We prepare the Title 24 energy report (CF1R) your city needs to permit an ADU in California. Each report is built for the 2025 Energy Code, which applies to permit applications submitted on or after January 1, 2026.
What kind of ADU are you building?
The Energy Code treats ADUs in three different ways. We start by putting yours in the right category, because it changes almost everything else.
| ADU type | Energy Code category | What it means |
|---|---|---|
| New detached ADU | New construction | Same rules as a new single-family home, including solar PV in most cases |
| Attached ADU | Addition | Section 150.2(a) addition rules; no solar requirement |
| Garage or storage conversion | Addition | Also an addition, attached or detached |
| Conversion of already-conditioned space | Alteration | Rules apply to the parts you change |
See our full guide: Title 24 for ADUs.
What is in an ADU Title 24 report?
- The registered Certificate of Compliance (CF1R), signed in CHEERS when your project needs ECC testing.
- Sheets sized to drop into your plan set.
- Solar PV sizing when the ADU is a new detached unit.
- The list of items an ECC (HERS) rater must test.
- A one-page list of the minimum ratings your water heater, heat pump, windows, roof, fans and kitchen hood must meet, so your contractor can pick parts that match.
What ADU rules come up most often?
These are the ones the CEC's 2025 ADU FAQ addresses directly:
- Solar on detached ADUs. New modules can be added to the main house's existing system, on the same lot. The existing system alone does not count.
- Battery-ready. New detached ADUs must meet Section 150.0(s), unless the ADU's service is 125 amps or less.
- Small-ADU water heating. Units of 500 square feet or less may use an electric water heater with point-of-use piping instead of a heat pump water heater.
- QII. ADU additions of 700 square feet or less are exempt from the prescriptive quality insulation inspection.
- Mini-splits. Allowed. They may trigger ECC testing, including refrigerant charge in every climate zone.
- Kitchen hoods. Vented hoods need their certification, airflow and sone rating verified by an ECC rater.
Who signs the report?
The person responsible for the design signs the CF1R as the responsible designer. We sign as the documentation author. If your project is a wood-framed home up to two stories that does not need a licensed designer, the builder may sign as the responsible designer. CHEERS does not charge to sign a CF1R.
Later, each installer signs an installation form (CF2R). If testing is required, an independent ECC rater signs the verification forms (CF3R). See CF1R, CF2R and CF3R explained.
What do I send to get started?
- Floor plan with dimensions
- Elevations
- Window and door sizes
- Wall section and roof type, if drawn
- Heating, cooling and water heating choices, if known
If you have not picked equipment yet, your contractor can use the minimum ratings in your report to choose matching parts. We do not recommend products or brands.
Which climate zone is my ADU in?
Requirements change by climate zone. California has 16. See California climate zones to look yours up.
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Frequently asked questions
Does every ADU need a Title 24 report?
A new detached ADU, an attached ADU and a garage conversion all fall under the Energy Code and need a Certificate of Compliance (CF1R). An ADU built inside space that is already heated or cooled is an alteration, so the rules apply to the parts you change.
Will my detached ADU need solar?
Usually. The CEC says a newly constructed detached ADU must have newly installed solar PV under Section 150.1(c)14 unless an exception applies. Attached ADUs are additions and do not need solar.
Will I need an ECC (HERS) rater?
Most new ADUs with a mini-split do. Common tests are refrigerant charge, verified efficiency ratings and capacity, ventilation fan airflow and the kitchen hood's ratings. Your CF1R lists the exact items.
What do you need from me?
Plans as a PDF: a dimensioned floor plan, elevations and a window and door list. A wall section and your heating, cooling and water heating choices help.