To maintain comfort in your home, the heat lost in winter must be replaced by your heating system and the heat gained in summer must be removed by your air conditioner. Insulating ceilings, walls, and floors decreases this heat flow by providing an effective resistance to the flow of heat.

Heat flows naturally from a warmer to a cooler space. In winter, heat flow moves directly from heated living spaces to adjacent unheated attics, garages, and basements, or to the outdoors; or indirectly through interior ceilings, walls, and floors – wherever there is a difference in temperature. During the cooling season, heat flows from outdoors to the house interior.