How Much Is Enough?

The amount of insulation recommended for your home is dependent on where you live, but here are some general guidelines:

• Attic Insulation: Houses in a cold climate should have a minimum of R-49 in the attic, which is equivalent to approximately 16″ of fiberglass insulation. Warmer climates only require an R-38 or higher, or about 12″ or more.

• Wall Insulation: While wall insulation is limited by the width of the studs, different materials provide higher or lower R-values. Fiberglass batts for standard 2×4 walls are now available in low, medium, and high density products that range from R-11 to R-15. Sprayed foam insulation in the same wall cavity can range from an R-14 to an R-28 depending on the product that is used.

• Floor Insulation: While there are additional considerations—such as venting and moisture problems—to take into account when you insulate under floors, the United States Department of Energy recommends an R-25 rating in cold climates and an R-11 in warmer parts of the country.