How Much Attic Insulation Should I Have

Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation.

How much attic insulation should i have.

Wy mt nh me wi etc. Click the button to calculate the depth in inches and pounds of total insulation required for this job. This calculator is to be used as an estimating tool only. Your attic should have a certain amount of insulation in it and the recommended level of insulation for your attic is dependent on where you live.

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. 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. Most of ga al ar sc ok etc to a high of 49 for zones 6 8 i e. The main factors that impact the cost are.

Insulation level are specified by r value. Type and material of your insulation. The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type. When combined with whatever insulation might already be in the joist cavities a 12 inch additional blanket will very likely meet the energystar recommendations for even very cold climates.

According to the u s. Input length width and desired r value of the area to be insulated. 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. R value is a measure of insulation s ability to resist heat traveling through it.

The higher the r value the better the thermal performance of the insulation. Spray foam while the most expensive is best for noise reduction and new construction. The table below shows what levels of insulation are cost effective for different climates and locations in the home. 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.

Blown in insulation is the least expensive option and ideal for older attics. That said air resistance and interference such as vent grates reduces the area of true ventilation. This range varies from a low of 30 for homes with heat pumps or natural gas furnaces in zone 3 i e. Square footage of your attic.

The zone you live in will determine how much insulation you need in your attic. According to home advisor insulating your attic can cost between 1700 to 2100. In an attic a 12 inch fiberglass blanket can provide an extra r value of 34 8 to 45 6.