Recommended Home Insulation R–Values
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.
Recommended insulation levels for retrofitting existing wood-framed buildings

Zone
|
Add Insulation to Attic
|
Floor
|
|
---|---|---|---|
Uninsulated Attic
|
Existing 3–4 Inches of Insulation
|
||
1 | R30 to R49 | R25 to R30 | R13 |
2 | R30 to R60 | R25 to R38 | R13 to R19 |
3 | R30 to R60 | R25 to R38 | R19 to R25 |
4 | R38 to R60 | R38 | R25 to R30 |
5 to 8 | R49 to R60 | R38 to R49 | R25 to R30 |
Wall Insulation - Whenever exterior siding is removed on an: Uninsulated wood-frame wall:
OR Insulated wood-frame wall:
|