When planning a new heated pool or spa in California, it is important to understand how the 2025 California Energy Code, Title 24, Part 6 may affect your project.
What Is Title 24, Part 6?
Title 24, Part 6 is California’s Energy Code. Its purpose is to specify building requirements that do the following:
- Reduce electricity and gas energy use
- Lower long-term utility costs
- Decrease greenhouse gas emissions
- Improve building and equipment efficiency
- Help manage energy demand on California’s power grid
For new pool and spa owners, the updated code affects how new pools and spas may be designed and heated.
How Does Title 24 Affect Pool and Spa Heating?
Gas heaters have historically been a common choice for pool and spa heating, but under the updated code, they generally cannot be used as the primary heating source. Gas heaters are limited to supplemental or backup use as part of a compliant system design. As with most rules, there are very limited exceptions that only apply to very few pool and spa users.
Approved Title 24 Pool and Spa Heating Options
For most new heated pool and spa projects permitted after January 1, 2026, the primary heating system must be one of the following options:
Solar Pool Heating
Solar pool heating must be sized at:
- 60% or more of the pool or spa surface area for single-family homes
- 65% or more of the pool or spa surface area for multifamily or nonresidential projects
For example, a single-family pool that is 15 ft. × 30 ft. has 450 sq. ft. of surface area.
Using the 60% sizing requirement:
450 × 60% = 270 sq. ft.
Therefore, for this example approximately 270 sq. ft. of solar pool heating collector area would be required, either mounted on the ground or above ground on a roof or structure.
Heat Pump Pool Heater
A heat pump pool heater may be used as the primary heating system if it is properly sized under the code’s requirements. In simple terms, the heat pump must be large enough to achieve a 10°F temperature rise in no more than 17.5 hours. The cost of the heat pump is therefore related to the size of the pool involved. The greater the pool capacity, the greater the cost of the heat pump. In this sense, the surface area requirement for solar pool heating and the heat pump temperature to time ratio are the method the code uses to guarantee that the primary heating system is actually able to do the job effectively.
Renewable or Recovered Energy System
Another option is a system that receives at least 60% of its annual heating energy from on-site renewable or recovered energy. This is a catch-all category for systems powered by wind, recovered gases, or other means. An anaerobic digester built on a dairy farm might be one example.
Solar + Heat Pump Combination
A solar pool heating system may also be combined with a heat pump pool heater, as long as the system does not include an additional supplementary heater. In effect, the solar pool heater is the primary heater and the heat pump is now the backup or supplementary heater. This would be maximum heating for minimum greenhouse gases.
Other Approved Systems
The code may also allow another California Energy Commission-approved system if it uses no more energy than the listed options. It would undoubtedly require an engineer’s approval to guarantee the merits of any conceived alternative. Loopholes like this often exist simply to allow for unforeseen future technologies.
Of course, requirements can vary by project and local jurisdiction, so it is recommended that homeowners confirm details with their reputable pool contractor, solar installer, and local building department. Solaron is here to help you navigate this process successfully.
Why Solar Pool Heating Makes Sense
Solar pool heating is one of the most practical options for many California homeowners. It uses the sun to help heat your pool water, offers very low operating costs, and helps reduce reliance on gas or electricity. For homeowners with good sun exposure and available roof or ground space, solar pool heating is an efficient way to help meet the updated Title 24 requirements while extending the swimming season. So, if you are a homeowner planning a new heated pool or spa in California, contact Solaron. We provide a free solar analysis to determine whether solar pool heating is the right solution for your project. Contact us by phone or online.