California took another big step forward this week toward a future of clean, efficient buildings with its finalization of the 2025 Title 24 Building Energy Standards (the “Building Code”). Under the updated Building Code, starting in 2026, the vast majority of new homes in the Golden State will be built without fossil fuel connections and many new and existing commercial buildings will be encouraged to adopt all-electric heating.
This marks another important milestone in California’s clean energy journey. Just a few years ago, California was adding more new gas customers than anywhere in the nation besides Texas. Now, the state is steadily steering away from fossil fuel dependence, paving the way for emissions-free heating and cooling across its new housing stock.
Building on the green foundation laid in 2021, this latest code takes several significant steps forward for climate-friendly homes and buildings:
- It enhances requirements for new homes to strongly encourage heat pumps for both space and water heating, rather than just one end-use.
- It includes provisions to encourage the replacement of gas rooftop units on commercial buildings with heat pumps when they burn out. These units account for roughly 25% of commercial HVAC units in California.
- It expands on existing requirements for new commercial buildings by encouraging heat pump space heating to larger systems in schools and office buildings.
Heat pumps are two-for-one climate winners—providing efficient cooling and zero-emission heating that can displace dirty fossil fuel furnaces with a single appliance. A heat pump installed in California today will cut emissions from space heating by 93% over the lifetime of the equipment compared to a gas furnace.
The Missing Piece: Tackling Pollution from Existing Homes
However, there’s still work to be done: as essential as stemming the tide of new fossil fuel homes is, California needs to do much more to tackle pollution from existing buildings to hit our 2030 climate targets. And that’s where the new code falls short.
The newly-adopted code scrapped a critical provision included in a previous draft that would have encouraged households statewide to install two-way heat pumps when replacing old air conditioning (AC) units. Instead, it punts that responsibility to individual local governments to push for heat pump swaps when existing ACs burn out.
For many homeowners, installing a two-way heat pump when their existing AC stops working is a remarkably simple switch. These dual systems are essentially ACs with one extra part—a reversing valve that allows them to provide efficient heating too.
Most installations follow the same process as traditional cooling units, but open the door to using clean electricity, instead of burning fossil fuels, to keep homes warm. It’s a common-sense climate solution in an affordable package.
Avoiding the installation of one-way ACs now will also save families money and hassle down the road, as the California Air Resource Board (CARB) moves toward zero-emissions appliances standards in 2030 which will require heat pumps to be installed instead of polluting gas furnaces. This rule is already in place in the Bay Area where, starting in 2029, when a gas furnace burns out it will need to be replaced with a heat pump thanks to approved air quality regulations.
While the building code represents climate progress, California has farther to go on its overall heat pump goals. Governor Newsom aims for 6 million heat pumps installed statewide by 2030, but as of last fall, that number hovered around just 1.5 million across 800,000 homes.
But there’s hope on the horizon. While a statewide policy is needed, supporting local governments in adopting language to encourage heat pump installations is a solid first step.
The upcoming code adoption is a pivotal opportunity for California to boost its heat pump pathway to a decarbonized future. Strong statewide standards can provide the policy certainty to ramp up heat pump supply chains, boost consumer adoption, and mainstream these affordable climate solutions in time to meet our fast-approaching 2030 climate goals.
