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2025 Cycle

Swimming Pool and Spa Heating

Multifamily
Nonresidential
Single Family
Domestic Hot Water

Proposal Description

Background

Solar thermal harnesses the sun’s energy to generate heat for commercial and residential applications such as space heating, air conditioning, water heating, industrial process heat, drying, distillation and desalination, and even electrical power generation. There are several types of collectors that can be used for solar thermal systems, such as unglazed, transpired, flat-plate, evacuated tubes or concentrating collectors. In the case of swimming pool heating, unglazed collectors are often used due to their efficiency and affordability.

As one of the simplest and least expensive forms of solar thermal technology, unglazed collectors do not have a glass covering or “glazing” on the collector box and often use black plastic panels of aligned water tubes mounted on a roof or other support structure to absorb sunlight. A water pump circulates pool water directly through the water tubes, transferring energy to the water. The pump returns the water to the pool at a higher temperature, between 95 °F and 100 °F. Although primarily for pool heating, collectors can also preheat large volumes of water for other commercial and industrial applications.

Proposed Code Change

The proposed code change would require solar thermal pool and spa (except portable electric spas) heating systems, HPPH with certain COP, sizing and controls criteria, or on-site renewable energy or site recovered energy in nonresidential, multifamily, and newly constructed single-family buildings with heated swimming pools and spas. The surface area of the solar collectors installed would be equal to or greater than 65 percent of the surface area of the pool for residential pools and 60 percent of the surface area of the pool for multifamily and nonresidential pools. At least 60 percent of the annual heating energy would be required to come from on-site renewable energy or site recovered energy as an option.

This proposed measure would apply to newly constructed pools and existing pools installing a new gas or electric heater. Single family residential pools with an existing pool heater can replace with the same technology. Acceptance testing would not be required for this measure.

While we are modifying the requirements for pools and spas, the Statewide CASE Team will also explore opportunities to update language as needed based on advances in technology and standard design practices, and existing federal and state regulations applicable to pool heating products. The Statewide CASE Team is also proposing a cleanup of section 150.0(p) to harmonize Title 24, Part 6, with provisions in the federal regulations on dedicated-purpose pool pumps.

The CASE Report report focuses on analysis and cost effectiveness of the solar thermal option for compliance. This report does not include analysis on the recovered energy option as it is an existing provision within Section 110.4(a)4 under the exception for prohibiting electric resistance heating.

Relevant Documents

CASE Report

Round Two Utility-Sponsored Stakeholder Meeting Materials

Round One Utility-Sponsored Stakeholder Meeting Materials

Provide Feedback

Submit feedback and view the Energy Commission's proceedings and available proposed code language by visiting their 2025 Building Energy Efficiency Standards page.

This measure page will be updated as the 2025 code cycle progresses. For questions or suggestions, email [email protected]. Please include the measure name in the subject line.

Give Us Your Feedback

The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.

  • Use the form above to provide feedback on this measure.