Recommended insulation levels for retrofitting existing wood-framed buildings

Insulation level are specified by R-Value. R-Value is a measure of insulation’s ability to resist heat traveling through it. The higher the R-Value the better the thermal performance of the insulation. The table below shows what levels of insulation are cost-effective for different climates and locations in the home.

Zone	Add Insulation to Attic		Floor
	Uninsulated Attic	Existing 3–4 Inches of Insulation

1	R30 - R49	R25 - R30	R13
2	R30 - R60	R25 - R38	R13 to R19
3	R30 - R60	R25 - R38	R19 to R25
4	R38 - R60	R38	R25 to R30
5-7	R49 - R60	R28 - R49	R25 to R30