Pennsylvania climate zones
Pennsylvania’s 67 counties fall in 2 IECC 2021 climate zones: 4A (14), 5A (53).
Zone 4A: mixed-humid
Attic target R60 (ENERGY STAR)Adams County (Mixed-humid) · Berks County (Mixed-humid) · Bucks County (Mixed-humid) · Chester County (Mixed-humid) · Cumberland County (Mixed-humid) · Dauphin County (Mixed-humid) · Delaware County (Mixed-humid) · Franklin County (Mixed-humid) · Lancaster County (Mixed-humid) · Lebanon County (Mixed-humid) · Montgomery County (Mixed-humid) · Perry County (Mixed-humid) · Philadelphia County (Mixed-humid) · York County (Mixed-humid)
Zone 5A: cool-humid
Attic target R60 (ENERGY STAR)Allegheny County (Cold) · Armstrong County (Cold) · Beaver County (Cold) · Bedford County (Cold) · Blair County (Cold) · Bradford County (Cold) · Butler County (Cold) · Cambria County (Cold) · Cameron County (Cold) · Carbon County (Cold) · Centre County (Cold) · Clarion County (Cold) · Clearfield County (Cold) · Clinton County (Cold) · Columbia County (Cold) · Crawford County (Cold) · Elk County (Cold) · Erie County (Cold) · Fayette County (Cold) · Forest County (Cold) · Fulton County (Cold) · Greene County (Cold) · Huntingdon County (Cold) · Indiana County (Cold) · Jefferson County (Cold) · Juniata County (Cold) · Lackawanna County (Cold) · Lawrence County (Cold) · Lehigh County (Cold) · Luzerne County (Cold) · Lycoming County (Cold) · McKean County (Cold) · Mercer County (Cold) · Mifflin County (Cold) · Monroe County (Cold) · Montour County (Cold) · Northampton County (Cold) · Northumberland County (Cold) · Pike County (Cold) · Potter County (Cold) · Schuylkill County (Cold) · Snyder County (Cold) · Somerset County (Cold) · Sullivan County (Cold) · Susquehanna County (Cold) · Tioga County (Cold) · Union County (Cold) · Venango County (Cold) · Warren County (Cold) · Washington County (Cold) · Wayne County (Cold) · Westmoreland County (Cold) · Wyoming County (Cold)