The Bay Area’s mild coastal-influenced climate and high housing demand drive steady ADU, residential, and multifamily energy-compliance work.
Title 24 Across the Bay Area
High land costs make the Bay Area a strong market for adding homes to existing lots: backyard ADUs, garage conversions, in-law units and small multifamily buildings. Much of the housing stock is older, so alterations such as window replacements and heat pump conversions are also common. Each city and county has its own building department, but the energy code and compliance forms are the same statewide — a CF1R for homes and ADUs, and a multifamily report for multi-unit buildings.
Bay Area Microclimates and Climate Zones
Few regions change climate as quickly over a few miles. Neighborhoods exposed to ocean fog stay cool most of the year, so heating matters more than cooling. Valleys behind the coastal hills get warmer summers, and cooling and window orientation start to count.
- Bayside — San Francisco, Oakland, Berkeley and Fremont are in Climate Zone 3.
- South Bay — San Jose and Santa Clara are in Climate Zone 4.
- North Bay — Santa Rosa, Napa, Petaluma and San Rafael are in Climate Zone 2.
- East Bay inland valleys — Walnut Creek and Concord are in Climate Zone 12, with noticeably hotter summers.
Zone lines do not follow city limits, so the report always uses the zone for your project address and ZIP code. See the climate zone map.
Common Bay Area Projects
- Backyard ADUs and JADUs — see ADU Title 24 reports
- Garage conversions into living space — see the garage conversion service
- Duplexes and small apartment buildings on infill lots
- Heat pump conversions and window replacements in older homes — see the HVAC replacement service
We also serve cities including San Mateo, Hayward and Sunnyvale. For the wider region, see Northern California Title 24.
Frequently Asked Questions
Do Bay Area cities add their own energy rules?
Some Bay Area jurisdictions adopt local amendments or reach codes on top of the state code. Tell us if your building department has given you a local checklist.
Does a mild climate mean my ADU is exempt?
No. A new ADU still needs Title 24 documentation for the permit, even where the climate makes compliance easier.
