What is an R-Value? | |
The higher the R-value, the greater the insulating power. Insulation materials have tiny pockets of trapped air. These pockets resist the transfer of heat through material. The ability of insulation to slow the transfer of heat is measured in R-values. An "R" is a measure of insulating power. The higher the R-value, the better the insulation material's ability to resist the flow of heat through it. What is insulation density? Density determines an insulation's R-value. R-values are not directly related to the thickness of the insulation product. For example, 3 1/2", R-15 Fiberglas(R) insulation for exterior 2 x 4 walls is the same thickness as its 3 1/2", R-11 counterpart; however, R-15 is a much denser product (more fibers per square inch) and, therefore, gives you greater insulating power, with an additional four R-values. Copyright 1996 Owens Corning Reprinted with permission, HouseNet, Inc. |