Insulation R-Value Calculator
Calculate the total thermal resistance (R-Value) of your wall or attic based on insulation thickness and material.
What is R-Value?
In construction, the R-Value measures a material's resistance to conductive heat flow. The higher the R-Value, the greater the insulating effectiveness. Building codes mandate specific R-Values for walls and attics depending on your climate zone.
Comparing Materials
Different materials provide drastically different R-Values per inch of thickness:
- Fiberglass Batt: ~R-3.14 per inch. Affordable and standard.
- Closed-Cell Spray Foam: ~R-6.0 per inch. Highly effective and creates a vapor barrier, but expensive.
- Mineral Wool: ~R-4.0 per inch. Excellent fire resistance and soundproofing.
Frequently Asked Questions
Do multiple layers stack?
Yes. If you place an R-13 fiberglass batt over another R-13 batt, your total system insulation is R-26.
Disclaimer: This calculator is for educational and learning purposes only. While we strive for accuracy, calculations are provided "as-is" without warranty. The accuracy of results depends on the accuracy of input data provided. Always verify important calculations independently. For critical applications or when accuracy is essential, consult with appropriate professionals or use verified reference sources. Educational calculators may contain rounding or approximations.