California’s energy code, designed to reduce unnecessary and wasteful energy consumption in new and existing buildings, is updated every three years by the California Energy Commission (CEC). The latest Building Energy Efficiency Standards—Title 24, Part 6 of the Building Standards Code—went into effect in January 2023.

Enforced by local building departments through the permit application process, Title 24 is California’s unique code developed in-state. The latest changes are considered necessary because, according to the CEC’s 2022 Building Energy Efficiency Standards Summary, residential and nonresidential buildings are responsible for nearly 70% of the state’s electricity use and 25% of California’s greenhouse gas (GHG) emissions. To underscore the gravitas of the situation, a Harvard University study cited burning gas as the leading cause of premature death in 19 states and claims that outdoor air pollution from burning gas in buildings cost California $2.3 billion in 2017.

The 2022 changes are expected to increase on-site renewable energy and electric load flexibility, and to reduce emissions and air pollution from new construction.

In addition to several changes for nonresidential buildings, the updated codes also affect residential buildings. Chief among the changes affecting single-family homes is a requirement making heat pumps the baseline energy technology for either water or space heating.

Under the new code, at least one appliance for heating in the home must be powered by electricity instead of gas. In anticipation of widespread expansion of laws prohibiting gas appliances, the new code includes an electric-ready requirement for heating, cooking and clothes drying. When a gas water heater is installed, electrical infrastructure and space for future heat pump water heater installation must be provided. This is a first-in-the-nation step and is intended to reduce energy consumption and GHG emissions.

Under the new code, ventilation standards have been strengthened. Vented kitchen range hood ventilation rates are based on space and fuel type. Heat and energy recovery ventilation systems must carry a Home Energy Rating System verified fan efficacy of 1W/cfm.

Another update imposes new energy storage system-ready requirements for low-rise multifamily buildings, with space for future installation of a transfer switch or system isolation equipment. It also includes a requirement for registration of new low-rise multifamily compliance documentation, giving local authorities jurisdiction to avoid permitting delays.

Additional changes to the code include requirements regarding panelboards in single-family and multifamily buildings, expanded standards for photovoltaics and battery storage and new energy design rating metrics based on the energy source.