Wall R-Value Calculator

Calculate total thermal resistance (R-value) of a wall assembly by summing individual layer resistances.

Typical: 0.17 for 15 mph wind, 0.25 for 7.5 mph wind
h·ft²·°F/Btu
OSB/plywood: ~0.62 per inch, foam board varies by type
h·ft²·°F/Btu
Fiberglass batts: R-13 to R-21, spray foam varies
h·ft²·°F/Btu
1/2" drywall: ~0.45, wood paneling varies
h·ft²·°F/Btu
Still air: 0.68, moving air: 0.17
h·ft²·°F/Btu

Results

Total Wall R-Value-h·ft²·°F/Btu
U-Factor (1/R)-Btu/(h·ft²·°F)
References: ASHRAE Fundamentals Ch. 27 - Heat, Air, and Moisture Control in Building Assemblies