Radiant barriers consist of a highly reflective material. This is the same reflective material as an astronauts’ space suit.
When a radiant barrier with a high reflectivity is installed on top of the attic much of the heat is reflected away from the home. Solar energy is absorbed by the shingles, heating the roof sheathing and causing the underside to become hot radiating heat into the attic. Radiant barriers reduce that that energy flow lowering the attic air temperature. When the roof is cold, in the winter, radiant barriers reduce indoor heat losses through the ceiling.
Radiant barriers are even more effective when your air conditioner is located in the attic Radiant barriers reduce energy losses from air conditioning ductwork in the attic in multiple ways. The cold air in the duct lines exchange energy in the attic; the energy loss is much less when the attic temperature lowered by the radiant barrier. By reducing the air temperature in the attic, your air handerler does not have to work as hard to condition the air. Installing a radiant barrier will produce a noticeable difference in the comfort throughout the house.