

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SINGLE-FAMILY RESIDENTIAL BUILDINGS— MANDATORY FEATURES AND DEVICES

iii. Heat pump heating capacity: a. Minimum: Heating systems are required to have a heating capacity meeting the minimum requirements of the CBC, not including any supplementary heating. b. Maximum: There is no limit on the maximum heating capacity.
1. Defrost.
A. If a heat pump is equipped with an installer adjustable defrost delay timer, the delay timer shall be set to greater than or equal to 90 minutes. B. The installer shall certify on the Certificate of Installation (CF2R) that the control configuration has been tested in accordance with the testing procedure in the CF2R.

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

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

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

i. Option A:
1. That prevent supplementary heater operation when the heating load can be met by the heat pump alone; and
§ 306.2 Medium relevance — show source text
Forced-air and gravity-type warm air furnaces shall be equipped with a listed air outlet temperature limit control that cannot be set for temperatures exceeding 250°F (121°C). Such controls shall be located in the bonnet or plenum, within 2 feet (610 mm) of the discharge side of the heating element of gravity furnaces or in accordance with the conditions of listing.

Electric duct heaters shall be equipped with an approved automatic reset air outlet temperature limit control that will limit the outlet air temperature to not exceed 200°F (93°C). The electric elements of the heater shall be equipped with fusible links or a manual reset temperature limit control that will prevent outlet air temperature in excess of 250°F (121°C).

306.2 Building Automation Systems. [OSHPD 1] Building automation systems shall provide for localized con- trol in the event of network failure. This capability shall be specified in the construction documentation.

307.0 Labeling.

307.1 Fuel-Burning Appliances. Fuel-burning heating appliances shall bear a permanent and legible factory-applied nameplate on which shall appear:

(1) The name or trademark of the manufacturer.

(2) The approved fuel input rating of the appliance, expressed in Btu/h (kW).

(3) The model number or equivalent.

(4) The serial number.

(5) Instructions for the lighting, operation, and shutdown of the appliance.

(6) The type of fuel approved for use with the appliance.

(7) The symbol of an approved agency certifying compliance of the equipment with recognized standards.

(8) Required clearances from combustible surfaces on which or adjacent to which it is permitted to be mounted.

307.2 Electric Heating Appliances. Electric heating appliances shall bear a permanent and legible factory-applied nameplate on which shall appear:

(1) The name or trademark of the manufacturer.

(2) The model number or equivalent.

(3) The serial number.

(4) The electrical rating in volts, amperes (or watts), and, for other than single phase, the number of phases.

(5) The output rating in Btu/h (kW).

(6) The electrical rating in volts, amperes, or watts of each field-replaceable electrical component.

(7) The symbol of an approved agency certifying compliance of equipment with recognized standards.

(8) Required clearances from combustible surfaces on which or adjacent to which it is permitted to be mounted.

An appliance shall be accompanied by clear and complete installation instructions, including required clearances from combustibles other than mounting or adjacent surfaces, and temperature rating of field-installed wiring connections exceeding 140°F (60°C). 307.3 Heat Pump and Electric Cooling Appliances. Heat pumps and electric cooling appliances shall bear a permanent and legible factory-applied nameplate on which shall

appear:

(1) The name or trademark of the manufacturer.

(2) The model number or equivalent.

(3) The serial number.

(4) The amount of refrigerant.

(5) The refrigerant designation.

(6) The factory test pressures or pressures applied.

(7) The electrical rating in volts, amperes, and, for other than single phase, the number of phases.

(8) The output rating in Btu/h (kW).

(9) The electrical rating in volts, amperes, or watts of each field replaceable electrical component.

(10)The symbol of an approved agency certifying compliance of the equipment with recognized standards.
§ 80.6 Medium relevance — show source text
1. Economizers. Each individual cooling system primarily serving computer room shall include either: A. An integrated air economizer capable of providing partial cooling even when additional mechanical cooling is required and capable of providing 100 percent of the expected system cooling load at 65°F to 80.6°F supply air temperature at outside air temperatures of 65°F dry-bulb and below or 50°F wet-bulb and below, and be equipped with a fault detection and diagnostic system as specified by Section 120.2(i); or B. An integrated water economizer capable of providing partial cooling even when additional mechanical cooling is required and capable of providing 100 percent of the expected system cooling load at 65°F to 80.6°F supply air temperature at outside air temperatures of 50°F dry-bulb and below or 45°F wet-bulb and below. Exception 1 to Section 140.9(a)1: Individual computer rooms with an ITE design load under 5 tons (18 kW) in a building that does not have any economizers. Exception 2 to Section 140.9(a)1: A computer room with an ITE design load less than 20 tons (70 kW) may be served by a second fan system without an economizer if it is also served by a fan system with an economizer that also serves other spaces within the building, provided that all of the following are met: i. The economizer system is sized to meet the design cooling load of the computer room when the other spaces within the building are at 50 percent of their design load at outside air temperatures of 65°F dry-bulb and below or 50°F wet-bulb and below; and
ii. An economizer system that can stop service to other spaces in the building when those spaces are unoccupied and serve only the computer rooms. 2. Power consumption of fans. The total fan power at design conditions of each fan system shall not exceed 27 W/kBtu·h of net sensible cooling capacity. 3. Air containment. Computer rooms with air-cooled computers in racks and with an ITE design load exceeding 10 kW (2.8 tons) per room shall include air barriers such that there is no significant air path for computer discharge air to recirculate back to computer inlets without passing through a cooling system.

