R means resistance to heat flow. The higher the R-value, the greater the insulating power. Compare insulation R-Values before you buy.

There are other factors to consider. The amount of insulation you need depends mainly on the climate you live in. Also, your fuel savings from insulation will depend upon the climate, the type and size of your house, the amount of insulating already in your house, and your fuel use patterns and family size. If you buy too much insulation, it will cost you more than what you'll save on fuel.

R-value testing is regulated by the Federal Trade Commission. The use of R-value tests allows the consumer to make choices based on the relative values for different products.