How Much Is Enough Attic Insulation

How well a particular insulation works is expressed by the r value which ranges from 2 0 to 8 0 per inch of insulation.

How much is enough attic insulation.

These recommendations are for true r values not the nominal values listed on insulation packaging. Energy information administration predicts that this. The higher the r value the better job the insulation does at preventing the transfer of heat. Blown in insulation is the least expensive option and ideal for older attics.

First off you should know that insulating your attic isn t cheap. R value is a measure of insulation s ability to resist heat flow. If it is less than r 30 which is to say 11 inches of fiber glass rock wool or 8 inches of cellulose then you may want to add more. 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.

Estimates suggest that it ll cost around 1 340. The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type. To find out if you have enough insulation in your attic measure the thickness of the insulation from top to bottom using a ruler. Use our roll insulation calculator to estimate the amount of wall insulation crawlspace insulation or attic insulation you need for your project.

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. Add the right kind of insulation. Spray foam while the most expensive is best for noise reduction and new construction. For example if you install r 19 fiberglass batts in 2x6 frame walls with the studs 16 inches on center double top plates and other elements of standard framing the actual r value of the whole wall with the r 19 insulation will be about r 15.

If your attic insulation covers your joists and is distributed evenly you probably have enough. The higher the r value the better the thermal performance of the insulation. Check the chart below as a down and dirty guide of your existing r value. 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.