Ohio is located in both the Northern and North-Central climate zones. Depending specifically on where your house is located, you will want to choose windows that are ENERGY STAR qualified for the climate zone in which you live.
A portion of Ohio is located in the Northern Climate Zone (see page 5), where an efficient window will significantly reduce heating energy use in the winter. Windows qualifying in the Northern climate zone may follow either prescriptive or equivalent energy performance criteria. Under the prescriptive criteria, windows must have a U-factor of 0.30 or less and any SHGC. With equivalent energy performance, windows qualify with a U-factor of 0.31 if the SHGC is 0.35 or more OR with a U-factor of 0.32 if the SHGC is 0.40 or more.
Another portion of Ohio is located in the North-Central Climate Zone (see page 5), where an efficient window will significantly reduce heating energy use in the winter, as well as mitigate cooling energy needs in the summer. All ENERGY STAR qualifying windows for the North-Central climate zone must have a U-factor rating of 0.32 or below and a SHGC rating of 0.40 or below.