Sunnyvale Climate Zone & Energy Code

Climate Zone: CEC Climate Zone 4 (South Bay / Santa Clara Valley). IECC Climate Zone 3C. Sunnyvale's South Bay position produces warmer summers than coastal San Francisco — 92°F cooling design — while maintaining milder conditions than Sacramento. Heating design of 32°F reflects the Bay Area's mild winters.

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 Sunnyvale and Santa Clara County jurisdictions enforce Title 24. Many Silicon Valley cities have adopted or are adopting all-electric reach codes for new construction.

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

Building Department: City of Sunnyvale Community Development Department

Local Trade Association: ACCA California / ASHRAE Silicon Valley Chapter