Rockford Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 6A (cold-humid). Rockford's northern Illinois location produces colder winters (-8°F heating design) than Chicago and slightly cooler summers. Both heating and cooling loads are significant, with a strong emphasis on heating system reliability.

Energy Code & Manual J Requirement: Illinois Energy Conservation Code (IECC 2024). ACCA Manual J required for residential HVAC permits in Winnebago County and surrounding northern Illinois jurisdictions.

Local Electric Utility: ComEd (Commonwealth Edison / Exelon)

Building Department: City of Rockford Building & Zoning Department

Local Trade Association: ACCA Illinois Chapter