Insulation R-Value Calculator
Insulation depth needed by climate zone and material.
Add
24.0 in
to reach R-60
Target R-value: R-60
Existing: R-0
R needed: R-60
Inches at R-2.5/in: 24.0 inches
Targets follow the IECC 2021 prescriptive R-values for residential. Existing fiberglass batt R-13 is typical for 2x4 walls; R-19 to R-30 in the attic is common for older homes. Cellulose settles 10 to 20 percent over the first year.
About
Pick climate zone (1–8) and area (attic, wall, floor, crawl). The tool shows the IECC 2021 target R-value, subtracts your existing R, and converts to inches of the material you're adding.
How to use
- Pick your climate zone.
- Pick the area to insulate.
- Pick the material.
FAQ
Where do I find my climate zone?+
The DOE map by county. Zone 1 is south Florida and Hawaii. Zone 4 covers most of the mid-Atlantic. Zone 8 is interior Alaska.