California's 2025 Title 24 Code Takes Effect, Expanding Heat Pump and Electric-Ready Mandates

California's 2025 Title 24 Building Energy Efficiency Standards took effect January 1, 2026, and the residential and commercial sections both got a significant shove toward electrification. Heat pumps are now the prescriptive baseline for space and water heating in most new construction. End-of-life rooftop units on existing commercial buildings have to be replaced with heat pump systems. The California Energy Commission estimates $4.8 billion in statewide energy savings over the life of the code.

That last number is a CEC estimate. The actual installer impact is already showing up in permit applications.

What the Code Actually Requires

For new single-family homes and multifamily buildings, Title 24 2025 sets a heat pump baseline for both space heating and water heating. Gas options are still permissible under the performance pathway, but the trade-offs on envelope, mechanical, and solar requirements make gas the more expensive route in most climate zones. In practice, builders are defaulting to heat pumps.

The commercial side is more aggressive. Title 24 2025 requires heat pump replacement for end-of-life rooftop units in most retail, school, and office buildings. That affects hundreds of thousands of existing rooftops statewide, not just new construction. Commercial kitchens and multifamily buildings must also include electric-ready provisions, which typically means stubbed conduit and panel capacity for future electric equipment swaps.

The code applies to permits filed on or after January 1. Projects in permit review before that date run under the 2022 standards.

Installer Impact

For residential installers, the big shift is water heating. Heat pump water heaters, which had been a niche option in most of California, are now the default on new construction. Installers who don't already stock and service A.O. Smith, Rheem, and Bradford White heat pump water heaters are about to get very busy catching up.

For commercial HVAC contractors, the rooftop retrofit mandate is a long tail of work. Most commercial rooftop units have 15-to-20-year service lives. As existing fleets age out, those replacements are now heat pumps by default, which means bigger electrical upgrades, more roof penetrations for refrigerant lines in some configurations, and more structural load analysis.

Plan checkers in Los Angeles, San Francisco, and San Diego are already flagging non-compliant permit applications. Contractors we spoke with in March said they're seeing two-to-four-week review delays as local jurisdictions absorb the new standards.

SB 282, working its way through the state legislature, would standardize heat pump permitting across California jurisdictions to reduce that delay. It hasn't passed yet.

For related coverage, see our analysis of DOE 2027 efficiency standards and the 2026 EPA refrigerant transition update.