Attic Insulation R Values Inches

The r value is r 3 5 to r 3 6 per inch so filling a 2 4 cavity yields about an r 13.

Attic insulation r values inches.

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. Batts light weight yellow pink or white. Vermiculite or perlite 2 7 x depth.

Depth inches total insulation r value. Small gray flat pieces or fibers from newsprint cellulose 3 7 x depth. Rock wool 2 8 x depth. As you can see there s some variation in r value depending on the particular type and brand of products used.

Click the button to calculate the approximate r value for this job. Input depth of existing blown in insulation in inches. As a benchmark one inch of solid wood has an r value of 1. 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. Dense gray or near white may have black specs. Achieving greater r values in exterior walls.

You can achieve better thermal performance in your attic by adding an additional layer of insulation. 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. R value of insulation by type.