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Determining Current Home Attic Insulation R-Value

When trying to determine your current R-Value in the attic, use a ruler to measure the depth of the insulation and multiply the depth by the R-Value of the material.

For example, and attic with 6 inches of Modern insulation would have an estimated R-Value of 22.5 (6 inches x 3.75 R-Value per inch)

Unless you still have the packaging for the insulation used in the attic, it will be hard to measure the exact R-Value of the installed product. To calculate the R-Value use the following guidelines for estimation purposes only:

Material
R-Value / Inch
Blown-in Cellulose 3.75
Blown-in Fiberglass 3.7
Fiberglass Batts 3.7
Cotton Batts 3.7
Open-cell Foam 3.6
Close-cell Foam 5.8

Remember, cellulose insulation can be blown on top of existing insulation to improve R-Values without removing the already installed insulation.

Contact a CIMA Producer in your state for referrals on energy auditors and professional insulation contractors.


 
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