Is Title 24 required for ADUs?

Yes — a Title 24 energy compliance report is required for essentially every ADU type in California, though the compliance path differs by project. New and attached units follow new-construction rules, while garage conversions and JADUs typically follow the less-comprehensive alteration rules. The applicable code cycle and details change over time, so confirm current requirements with your local building department.

What Title 24 is

"Title 24" refers to the California Building Energy Efficiency Standards (Part 6 of the state building code). For your permit, the key document is the CF1R (Certificate of Compliance), which must be prepared in CEC-approved software and registered with an Energy Code Compliance Provider — building departments require the registered version, not just a PDF. During and after construction, the CF2R (installer certificate) and CF3R (HERS verification) follow, and the city won't issue a certificate of occupancy until the required CF3Rs are registered.

How the path varies by ADU type

What Title 24 controls in your design

The CF1R sets minimums that your MEP plans must match exactly, or the plans draw corrections:

• HVAC efficiency — the 2025 code makes heat pumps the prescriptive baseline for space conditioning.
• Water-heater efficiency — heat-pump water heaters are strongly favored.
• Insulation R-values and window U-factors, which depend on your specific climate zone (California has 16, determined by parcel address).
• Lighting power density and mandatory whole-building ventilation per ASHRAE 62.2.

Two of the most common Title 24 rejections are an unregistered CF1R and the wrong climate zone — both avoidable when the report is prepared correctly from the start.

What to expect during construction

Title 24 doesn't end at plan check. The compliance documents follow the build through to occupancy:

1. At permit: submit the registered CF1R with your plans.
2. During installation: each trade completes its CF2R certifying the installed equipment matches the CF1R.
3. Field verification: a CEC-certified HERS rater verifies items like refrigerant charge and ventilation airflow, then registers the CF3R.
4. Occupancy: the city holds the certificate of occupancy until the required CF3Rs are registered.

Planning for these steps up front — and choosing equipment that comfortably meets the CF1R — keeps the final inspection clean and prevents last-minute scrambles to swap out under-spec equipment.

Bundle it with your MEP plans

Because the CF1R and the MEP plans have to agree on equipment efficiencies, preparing them together prevents mismatches. We add a registered Title 24 report to your order for $240 — below the typical standalone fee — and coordinate it with your drawings so you can submit everything at once. See Title 24 Reports and the ADU Title 24 Guide for details. Energy code requirements change between cycles, so verify the current standards for your permit date.