Radiant barrier insulation can help you save energy and money depending on where you live. Here’s a look at how it works and where it is most beneficial.
Heat from any source can be absorbed or reflected. Dark colors absorb heat, while light colors are more reflective.
You may have noticed that when you wear dark clothing in warm weather, you will feel hotter. This is because the absorption of light is greater on dark surfaces.
The common practice of using dark colors on rooftops causes cooling bills to rise in warm climates. Scientists have recommended painting flat rooftops white in large southern cities where energy use in the summer is often exorbitant.
A homeowner might be averse to painting shingles white. But, reflective metal roof shingles are available as an alternative. Depending on the material, they would probably work better than a coat of white paint anyway.
Aluminum is the material usually used for this purpose. In addition to shingles, aluminum chips can be added to loose-fill insulation in the attic. Reflective roof sheathing is available too. Even the floors of crawl spaces and attics can be coated with a reflective material to prevent heat from entering the home.
Radiant Heat Barrier
When air ducts are located in the attic, a radiant heat barrier can be attached to them. This reflects heat away from the ductwork and back into the attic, preventing the air from being warmed by the heat in the attic.
A common question asked by consumers is:
Will radiant barrier work under shingles without an airspace?
That question is answered in the video below:
Studies indicate that the use of properly installed barriers can reduce cooling costs by 5-10% in warm sunny climates. In some cases, the barriers allow for smaller air conditioning systems.
Tropical and southern temperate climates of the US are best suited for radiant barrier insulation. There is little or no benefit in areas where the summers are hot and the winters are cold. Reflecting heat from the sun during the winter months would raise heating bills as much as it would lower cooling bills in the summer.
Thermal insulation is a better choice for cold climates. It prevents heat from escaping.
In areas with hot summers and cold winters a combination of the minimum recommended amount of thermal insulation and the installation of a radiant heat barrier to protect attic cooling ducts could be a good choice. Modern ductwork is typically reflective anyway.
Another way to lower your cooling bills in the summer, without increasing your heating bills in the winter, is to plant deciduous trees at strategic points around your home. When they mature, the trees will shade the house in the summer. Since they lose their leaves in the winter, they will allow the maximum amount of sun to reach the house and help to warm it.