Radiant Barriers Result in Energy Savings and Lower Cooling Costs

Think of radiant barriers as shade for your house. Also called reflective insulation, reflective foil, or reflective foil laminates (RFL), radiant barriers typically consist of a reflective material like aluminum attached to one or both sides of another, different layer. That secondary material may be plastic film, kraft paper, cardboard, oriented strand board, or something else. Some radiant barriers are reinforced with fiber for added durability.

These reflective insulation products are mostly used in attics but also work well in cavity walls, and around door openings, water heaters, and pipes.

How Reflective Insulation Can Cut Energy Costs

When the sun shines, heat makes it way through your roof into your attic and then to the cooler attic elements, like the air ducts and floor. Through reflection, rather than absorption, a radiant barrier decreases the radiant heat transfer from the roof's underside to the other attic surfaces and, subsequently, into your home.

Most foil-type radiant barriers have a low emissivity of 0.05 or less, which means they block about 95 to 97 percent of radiant heat. Emissivity is a measure of the ability of a surface to radiate energy. During the hottest summer days, you can expect temperature drops of about 10-plus degrees. This equals energy savings and lower coolings costs--about 5 to 10 percent worth.

Radiant barriers are more effective in hot, rather than cold, climates, especially in attics with cooling air ducts. In chilly regions, it is better to install greater levels of common insulation--fiberglass, sprayed foam, mineral wool, cellulose--instead, for reduced energy costs. Reflective insulation, however, can be used in tandem with other types of insulation.

Costs and Installation

Radiant barriers with the Energy Star label have been proven to be energy efficient. Those that are installed in 2010 as insulation for a primary residence qualify for federal tax credits under the 2009 American Recovery and Reinvestment Act (ARRA). Radiation barriers cost between about 10 and 70 cents per square foot plus installation. Some that combine reflectivity and insulation are pricier.

Reflective insulation is easy to install, as it is clean, lightweight, and maneuverable. If you do it yourself, follow the manufacturer's safety precautions and instructions. If you contract it out, hire a certified installer.