How it Works
R-Value = Thickness (inches) × R-per-inch of material. Total R = Sum of all layers (studs, insulation, sheathing).
What is R-Value Insulation Calculator?
Sums the R-values of various building materials to determine the total insulating power of a wall or ceiling assembly.
Step-by-Step Guide
1. Select Material
Fiberglass, Foam, Cellulose, etc.
2. Input Thickness
Depth in inches.
3. Add Layers
Sum multiple materials.
4. Result
Total Assembly R-Value.
Example
Input: 3.5in Fiberglass (R-13) + 1in Foam (R-5)
Result: R-18 Total
FAQ
What is R-value?
Measure of resistance to heat flow.
Fiberglass vs Foam?
Spray foam has higher R/inch but costs more.
Do I add studs?
Yes, wood has an R-value (~1.2/inch), but it acts as a thermal bridge.
Settling?
Blown-in insulation settles over time, reducing R-value.
Vapor barrier?
Essential to prevent mold; doesn't add R-value.
👷 Safety First: Always adhere to local building codes and regulations. Wear appropriate Personal Protective Equipment (PPE) when performing construction tasks.
Conclusion
Higher R-values mean better energy efficiency. Meeting local energy codes often requires specific R-values for walls (e.g., R-20) and attics (e.g., R-49). Don't ignore thermal bridging through studs, which lowers effective R-value.