California has announced updates to its Energy Code, which will take effect in 2025. The new standards are part of Title 24 of the Building Standards Code and aim to improve energy efficiency in buildings across the state. According to the California Energy Commission (CEC), these changes are expected to save consumers an estimated $4.8 billion in energy costs over 30 years and reduce greenhouse gas emissions by about 4 million metric tons, which is similar to the annual energy use of more than half a million homes.
The updated code encourages the use of heat pumps for space and water heating and includes measures to shift energy consumption away from peak demand periods. It also allows builders to voluntarily adopt higher efficiency standards through CALGreen, another part of the code that was updated alongside the main changes.
The CEC develops and approves new building codes every three years, considering input from various stakeholders including the public and builders. The goal is to incorporate technological advances and ensure cost savings and emission reductions over each 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, homes built under California’s 2025 Energy Code will see nearly half lower energy bills. Many new homes elsewhere in the U.S. do not meet even current national model codes, making California’s requirements among the most stringent for residential efficiency.
Key changes for single-family homes include establishing energy use budgets that encourage heat pumps for heating, cooling, and water heating; updating HVAC controls so residents can benefit from lower-cost rate periods via smart thermostats; and increasing wall and window efficiency.
For multifamily residences, there are similar pushes for heat pump adoption as well as electric-ready requirements for easier installation of electric appliances in low-rise buildings. Ventilation standards have been strengthened to improve indoor air quality, while access to electric vehicle charging has been expanded through dedicated circuits and parking spaces with chargers.
Nonresidential buildings such as businesses will be encouraged to use heat pumps for heating and cooling in certain cases. For alterations only, some rooftop HVAC systems must be replaced with high-efficiency models at end-of-life on properties like stores or schools. Electric-ready requirements have also been established for commercial kitchens.
An executive order temporarily suspends parts of these updates for projects repairing or replacing structures damaged by wildfires in Los Angeles County during 2025; those projects do not need to comply with solar or battery storage rules but must still be solar-ready.
“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.”
In March 2025, California was ranked first nationally by the American Council for an Energy-Efficient Economy (ACEEE) on its State Energy Efficiency Scorecard—its seventh time leading since rankings began sixteen years ago. The state received top marks across all categories due partly to its efforts supporting equitable decarbonization goals such as installing heat pumps in low-income communities.
Over fifty years, Californians have saved more than $200 billion thanks to appliance and building efficiency standards—a figure projected by officials to reach $300 billion by 2030. In just one year recently analyzed, appliance standards alone saved residents over $11 billion—equivalent in carbon reduction terms to shutting down sixty gas power plants—with significant savings attributed specifically to lighting ($4.7 billion), televisions/displays ($2 billion), battery chargers ($1.64 billion), computers ($593 million), and monitors ($89 million).
The CEC remains responsible for advancing state policy on energy issues including planning, innovation investment, renewable development, transportation transformation, emergency preparedness, plant certification, as well as promoting overall efficiency.
