The higher the R value, the better the thermal performance of the insulation. The recommended level for most attics is to insulate them to R-38 or approximately 10 to 14 inches, depending on the type of insulation. ENERGYSTAR recommends an R value of R-38 for most homes. This translates to approximately 12 inches.
of insulation. Don't worry if the fiberglass insulation in the center of the house seems too thin. It will expand to a thickness of 6 inches. If you already have six inches of insulation and want to get to the recommended R-38, add an “attic blanket.” Now that you have an idea of the depth you need, you need to measure the width and length of your attic.
In some ways, it's easier to work with rigid foam insulation, but fiberglass is usually easier to climb into the attic. If you don't have enough, use a measuring tape to measure the depth of insulation in your attic. It's possible that houses built before the energy crisis of the early 1970s only had a little fiberglass insulation in the attic or empty cavities between the beams. Whatever you decide, insulation remains one of the best ways to improve the energy efficiency of your home.
