Blown Attic Insulation R Value Per Inch

Input depth of existing blown in insulation in inches.

Blown attic insulation r value per inch.

For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3. The r value per inch for different types of insulation varies depending on the. Cellulose insulation has a baseline r value of 3 8 per inch. As a benchmark one inch of solid wood has an r value of 1.

Some installations can yield a higher r value than traditional batt insulation for the same thickness and can fill even the smallest cavities creating an effective air barrier. By today s standards most homes built more than 10 years ago can be considered under insulated. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. The r value of insulation is a measure of how well it reduces the flow of heat and cold into and out of your house.

While there are additional considerations such as venting and moisture problems to take into account when you insulate under floors the united states department of energy recommends an r 25 rating in cold climates and an r 11 in warmer parts of the country. Click the button to calculate the approximate r value for this job. 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. The higher the r value per inch of thickness the better job the insulation will do when you heat or cool your home.

Foam in place insulation can be blown into walls on attic surfaces or under floors to insulate and reduce air leakage. You can use the small pressurized cans of foam.