Understanding Insulation ROI
Heat loss through a surface is inversely proportional to its R-value: Q = A * delta-T / R. Upgrading from R-11 to R-38 reduces heat flow by 71%. The savings depend on heating/cooling degree days (HDD/CDD) which measure climate severity. Attic insulation typically offers the best ROI, often paying back in 2-5 years. The DOE recommends R-38 to R-60 for attics in most U.S. climate zones.