Yes, of course, it does matter. As the air inside the sleeping pad attempts to reach temperature equilibrium with the ground, its R-value measures the effectiveness of the sleeping pad at resisting heat. The R-value of a place is more significant when it has a higher value. R-Values for sleeping pads usually range from 2 to 5, with five being the best. The ideal sleeping pad should have an R-Value of 4 or more.