What you should know about R-Values
The chart shows the R-values of Closed-Cell Spray Foam insulation. "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 insulation 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.
To get the specified R-value out of any insulation, it is essential that the insulation be installed properly
NOTE: Fact Sheet is a requirement of the Federal Trade Commission R-Value Rule, which governs all Insulation Products, which are marketed across state lines.