Energy-efficient homes are well insulated to reduce conductive heat loss through the envelope. To check the levels recommended for attics, walls, floors and windows, click the Insulation R-values button.

The purpose of insulation is holding heat in during the winter and keeping it out during the summer. Because of climate variations, homes in different regions of the country need different levels of insulation in the walls, ceilings, floors, and windows. To find out the recommended R-value in your area, contact your local utility or local building department.