Batt Insulation R-Value Calculator
Total R-value from stacked insulation layers.
Enter your values
ⓘ Live results
Results
- Total R-value
- R-19
- Target R-value
- R-38
- Shortfall/surplus
- -19
Quick answer
Total R-value is simply the sum of each insulation layer's R-value when layers are stacked without compression.
R total = R1 + R2 + ... (uncompressed)
How to use the Batt Insulation R-Value Calculator
- 1Enter the R-value printed on each batt or roll layer.
- 2Only stack layers that are not compressed, since compression lowers effective R-value.
- 3Compare the total to your climate zone's recommended R-value.
Worked example
Using the values the calculator loads with:
Inputs
- Layer 1 R-value19
- Layer 2 R-value0
- Layer 3 R-value0
- Target R-value38
Results
- Total R-valueR-19
- Target R-valueR-38
- Shortfall/surplus-19
Frequently asked questions
Does compressing a batt increase R-value?
No, compressing insulation reduces its R-value because trapped air is the insulator.
Should I run insulation perpendicular?
A second layer run perpendicular to the first helps cover framing gaps (thermal bridging).
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.