Insulation R-Value Calculator

Calculate the total thermal resistance (R-Value) of your wall or attic based on insulation thickness and material.

Total R-ValueR-12.6

Embed Calculator

Copy this HTML code to embed the calculator on your website:

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.