Exception 1 to Section 140.9(a)3: Expansions of existing computer rooms.

2025 CALIFORNIA ENERGY CODE 141

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NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES—PERFORMANCE AND PRESCRIPTIVE

COMPLIANCE APPROACHES FOR ACHIEVING ENERGY EFFICIENCY

Exception 2 to Section 140.9(a)3: Computer racks with a design load less than 1 kW (0.28 tons) per rack.

Exception 3 to Section 140.9(a)3: Equivalent energy performance based on computational fluid dynamics or other analysis. 4. Alternating current-output uninterruptible power supplies (UPS). Alternating current-output UPS systems serving a computer room shall meet or exceed minimum average efficiencies in Table 140.9-B. Minimum average efficiency for alternating current-output UPS shall meet or exceed calculation and testing requirements identified in ENERGY STAR Program Requirements for Uninterruptible Power Supplies (UPSs) – Eligibility Criteria Version 2.0.

where:

P is the rated output power in watts (W).
§ 110.2 Medium relevance — show source text
ranges:
```
 - Minimum Leaving Evaporator Fluid Temperature: 36°F

- Maximum Leaving Condenser Fluid Temperature: 115°F

  - LIFT ≥ 20°F and ≤ 80°F
```
Centrifugal chillers designed to operate outside of these ranges are not covered by this exception.

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

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

(b) Controls for heat pumps with supplementary heaters.

Control requirements for heat pumps with supplementary heaters in single-family residential buildings are specified in Section 150.0(h)7 and Section 150.0(i)2. Heat pumps with supplementary heaters in nonresidential and multifamily buildings shall have controls:
1. That prevent supplementary heater operation when the heating load can be met by the heat pump alone; and
2. In which the cut-on temperature for heat pump heating is higher than the cut-on temperature for supplementary heating, and the cut-off temperature for heat pump heating is higher than the cut-off temperature for supplementary heating. Exception 1 to Section 110.2(b): The controls may allow supplementary heater operation during: A. Defrost; and
B. Transient periods such as start-ups and following room thermostat setpoint advance, if the controls provide preferential rate control, intelligent recovery, staging, ramping or another control mechanism designed to preclude the unnecessary operation of supplementary heating.

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

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(c) Thermostats. All heating or cooling systems not controlled by a central energy management control system (EMCS) shall have a setback thermostat.
1. Setback capabilities. All thermostats shall have a clock mechanism that allows the building occupant to program the temperature setpoints for at least four periods within 24 hours. Thermostats for heat pumps shall meet the requirements of Section 110.2(b).
Exception to Section 110.2(c): Gravity gas wall heaters, gravity floor heaters, gravity room heaters, noncentral electric heaters, fireplaces or decorative gas appliances, wood stoves, room air conditioners and room air-conditioner heat pumps.

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

(e) Open and closed-circuit cooling towers. All open and closed-circuit cooling tower installations shall comply with the following:
1. Be equipped with conductivity controls that maximize cycles of concentration based on local water quality conditions.
§ 12.5. Medium relevance — show source text
(1) The tank surface is thermally insulated to R-12.5.

(2) A standing pilot light is not installed.

(3) Gas- or oil-fired storage water heaters have a flue damper or fan-assisted combustion. [ASHRAE 90.1:7.4.2]

L 503.3.3 Service Hot Water Piping Insulation. Insulation of hot water and return piping shall meet the provisions in Section L 501.2.

L 503.3.4 Hot Water System Design. Hot water systems shall comply with the following:

(1) Circulating hot water systems shall be arranged so that the circulating pump(s) are capable of being turned off (automatically or manually) where the hot water system is not in operation.

Exception: For healthcare facilities, long term care facilities, hotels, or motels, devices that automatically turn off the circulation pump(s) shall not be required.

(2) Where used to maintain storage tank water temperature, circulating pump(s) shall be equipped with controls limiting operation to a period from the start of the heating cycle to a maximum of 5 minutes after the end of the heating cycle.

(3) The maximum volume of water contained in hot water distribution lines between the water heater and the fixture stop or connection to showers, kitchen faucets, and lavatories shall be determined in accordance with Section L 502.7.

L 503.3.5 Service Water Heating System Con- trols. Service water heating system controls shall comply with Section L 503.3.5(1) and Section L 503.3.5(2).

(1) Temperature controls shall be provided that allow for storage temperature adjustment from 120°F (49°C) or lower to a maximum temperature compatible with the intended use.

