2025 California Energy Code Updates: What Changed for ADUs?

California updates its Energy Code on a roughly three-year cycle, and the current version — the 2022 Energy Code — took effect January 1, 2023, and remains the active standard. Here's a practical look at what it changed for the residential and ADU projects most homeowners are dealing with.

The most talked-about change was the expansion of solar PV and battery storage requirements for new construction. Most new single-family homes and many low-rise multifamily buildings now need to include solar PV sized to the building's electrical demand, plus, in many cases, battery storage capacity — a significant shift from the prior code cycle where solar was required but battery storage was more of an optional compliance credit.

For ADUs specifically, the 2022 cycle clarified and in some cases simplified compliance paths for smaller accessory units, while maintaining the baseline requirement that all ADUs — regardless of size — need full energy compliance documentation. The code also sharpened requirements around electric-ready provisions, anticipating an eventual shift away from gas appliances even where gas remains permitted.

Electric vehicle charging infrastructure requirements expanded under this cycle as well. New construction and many major renovations now need to provide EV-charging-capable infrastructure (not necessarily a full charger, but the electrical capacity and conduit to support one), which factors into the overall electrical and energy planning for a project even though it's adjacent to the traditional envelope/HVAC focus of Title 24.

Heat pump technology continues to be incentivized over gas equipment across the update, both for space conditioning and water heating — heat pump systems generally have an easier time meeting efficiency targets under the current code than comparable gas equipment, which is shifting design defaults across the industry even where gas remains code-compliant.

For most remodel and addition projects that aren't large enough to trigger the more dramatic solar/battery requirements, the practical day-to-day experience of Title 24 compliance hasn't changed dramatically — but it's worth confirming with your energy consultant that your project's specific report reflects current 2022 code requirements rather than calculations carried over from an earlier cycle.