How radiant barriers work
I’ve heard that installing a radiant barrier in my attic could save me a lot of money on my energy bill. Can it?—Don
A radiant barrier reflects radiant heat and can be used to keep heat in a home during the winter and to keep heat out in the summer.
Radiant barriers often look like aluminum foil. Sometimes the foil is fastened to oriented strand board or foam board, but the foil will only reflect radiant heat toward an air space of at least 1 inch. If the foil is in contact with a solid material, it conducts excess heat into that material.
A common location to use radiant barriers is the attic; radiant energy from the sun is sent back out of the roof before it can heat the air and insulation in your home. Commonly sold as a roll of shiny, aluminum material, it is usually mounted on the underside of the framing that supports the roof.
The radiant barrier is only effective in reflecting radiant heat, not as insulation or as a wrap to block air loss. While solutions such as an attic fan try to remove the heat once it has accumulated, the radiant barrier stops the heat from building up in the first place.
Savings vary
So, is a radiant barrier a good investment? Sometimes. Do some research, as savings vary in each situation and there are many inaccurate claims made about the cost savings they bring.
The net impact of a radiant barrier depends on whether you live in a hot- or cold-weather climate. Homes in Florida retrofitted with attic radiant barrier systems reduced air conditioning energy use by about 9 percent. In colder climates, the radiant barrier that reflects unwanted heat outside of the house in the summer will also reflect heat away from the house in the winter. Therefore, the cooling bill may decrease but the heating bill may increase.
The best way to compare your energy efficiency opportunities is to schedule an energy audit of your home with your local electric cooperative.
PATRICK KEEGAN and BRAD THIESSEN write on energy efficiency for the National Rural Electric Cooperative Association.
