Ohio climate zones
Ohio’s 88 counties fall in 2 IECC 2021 climate zones: 4A (24), 5A (64).
Zone 4A: mixed-humid
Attic target R60 (ENERGY STAR)Adams County (Mixed-humid) · Athens County (Mixed-humid) · Brown County (Mixed-humid) · Butler County (Mixed-humid) · Clermont County (Mixed-humid) · Clinton County (Mixed-humid) · Fayette County (Mixed-humid) · Franklin County (Mixed-humid) · Gallia County (Mixed-humid) · Greene County (Mixed-humid) · Hamilton County (Mixed-humid) · Highland County (Mixed-humid) · Hocking County (Mixed-humid) · Jackson County (Mixed-humid) · Lawrence County (Mixed-humid) · Madison County (Mixed-humid) · Meigs County (Mixed-humid) · Pickaway County (Mixed-humid) · Pike County (Mixed-humid) · Ross County (Mixed-humid) · Scioto County (Mixed-humid) · Vinton County (Mixed-humid) · Warren County (Mixed-humid) · Washington County (Mixed-humid)
Zone 5A: cool-humid
Attic target R60 (ENERGY STAR)Allen County (Cold) · Ashland County (Cold) · Ashtabula County (Cold) · Auglaize County (Cold) · Belmont County (Cold) · Carroll County (Cold) · Champaign County (Cold) · Clark County (Cold) · Columbiana County (Cold) · Coshocton County (Cold) · Crawford County (Cold) · Cuyahoga County (Cold) · Darke County (Cold) · Defiance County (Cold) · Delaware County (Cold) · Erie County (Cold) · Fairfield County (Cold) · Fulton County (Cold) · Geauga County (Cold) · Guernsey County (Cold) · Hancock County (Cold) · Hardin County (Cold) · Harrison County (Cold) · Henry County (Cold) · Holmes County (Cold) · Huron County (Cold) · Jefferson County (Cold) · Knox County (Cold) · Lake County (Cold) · Licking County (Cold) · Logan County (Cold) · Lorain County (Cold) · Lucas County (Cold) · Mahoning County (Cold) · Marion County (Cold) · Medina County (Cold) · Mercer County (Cold) · Miami County (Cold) · Monroe County (Cold) · Montgomery County (Cold) · Morgan County (Cold) · Morrow County (Cold) · Muskingum County (Cold) · Noble County (Cold) · Ottawa County (Cold) · Paulding County (Cold) · Perry County (Cold) · Portage County (Cold) · Preble County (Cold) · Putnam County (Cold) · Richland County (Cold) · Sandusky County (Cold) · Seneca County (Cold) · Shelby County (Cold) · Stark County (Cold) · Summit County (Cold) · Trumbull County (Cold) · Tuscarawas County (Cold) · Union County (Cold) · Van Wert County (Cold) · Wayne County (Cold) · Williams County (Cold) · Wood County (Cold) · Wyandot County (Cold)