Boulder Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 5B (cold semi-arid). Boulder's Front Range foothill position at 5,430' produces cold winters (-3°F heating design) and warm summers (93°F cooling design). Mountain proximity drives frequent Chinook events and high wind exposure that affects infiltration calculations significantly.

Energy Code & Manual J Requirement: Colorado IECC 2021 plus Boulder's local reach code requirements for energy efficiency and electrification. ACCA Manual J required for residential HVAC permits. Boulder has some of the most aggressive local energy requirements in Colorado.

Local Electric Utility: Xcel Energy

Building Department: City of Boulder Community Planning & Sustainability

Local Trade Association: ACCA Rocky Mountain Chapter / ASHRAE Rocky Mountain Chapter