Roof Insulation is important for year-round comfort. Insulation stops all heat from moving through it, whether the heat is on the inside of your home or the outside of your home. This means that in the winter, insulation will stop heat from escaping and in the summer, insulation will stop heat from entering into your home. The actual resistance to heat flow through the roof insulation will be at least 80% of the design thermal resistance, provided that the roofing membrane is free of leaks. The roof insulation will remain in a reroofable condition should the roof membrane require replacement (excluding damage caused by fastener pullout during removal of the old membrane.)