Title 24 for ADUs: what actually triggers compliance

California's Title 24 Part 6 Energy Code is enforced on every new ADU. The 2022 code (in effect since Jan 1, 2023) made heat pumps the prescriptive default. The 2025 update, effective Jan 1, 2026, tightens envelope requirements and pushes solar-ready provisions further. This guide covers what triggers compliance and what an LADBS plan checker actually looks for — and how the answer reshapes your utility connection plan.

Prescriptive vs performance path

There are two routes to compliance. The prescriptive path is a checklist of minimum components (R-values, U-factors, equipment efficiencies). The performance path runs an energy model in CBECC-Res and shows the design beats a code-defined baseline. Most detached ADUs use the prescriptive path; attached ADUs and conversions usually need performance modeling — see detached vs attached vs conversion for the structural context.

Heat pumps are the new default

Under the 2022 code, gas furnaces and gas water heaters are still legal but trigger compliance penalties on the energy budget. The path of least resistance is a heat pump space heater (mini-split or central) and a heat pump water heater. The ENERGY STAR cold-climate heat pump list is a good starting point — though LA basically never needs cold-climate models.

Envelope requirements at a glance

• —Walls: R-21 cavity + R-5 continuous insulation in CZ8/9 (covers most of LA).
• —Roof/ceiling: R-38 cavity for vented attics, R-30 + cool roof for unvented.
• —Slab edge: R-7 to a depth of 16 inches.
• —Windows: U-factor ≤ 0.30, SHGC ≤ 0.23 (west and south orientations).
• —Air leakage: blower-door tested at ≤ 5 ACH50.

Solar-ready and EV-ready

ADUs detached from the primary dwelling are required to comply with solar-ready provisions: a clear roof area facing within 110° of true south. ADUs are exempt from the actual PV requirement that applies to new single-family homes — but if the primary dwelling triggers it, an LADBS plan checker may ask. EV charging: a single 240V outlet in an accessible location is the minimum for any new ADU with a parking space.

The CF1R signoff

Every Title 24 submittal needs a Certificate of Compliance (CF1R) signed by a Certified Energy Analyst. This is the document LADBS stamps. Plan check rejects almost always trace back to a CF1R that doesn't match the architectural drawings — windows on the floor plan that aren't on the CF1R, or HVAC equipment that isn't listed on the CEC Appliance Database. The LA permitting rules cover what else has to land in the intake packet alongside it.