Exception: Where the manufacturer’s installation instructions specify a higher minimum thermostat setting to minimize condensation and resulting corrosion. [ASHRAE 90.1:7.4.4.1]

(2) Temperature controlling means shall be provided to limit the maximum temperature of water delivered from lavatory faucets in public facility restrooms to 110°F (43°C). [ASHRAE 90.1:7.4.4.3]

L 503.3.6 Pools. Pool heating systems shall comply with Section L 503.3.6(1) through Section L 503.3.6(3).

2025 CALIFORNIA PLUMBING CODE 511

), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

APPENDIX L

(1) Pool heaters shall be equipped with a readily accessible ON/OFF switch to allow shutting off the heater without adjusting the thermostat setting. Pool heaters fired by natural gas shall not have continuously burning pilot lights. [ASHRAE 90.1:7.4.5.1] (2) Heated pools shall be equipped with a vapor retardant pool cover on or at the water surface. Pools heated to more than 90°F (32°C) shall have a pool cover with a minimum insulation value of R-12.
§ 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:
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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(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.

§ 1703.3 Medium relevance — show source text

TABLE 1703.3

GROUND SOURCE LOOP PIPE FITTINGS

MATERIAL	STANDARD
Cross-linked Polyethylene (PEX)	ASTM F877, ASTM F1055, ASTM F1807, ASTM F1960, ASTM F2080, ASTM F2159, ASTM F2434, ASTM F3347, ASTM F3348, CSA B137.5, ANSI/CSA/IGSHPA C448, NSF/ANSI 358-3
High Density Polyethylene (HDPE)	ASTM D2683, ASTM D3261, ASTM F1055, CSA B137.1, ANSI/CSA/IGSHPA C448, NSF/ANSI 358-1
Polypropylene (PP)	ASTM F2389, CSA B137.11, NSF/ANSI 358-2
Polyethylene of Raised Temperature (PE-RT)	ASTM D3261, ASTM F1055, ASTM F1807, ASTM F2080, ASTM F2159, ASTM F2769, ASTM F3347, ASTM F3348, CSA B137.18, ANSI/CSA/IGSHPA C448, NSF/ANSI 358-4

1703.4 Underground Piping and Submerged Materi- als. Underground and submerged piping for a ground-heat exchanger shall be polyethylene (PE) pipe or tubing in accordance with Section 1703.4.1 and Section 1703.4.1.1, or crosslinked polyethylene (PEX) pipe or tubing in accordance with Section 1703.4.2 and Section 1703.4.2.1.

1703.4.1 Polyethylene (PE). Polyethylene pipe or tubing shall be manufactured in accordance with the standards listed in Table 1703.2. Pipe or tubing shall have a minimum wall thickness equal to SDR-11 and shall have a minimum pressure rating of not less than 160 psi (1103 kPa) at 73°F (23°C).

Polyethylene pipe and tubing shall be manufactured from a PE compound that has a pipe material designation code of PE 3608, PE 3708, PE 3710, PE 4608, PE 4708, or PE 4710 as defined in the applicable standards referenced in Table 1703.2, with a cell classification in accordance with ASTM D3350 appropriate for the material designation code, and a color and ultraviolet stabilizer code of C or E. Code E compounds shall be stabilized against deterioration from unprotected exposure to ultraviolet rays for not less than 3 years in accordance with the test criteria specified in ASTM D2513.

1703.4.1.1 Joining Methods for Polyethylene Pipe or Tubing. Joints between high density polyethylene (HDPE) plastic pipe or tubing and fittings shall be installed in accordance with the manufac

TABLE 1701.11.1

WATER QUALITY [1]

WATER QUALITY TABLE 1703.3

GROUND SOURCE LOOP PIPE FITTINGS

Frequently asked questions

When exactly do I have to look up ASHRAE tables?

Compare the outlet’s required temperature to the “service water temperatures” listed in the ASHRAE Handbook, Applications Volume whenever the system capacity exceeds 167,000 Btu/hr; the code uses ASHRAE as the temperature reference. § 110.3(c)1

If my building is a hospital, does § 110.3(c)1 still apply?

Not necessarily. Systems covered by California Plumbing Code § 613.0 follow that section instead of § 110.3(c)1. Check CPC § 613 for healthcare‑specific requirements (alarms, recirculation, temperature ranges).

Is an instantaneous (tankless) heater at the fixture an acceptable “booster”?

Yes. The code explicitly allows separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature required by the ASHRAE comparison. § 110.3(c)1

Does the 167,000 Btu/hr threshold refer to input or output rating?

The code text refers to the system’s total capacity in Btu/hr; apply the system’s rated thermal capacity per the equipment/manufacturer data when determining whether the threshold is exceeded. § 110.3(c)1

If the main system can be re‑set to a higher service temperature, can I avoid boosters?

Raising the entire service water temperature to meet one outlet is not the intent of § 110.3(c)1 when the system exceeds the threshold; the code requires separate heaters/boosters at the outlet. Also consider scalding risk and other code limits (and CPC healthcare rules) before raising system temperature. § 110.3(c)1

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