The sun directs radiant heat to the sides and roofs of houses. Normally, this radiant heat is transferred from the roof to the ceiling to the inside of the house. Radiant barriers can be applied directly to the surfaces that receive the sun's radiation, such as the roof or attic of a house. This technology blocks the flow of radiant heat by reflecting it instead of absorbing it. In cooperation with the normal insulation in a house, radiant barriers can block out a good portion of heat, allowing a homeowner to lower his or her air conditioner usage.