R-value measures the insulation’s resistance to heat traveling through it according to ENERGY STAR. a higher R-value means the insulation has more resistance to heat transfer. In other words, the thicker your insulation is, the more you can efficiently keep your home interior comfortable.
If you double the R-value of your insulation, the heat transferring into or out of your home decreases to one-half. Doubling the insulation R-value will assist in keeping your home’s inside spaces comfortable, but probably will not double your entire home’s resistance to heat loss. This is due to the possible compression of the insulation and other factors such as doors and windows.
Other factors that determine the best R-value to use are the area of your home where the insulation is installed, the climate in your region and the type of HVAC system you use.