Is a Title 24 report required for every ADU type in California?

In almost every case, yes — if you are building a new ADU or converting existing space into a dwelling, California's energy code (Title 24, Part 6) applies, and the permit package needs a registered CF1R. The depth of the requirements changes with the project type, but a registered report is prepared for nearly every ADU.

Why an ADU triggers the requirement

An ADU is legally a dwelling unit — it has living, sleeping, cooking, and sanitation facilities — so it is treated like a residence for energy-code purposes, not like a shed or accessory structure. California's Building Energy Efficiency Standards apply to new dwelling units and to many alterations, which means the building department generally cannot issue your permit without the energy documentation in the submittal.

How scope changes by ADU type

• New detached ADUs face the most comprehensive requirements — full envelope, HVAC, water-heating, lighting, and potential solar provisions, with HERS verification of certain systems.
• New attached ADUs are also new conditioned space and are treated similarly to detached units for most measures.
• Garage and interior conversions are generally reviewed under alteration rules, which are typically narrower — solar usually does not apply, and insulation standards are triggered mainly where assemblies are actually altered — but a CF1R is still prepared and registered.

A quick self-check

1. Are you adding new conditioned floor area? → Report needed.
2. Are you converting an unconditioned space such as a garage or basement into living space? → Needed, under alteration rules.
3. Are you installing or replacing HVAC, a water heater, or substantial lighting? → Likely needed.
4. Is the work purely cosmetic — paint, flooring, cabinetry — with no energy systems touched? → Often not needed.

Think of the CF1R as the energy "passport" for your ADU: without it registered and submitted, the permit package is incomplete, and what the contractor installs later has to match what the document specifies.

Because the edge cases are sensitive to your jurisdiction, the applicable code cycle and local amendments vary — confirm with your local building department; the 2022 and 2025 code cycles are the ones most ADU owners deal with today, with the 2025 code applying to permit applications submitted on or after January 1, 2026. We prepare the registered CF1R as a +$240 add-on alongside your MEP plans — see California ADU requirements.