Alhambra is in California climate zone 9, and its Building Division takes plan check applications through the city's Permit Portal, with plans submitted online through ePlan Check. We prepare the Title 24 report (CF1R) as PDF sheets ready to upload with your plans.
What climate zone is Alhambra in?
Climate zone 9. On the California Energy Commission's ZIP code list, all Alhambra ZIP codes are zone 9: 91801, 91802, 91803 and 91804.
Who reviews building plans in Alhambra?
The Building Division of the Community Development Department. The city says the Division "provides plan review and construction inspection services."
How do I submit plans in Alhambra?
Online. The Building Division's page says:
To apply for Building plan check and permits, please visit the Permit Portal...
The same page says to "Submit plans for ePlan check online." Inspections can also be requested through the Permit Portal.
Include the registered CF1R in the plan set you upload.
Does Alhambra have ADU guidance?
Yes. The Building Division publishes Accessory Dwelling Units Guidelines. The city describes them as guidelines "to applicants interested in building an Accessory Dwelling Unit (ADU)." Read them before your designer finishes the plans, so the energy report matches the final design.
What will my Alhambra ADU's report need?
Under the 2025 Energy Code, the type of ADU sets the rules:
- New detached ADU: treated as a new home. It usually needs new solar PV, and the main house's existing system alone does not count. New modules can be added to that system on the same lot.
- Attached ADU or garage conversion: an addition. No solar required. For a garage with 2x6 walls, R-21 cavity insulation meets the prescriptive rule without removing siding.
- Conversion of already-conditioned space: an alteration. The rules apply to what you change, like a new water heater or mini-split.
In climate zone 9:
- Prescriptive ceiling insulation for additions is R-38.
- A radiant barrier is a prescriptive requirement for additions (not for cathedral ceilings).
- The maximum window U-factor for additions and alterations is 0.30.
- Cool roof rules for steep-sloped roofs on additions do not apply. They cover zones 10 through 15.
See Title 24 for ADUs and garage conversions.
Will I need an ECC (HERS) rater?
Most new ADUs with a mini-split do. Refrigerant charge verification is required for new heat pumps in every zone, and for new air conditioners in zone 9. See ECC rater testing for ADUs.
Need a report for an Alhambra project? See our flat prices.
Frequently asked questions
What climate zone is Alhambra in?
Climate zone 9. Alhambra's ZIP codes (91801, 91802, 91803 and 91804) are all zone 9 on the California Energy Commission's ZIP code list.
How do I apply for plan check in Alhambra?
The Building Division's page says to apply for building plan check and permits through the city's Permit Portal, and to submit plans online through ePlan Check.
Does Alhambra have ADU guidance?
Yes. The Building Division publishes Accessory Dwelling Units Guidelines for applicants planning an ADU.
Related
Sources
- energy.ca.gov/programs-and-topics/programs/building-energy-efficiency-standards/climate-zone-tool-maps-and
- energy.ca.gov/sites/default/files/2020-04/BuildingClimateZonesByZIPCode_ada.xlsx
- alhambraca.gov/192/Building-Division
- alhambraca.gov/671/Accessory-Dwelling-Units-Guidelines
- energy.ca.gov/programs-and-topics/programs/building-energy-efficiency-standards/energy-code-support-center-6/2025
- energy.ca.gov/filebrowser/download/8641?fid=8641