Hillsboro Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 4C (marine Pacific Northwest). Hillsboro's Tualatin Valley position is slightly warmer than coastal Portland — 91°F cooling design and 22°F heating design. Marine climate produces mild, wet winters and warm but not extreme summers.

Energy Code & Manual J Requirement: Oregon Energy Code (IECC 2021). ACCA Manual J required for residential HVAC permits in Washington County and Hillsboro jurisdictions.

Local Electric Utility: Pacific Power (PacifiCorp)

Building Department: City of Hillsboro Community Development Department

Local Trade Association: PHCC Oregon