Title 24 History
Snapshot Now
California Title 24 has grown from a response to the 1970s energy crisis into one of the most influential building energy codes in the country. Today, the current statewide standard is California’s 2025 Energy Code, effective for permit applications submitted on or after January 1, 2026. It expands heat pump use, encourages electric-ready construction, and strengthens ventilation requirements. Compliance is supported by approved software, permits, and field verification tools, while enforced primarily by local building departments.
Recent History
Before that, the 2022 code cycle pushed California further toward electrification and resilience, adding stronger electric-ready provisions, encouraging efficient heat pumps, and expanding solar and battery storage requirements. The 2019 cycle was the landmark update that brought solar photovoltaic requirements to most new low-rise homes. Earlier cycles in 2016 and 2013 steadily improved building envelopes, lighting, water heating, controls, and ventilation, while the 2005 era introduced Time Dependent Valuation, changing how California measured the value of energy savings by accounting for when those savings occur.
The beginning
The roots of Title 24 go back to 1974, when California passed the Warren-Alquist Act after the energy crisis of the early 1970s. That law created the California Energy Commission and established the authority to develop building energy standards. The first standards were created in the mid-1970s and were in effect by 1978, beginning a code history that has continued through regular three-year updates ever since.