New Haven Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 5A (cold-humid). New Haven's Long Island Sound location produces slightly milder winters (9°F heating design) than inland Connecticut, with persistent coastal humidity increasing latent cooling loads through the summer.

Energy Code & Manual J Requirement: Connecticut State Building Code (IECC 2021 basis). ACCA Manual J required for residential HVAC permits across all New Haven County jurisdictions.

Local Electric Utility: United Illuminating (UI / Avangrid)

Building Department: City of New Haven Building Inspection Services

Local Trade Association: ACCA New England / ASHRAE Connecticut Chapter