Green Energy Radiant Barriers

Definition

• A radiant barrier reflects back heat absorbed by the home's shell. In the warm months, the temperature in the attic rises high above 100 degrees Fahrenheit. Adding a radiant barrier on the attic floor, also called reflective insulation, means that the barrier will send some heat back to the roof. The home's cooling system has less hot air to cool if the radiant barrier works.

Similarity to Insulation

• Installing a radiant barrier to your home gives you an option in addition to upgrading the home's conventional insulation. You want to reduce the load on the home's air conditioning system by changing the direction of the heat flow. With a radiant barrier installed on the floor of the attic, you don't just send hot air back up, but you reduce the amount of hot air penetrating rooms below the attic.

Composition

• Look for a reflective insulation product that meets your requirements for green material. According to the Virginia Cooperative Extension's Robert Grisso and Martha A. Walker, Ph.D., this insulation consists of aluminum foil with a backing made of Kraft paper, roof sheathing, plastic film, cardboard or another material. They also note that reflective insulation performs if there is available airspace next to the insulation product's reflective side.

Considerations

• Homeowners can place a radiant heat barrier in other places besides the attic floor. Install the barrier between wall studs or roof rafters. Also ensure that the insulation barrier permits water vapor to pass through it. Some products will also reflect heat on both sides, giving you a choice of which side to point towards an open airspace. Buy a material with high reflectivity and low emittance, or generating little heat. Your purchase of this green energy option does not eliminate a need for attic insulation. If you have strong insulation (i.e. R-30 or higher), your savings on cooling costs will be lower than if your home has low insulation (R-11 or less), according to Grisso and Walker.