IECC 2021 · PNNL
Utah climate zones
Utah’s 29 counties fall in 3 IECC 2021 climate zones: 3B (1), 5B (21), 6B (7).
Zone 3B: warm-dry
Attic target R49 (ENERGY STAR)Washington County (Hot-dry)
Zone 5B: cool-dry
Attic target R60 (ENERGY STAR)Beaver County (Cold) · Box Elder County (Cold) · Cache County (Cold) · Carbon County (Cold) · Davis County (Cold) · Emery County (Cold) · Garfield County (Cold) · Grand County (Cold) · Iron County (Cold) · Juab County (Cold) · Kane County (Cold) · Millard County (Cold) · Piute County (Cold) · Salt Lake County (Cold) · San Juan County (Cold) · Sanpete County (Cold) · Sevier County (Cold) · Tooele County (Cold) · Utah County (Cold) · Wayne County (Cold) · Weber County (Cold)
Zone 6B: cold-dry
Attic target R60 (ENERGY STAR)Daggett County (Cold) · Duchesne County (Cold) · Morgan County (Cold) · Rich County (Cold) · Summit County (Cold) · Uintah County (Cold) · Wasatch County (Cold)