Ann Arbor Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 5A (cold-humid). Ann Arbor's SE Michigan position produces cold winters (4°F heating design) and hot, humid summers (90°F/73°F cooling design). Lake influence from both Erie and Michigan moderates extremes somewhat compared to northern Michigan communities.

Energy Code & Manual J Requirement: Michigan Residential Energy Code (aligned with IECC 2021). ACCA Manual J required for HVAC permits in Washtenaw County and all Ann Arbor area jurisdictions.

Local Electric Utility: DTE Energy

Building Department: City of Ann Arbor Building & Rental Inspections

Local Trade Association: ACCA Michigan Chapter / ASHRAE Michigan Chapter