Menu
When trying to determine your current R-Value in the attic, use a ruler to measure the depth of the insulation and multiply the depth by the R-Value of the material.
For example, and attic with 6 inches of Modern insulation would have an estimated R-Value of 22.5 (6 inches x 3.75 R-Value per inch)
Unless you still have the packaging for the insulation used in the attic, it will be hard to measure the exact R-Value of the installed product. To calculate the R-Value use the following guidelines for estimation purposes only:
Material |
R-Value / Inch |
|---|---|
| Blown-in Cellulose | 3.75 |
| Blown-in Fiberglass | 3.7 |
| Fiberglass Batts | 3.7 |
| Cotton Batts | 3.7 |
| Open-cell Foam | 3.6 |
| Close-cell Foam | 5.8 |
Remember, cellulose insulation can be blown on top of existing insulation to improve R-Values without removing the already installed insulation.
