Chicago Climate Zone & Energy Code
Climate Zone: IECC Climate Zone 5A (cold-humid). Chicago's climate spans extreme winter cold (-4°F heating design, with occasional -20°F+ events), hot humid summers (91°F/74°F cooling design), and meaningful latent loads. Both heating and cooling drive equipment sizing substantially.
Energy Code & Manual J Requirement: Illinois Energy Conservation Code (IECC 2024 with Illinois amendments). ACCA Manual J required for residential HVAC permits. City of Chicago has its own extensive building code requirements alongside state energy code. Suburban Cook County and collar county municipalities administer their own permits.
Local Electric Utility: ComEd (Commonwealth Edison / Exelon)
Building Department: City of Chicago Department of Buildings
Local Trade Association: ACCA Illinois Chapter / ASHRAE Illinois Chapter / SMACNA Chicago