Insulating your attic increases the energy efficiency of your home, is relatively inexpensive and lasts for decades. When you’re choosing attic insulation, these steps will help you reach the 16 inches that the U.S. Department of Energy recommends for our climate. Sixteen inches of insulation translates to an R-value around 38, which gives you 38 hours of protection against heat gain or loss. The “R” stands for resistance and each value that the insulation carries indicates how many hours it resists temperature change.