After more than a year of hearings and public drafts, the California Energy Commission (CEC) has finished rulemaking and formally adopted the newest versions of the 2025 California Energy Code (Energy Code, Title 24, Part 6), and the voluntary energy efficiency requirements for the 2025 California Green Building Standards Code (CALGreen, Title 24, Part 11). The CALGreen requirements are voluntary on a statewide basis, but localities are free to adopt them in total or amended as mandatory codes.
Under these revised codes, new heating systems for pools and spas will be required to use one of five heating systems that will reduce greenhouse gas emissions and energy consumption.
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 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 Items 1, 2, 3, or 4 above.
The requirement will apply to newly constructed pools and spas, or new heating systems added to existing pools or spas that did not have a heating system previously.
These significant changes are estimated by the California Statewide Codes and Standards Enhancement (CASE) Team to result in 10.2 million therms of natural gas usage savings and 57,574 metric tons of CO2e (carbon dioxide equivalent) reductions expected during the first year. According to the CASE Team, the pool heating aspects of this code change are the highest natural gas and GHG savings measures in the 2025 California portfolio.
In revising and updating the codes, the CEC is responsible to the California state government and citizens for working to achieve reduction in both energy consumption and greenhouse gas emissions to help meet the state’s policy goals. As with all rulemaking, this requires a balanced approach, driven largely by addressing the needs of stakeholders at public hearings and by accepting public comments.
The Pool & Hot Tub Alliance (PHTA) and the California Pool & Spa Association (CPSA) participated throughout this process, submitting fact-based comments at several key junctures when drafts were being developed. As a result, PHTA and CPSA were able to gain significant concessions throughout the process that will have a direct impact on pool and spa designers, builders, owners, and operators throughout California. These changes implemented by CEC offer significant design alternatives as exceptions to the regulation with the five options offered in the Section 110.4(c) of Title 24, Part 6 Mandatory Requirements for Pool and Spa Systems and Equipment, Heat Pump Sizing prescriptive approach, which contains the pertinent pool heating source requirements.
• Exception 1: Portable electric spas compliant with 20 CCR § 1605.3(g)(7) of the Appliance Efficiency Regulations are not regulated by the 2025 CA Energy Code.
• Exception 2: Alterations to existing pools and/or spas with existing heating systems or equipment are exempt from the 2025 CA Energy Code requirements.
• Exception 3: A pool and/or spa that is heated solely by a solar pool heating system without any backup heater is exempted from additional 2025 CA Energy Code heating requirements.
• Exception 4: Heating systems that are used exclusively for permanent spa applications in existing buildings with gas availability will not have to comply with any additional 2025 CA Energy Code spa heating requirements.
• Exception 5: Heating systems that are used exclusively for permanent spa applications where there is inadequate Solar Access Roof Area (SARA) as specified in CA Energy Code Section 150.1(c)14 for a solar pool heating system to be installed.
Gas heater exceptions – PHTA was able to expand exceptions for existing pools and spas with existing gas connections and installed gas heaters to serve pools in multifamily and non-residential buildings (Exception 2 above) in addition to the single-family residential buildings.
The exception would enable pools in all those settings to be replaced with another gas heater when a replacement or update to the pool or spa heating system is needed.
The initial proposed language only provided single-family pools this option for existing gas connections and installed gas heaters.
PHTA successfully argued that size differences between the two heating technologies and greater electrical connection requirements for heat pump pool heaters (HPPH) would make replacement of an old gas pool heater with a properly sized HPPH difficult or impossible in many cases.
The gas heater exceptions were also expanded in the case of heating systems used exclusively for permanent spa installations (Exception 4 above), allowing new spas built in existing buildings with gas availability to also use gas heating systems as well as new spas where there is not adequate solar access roof area for a solar pool heating system to be installed (Exception 5 above).
Heat Pump Pool Heater Sizing Requirements – PHTA was able to get the language relating to proper sizing of a HPPH to include reference to manufacturer sizing requirements as an appropriate reference.
Before this change, the proposed regulations would have forced the use of tables within the regulations to size HPPH, resulting in potential mismatches in many situations.
How CALGreen Differs – The 2025 CALGreen Code does not include all the same exceptions provided by the 2025 California Energy Code, as it is meant to exceed certain Energy Code provisions.
In the case of an alteration to an existing multifamily or nonresidential pool or spa, the same primary heating requirements are provided, along with exceptions.
However, if a local jurisdiction were to adopt these provisions of the CALGreen Code, replacing an existing gas pool heater with another one would not be an option as it is in the Energy Code.
The other difference is the inadequate solar access roof exception — it only applies to permanent spas in the Energy Code, but is applicable to both permanent spas and pools in the CALGreen Code.
Thanks to the PHTA/CPSA comments, the 2025 California Energy Code and CALGreen will allow for a more gradual move to the new requirements. The result will be significantly more flexibility for all aquatics industry professionals, minimized cost and time impact, and an easier compliance path.
