How Much Attic Insulation Should I Have

Existing 3 4 inches of insulation.

How much attic insulation should i have.

Where do you live. There are two factors to consider when planning to insulate your attic. The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type. The short answer is as much as you can get and a good rule of thumb is to have a r value of 38 in your attic.

To prevent heat loss the attic space should be well insulated. Twelve inches is often plenty when one or more of these situations is true you re going to need more insulation. It can cost anywhere from 1 700 to 2 100 or between 1 50 and 3 50 per foot to insulate an attic depending on what insulation material you choose. Spray foam while the most expensive is best for noise reduction and new construction.

But how much insulation is enough for the attic. Get fair costs for your specific project requirements. Fiberglass and cellulose insulation have r values of 2 9 to 3 8 per inch while sprayed foam insulation can go as high as 8 0 per inch. See professionally prepared estimates for attic insulation work.

Department of energy it s recommended that attics have an r 38 to r 49 or about 12 to 15 of fiberglass or cellulose insulation. See typical tasks and time to insulate an attic along with per unit costs and material requirements. Add the right kind of insulation when adding additional insulation you do not have to use the same type of insulation that currently exists in your attic. Learn more about insulation r values.

For homes in the boise idaho area the insulation r value climate zone is 5. If you look at the chart above you can see that the attic should achieve an r value between r38 and r60 depending on the current insulation levels. The cost to insulate an attic starts at 1 68 3 25 per square foot but can vary significantly with site conditions and options. When you can see the joists you definitely need more insulation.

Each bag lists the required depths for a range of r values and the number of bags needed to cover 1 000 square feet at those depths. Blown in insulation is the least expensive option and ideal for older attics. For batts or rolls calculate the number based on the width and length of the product you re using. Measure your attic s square footage.

However the real answer is a bit more complex. Most homes will keep fairly cool with just six to eight inches of insulation but over time insulation settles so having a little extra doesn t hurt. According to the u s. For loose fill read labels.

If your insulation doesn t measure up and you need more installation can be done as a weekend diy project or you can call a professional installer to handle the job.