Updates to the recently adopted 2025 California Energy Code (Title 24, Part 6) are being submitted by the California Statewide Codes and Standards Enhancement Team to the California Building Standards Commission in December. These new requirements or upgrades to existing requirements are intended to save energy costs, reduce greenhouse gas emissions (GHG) and make buildings more climate resilient. If approved, they would go into effect Jan. 1, 2026, to give contractors time to make adjustments.

Updates include:

• High-performance windows for single-family homes, with lower mandatory and prescriptive U-factor requirements
• Improved framed wall construction for single-family homes, with lower mandatory U-factor requirements
• Defined prescriptive pathway for cathedral ceilings in single-family homes
• Promote optimal performance of heat pump water heaters through mandatory requirements for adequate ventilation for all building types
• Promote optimal performance of heat pump space heaters through the following mandatory measures (unless noted as prescriptive):
• Sizing and equipment selection requirements to ensure that heat pump systems can meet designed heating loads without supplementary electric resistance or gas heating
• Establishing maximum allowable capacities for supplementary heating systems and controls that limit the operation to times of cold outdoor air temperatures
• Controlling configuration requirements for timer-based defrost systems
• Functional testing to ensure that third-party thermostats are capable of modulating compressor speed when controlling variable-speed systems
• Expanding prescriptive third-party verification of accurate refrigerant charge for heat pumps to all climate zones

Every three years, the CEC updates and adopts building standards that reduce wasteful, inefficient or unnecessary energy consumption and reduce greenhouse gas emissions. Homes and businesses consume nearly 70% of California’s electricity and are responsible for about 25% of the state’s GHG emissions. Updates ensure the energy code is in alignment with the state’s goals for decarbonization by increasing energy efficiency and demand flexibility, as well as the recent application of heat pump technology.