Radiant barriers make home more comfortable, energy efficient

Published 12:01 am Sunday, July 10, 2011

‘Radiant barrier” is a relatively new term in the world of home improvement. So what exactly is it, how and why does it work, and what makes radiant barrier foil effective in reducing energy bills?

The answer is simple: A radiant barrier blocks heat from entering or escaping an area. If you use a sunshield for your windshield then you have first-hand experience with a radiant barrier.

Radiant barrier material is much like the foil wrap we use in our kitchen, except professional grade radiant foil is much stronger and tear-proof. Aluminum is used because it reflects radiant heat the same way tin foil keeps your turkey from burning on Thanksgiving.

With a house — in the summertime — the foil acts like a shade over the home, reducing heat gain. In the winter, the foil works to keep the heat inside, reducing heat loss and making the interior more comfortable and energy efficient.

By installing a radiant barrier, the radiant heat that would normally be absorbed by your attic insulation is now reflected away, back out through your roof.

Although you cannot see radiant heat, you feel it, even without touching the heat source. For example, if you have a hot skillet on the stove and you put your hand above the skillet, you will feel the heat from the skillet without actually touching it: That is radiant heat.

Radiant heat travels at the speed of light until the heat is either absorbed or reflected. A dark roof absorbs almost all the sun’s radiant energy and can easily reach 170 degrees on a hot, sunny day. The heat is then re-radiated in all directions (including your attic).

Once the heat has radiated into your attic, the heat begins to warm the insulation at your ceiling. Eventually the insulation becomes overheated and your home begins to heat up, too. With a radiant barrier, most of the heat is reflected and your attic insulation remains cool, and, thus your home does as well.

Radiant barrier foil insulation reflects about 97 percent of the radiant energy that hits it.

Beware of the claims some companies make promising 30 percent to 50 percent savings by installing radiant barrier foil attic insulation. Our investigation shows that savings are more likely to be in the 10-percent to 25-percent range, with some cases saving up to 30 percent.

We feel that a foil insulation barrier makes good sense and should be a part of your overall strategy to make your home more comfortable and energy efficient.

Here are a few more simple tips to add to your plan of increasing your homes overall energy efficiency:

•Air seal the home.

Seal and insulate the ductwork.

Install a radiant barrier.

Have the A/C system checked and cleaned.

Clean or change furnace filters monthly.

Increase attic ventilation.

Add more attic insulation.

Where we once recommended radiant foil contractors, we have found that there are companies such as www.atticfoil.com that offer materials on the internet for DIY installation. The task is far from rocket science and can save you big bucks.

For tips from James and Morris Carey, go to www.onthehouse.com or call the listener hot line, 800-737-2474, ext. 59. The Careys are also on KRKO (1380 AM) from 6 to 10 a.m. every Saturday.