Attic Insulation R Values Inches

Vermiculite or perlite 2 7 x depth.

Attic insulation r values inches.

In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and an inch of blown cellulose in an attic has an r value of 3 2 3 7. Closed cell spray foam insulation. Closed cell spray foam has a far better r value per inch than other less effective insulations like cellulose fiberglass or even open cell foam. This calculator is to be used as an estimating tool only.

Here are the r values per inch of the most common types of insulation. Light weight yellow pink or white. Input depth of existing blown in insulation in inches. The higher the r value the better the thermal performance of the insulation.

Rock wool 2 8 x depth. R value of insulation by type. As a benchmark one inch of solid wood has an r value of 1. Batts light weight yellow pink or white.

The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13. You can achieve better thermal performance in your attic by adding an additional layer of insulation. Achieving greater r values in exterior walls. Fiberglass 2 5 x depth.

Depth inches total insulation r value. R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another. It has a lower r value per inch than closed cell foam and is vapor permeable. As you can see there s some variation in r value depending on the particular type and brand of products used.