California has announced updates to its Energy Code for 2025, aiming to improve energy efficiency in new and renovated buildings across the state. The updated code is part of California’s Title 24 Building Standards Code and is designed to help lower consumer costs and reduce greenhouse gas emissions.
According to the California Energy Commission (CEC), these changes are expected to save $4.8 billion in energy costs over 30 years and cut greenhouse gas emissions by about 4 million metric tons, which is similar to the annual energy use of more than half a million homes. Builders will also have the option to adopt even higher efficiency standards through CALGreen, an additional part of the code that was updated alongside the 2025 Energy Code.
The CEC develops new codes every three years, considering feedback from the public, builders, and other stakeholders. These codes aim to keep up with technology advances and maximize cost savings and emission reductions over a building’s lifetime.
“Energy efficiency is the quiet workhorse of the clean energy transition. Efficiency reduces Californians’ bills, improves their health and comfort, and reduces strain on the electricity grid,” said CEC Commissioner Andrew McAllister. “When we build and upgrade homes to use less energy, California families save money, and communities get cleaner air and a more reliable electricity system.”
Compared with national standards for new homes, California’s updated code could allow residents to save nearly half on their energy bills. Many new homes in other states do not meet even current national model codes, making California’s requirements among the most stringent nationwide.
Key features of the 2025 update include encouraging heat pumps for heating air and water in single-family homes by setting building “energy budgets.” The code also updates HVAC requirements so residents can benefit from smart thermostats that adjust usage based on pricing information. Other measures increase wall and window efficiency.
For multifamily buildings, heat pumps are encouraged for space heating as well as water heating in certain low-rise units. The code requires electric-ready wiring for future installation of clean appliances, strengthens ventilation standards for better indoor air quality, expands access to electric vehicle charging infrastructure, and boosts insulation measures.
Businesses face encouragements toward using heat pumps in select new buildings. When existing rooftop HVAC systems reach end-of-life on commercial properties like stores or schools, replacements must be high-efficiency models such as heat pumps under alterations covered by this update. Commercial kitchens must be wired for easier future transitions to electric appliances; building envelope improvements are also required.
Projects involving repairs or reconstruction after damage from major wildfires in Los Angeles County during 2025 are temporarily exempted from some requirements—such as mandatory solar panels—but must still be ready for solar installations per Executive Order N-29-25.
“We are gratified that builders in California will be designing to the 2025 California Energy Code,” said CEC Building Standards Branch Manager Gypsy Achong. “Compliance with this update is the most affordable way to build a resilient and comfortable building for the future. This update does not mandate specific technologies or fuel types. We continued our long-standing tradition of figuring out what energy budget is pragmatically possible and then asking designers to meet that budget. We are delighted that this approach continues to affordably advance our state’s transition to 100% clean energy in buildings.”
California has been recognized nationally for its leadership in energy efficiency policy by topping the State Energy Efficiency Scorecard released annually by the American Council for an Energy-Efficient Economy—a nonprofit research group—for seven out of sixteen years since rankings began. In March 2025, it received top marks across all categories due partly to efforts supporting decarbonization goals in disadvantaged communities.
Over five decades, Californians have saved more than $200 billion through appliance and building efficiency standards—a figure projected to reach $300 billion by 2030—and last year alone saw $11 billion saved due largely to appliance standards that reduced carbon emissions at levels equivalent to taking dozens of gas power plants offline.
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About the California Energy Commission
The California Energy Commission is responsible for advancing state energy policy; promoting efficiency; certifying power plants; investing in innovation; developing renewables; transforming transportation; and preparing for emergencies.
