Climate Zone
A climate zone is a building-code classification of how cold or hot a location is, used to set prescriptive insulation, glazing, and ventilation requirements. The IECC (International Energy Conservation Code) divides the United States into 8 numbered zones (1 = very hot Florida/Hawaii, 8 = arctic Alaska) plus moisture suffixes A (humid), B (dry), and C (marine). Climate zone determines the minimum R-values, U-factors, and ACH50 targets for new construction in each county.