Hayward Climate Zone & Energy Code

Climate Zone: CEC Climate Zone 3 (south Bay Area / Alameda County). IECC Climate Zone 3C. Hayward's Bay shoreline position provides marine moderation — 80°F cooling design and 34°F heating design — though the Hayward Hills to the east are warmer and more exposed to inland conditions.

Energy Code & Manual J Requirement: California Title 24 Part 6 (2025 edition, effective January 1, 2026). ACCA Manual J required for residential HVAC sizing. All Hayward and Alameda County jurisdictions enforce Title 24. Multiple Alameda County cities have adopted electrification reach codes.

Local Electric Utility: Pacific Gas & Electric (PG&E)

Building Department: City of Hayward Building Division

Local Trade Association: ACCA California / ASHRAE East Bay Chapter