Have you seen them yet? The ads for this new wonder-product called “radiant barriers.” It looks a lot like tin foil. And, it actually is essentially silver-coated foil. The idea is this: You wrap the underside of your roof with this stuff and it bounces back radiant type heat created by heat sources (such as the sun, or your home heating system), thus creating a more efficiently heated and cooled home.
This technology has been shown to work pretty well in warm, Southern climates, when attached to the bottom side of the roof sheathing. The statistics for our geography, however, are not as persuasive. Installed in the Chicago area, in the location manufacturers suggest, the true results are very disappointing.
So, what is my beef with radiant barriers? My issue is this:
1) Homeowner often neglect insulation. By providing a sense that the radiant barrier alone is enough, homeowners often avoid investing in the tried-and-true value rewards of sufficient insulation.
2) Costly correction. When installed, as they often are, over the attic insulation it makes adding insulation later a difficult decision. If you lay insulation over the barrier, the small holes in the barrier can get clogged causing it to trap moisture. Very bad. If you pull up the barrier it will add to the cost of insulating the area and ruin the radiant barrier material.
3) It does not work. Even when installed properly, it just will not give you the savings for your Chicago area home. The Department of Energy states radiant barriers can save 5-10% in warm, sunny climates. Warm and sunny all year around, that is. Sound like Chicago to you?
So why are people buying it?
The firms I have heard of have very convincing marketing. They show a heat lamp with and without the barrier and what temperature it reflects. A heat lamp produces a different type of heat than your home furnace or boiler, more apt to be reflected by radiant barriers.
They guarantee savings. If you track your energy costs and don’t get a certain size savings they will give you money back. I’d be tempted to be convinced. But the amount they return is still quite a bit less than you have spent. I’d bet they still make money on the deal. Also, I think they bank on the fact that few people will take the time to track their savings and contact them is under performing.
If you want to save energy, go for the low-hanging fruit first. Get an energy audit from a
reputable firm (RESNET or BPI Certified). Install the suggested improvements. If you still want more savings and are not concerned with payback, consider alternative energy or get a radiant barrier installed on the bottom side of the roof sheathing, and know you will get a little savings during the summer months only.