San Francisco Climate Zone & Energy Code
Climate Zone: CEC Climate Zone 3 (coastal marine). IECC Climate Zone 3C. San Francisco's marine climate is characterized by extremely mild temperatures year-round, persistent fog, and minimal temperature extremes. Cooling design is among the lowest in California at ~73°F; heating design is mild at ~42°F.
Energy Code & Manual J Requirement: California Title 24 Part 6 (2025 edition, effective January 1, 2026) plus San Francisco's local reach codes mandating all-electric new construction. ACCA Manual J required for residential HVAC sizing. SF Building Inspection enforces both state and local energy codes. Heat pump water heaters and space heating/cooling heat pumps are now essentially required for new SF construction.
Local Electric Utility: Pacific Gas & Electric (PG&E)
Building Department: San Francisco Department of Building Inspection (SFDBI)
Local Trade Association: ACCA California / ASHRAE Golden Gate Chapter / SMACNA Northern California