Heat barriers savings will make you radiant
Have you received a postcard in the mail lately with marketing lines such as:
1. Did you enjoy paying your utility bills this month?
2. Did you know you may be paying up to 40 percent too much every month?
3. See what the Utility Companies may not want you to know!
4. Free Steak Dinner!
5. This technology was developed by NASA and is now being introduced to the general public!
Lately, a few companies have been using lines like these to convince you to install a radiant barrier or radiation control coating. But will these actions provide significant energy savings in your home?
On a sunny summer day, solar energy is absorbed by the roof, heating roof sheathing and causing the underside of the sheathing and roof framing to become hot. These surfaces then radiate heat downward toward the home. Radiant barriers reduce that energy flow and heat radiation, and by reducing heat energy reaching the attic floor, radiant barriers also reduce the attic’s ambient air temperature.
In the winter, radiant barriers can reduce indoor heat losses through the ceiling, especially during winter nights when the roof surface is coldest. However, radiant barriers also reduce beneficial daytime heat gains due to solar heating of the roof. Depending on your climate, level of attic insulation and other factors, the net winter effect can be positive or negative.
So what kind of savings can you expect in Nebraska?
Oak Ridge National Laboratory (ORNL) is a multi-program science and technology national laboratory managed for the U.S. Department of Energy. ORNL’s calculations in Nebraska’s weather zone show savings varies from $0 to $0.03 per square foot. For the typical 1,540 square foot attic in a Nebraska home, the first year’s savings would vary from $0 to $61.60. Considering installation could cost more than $2,000, it may be more than 30 years for your energy savings to pay for the improvement.
Even so, if you determine a radiant barrier is appropriate for your attic, make sure the product you install has an appropriate permeability rating to allow any moisture to “travel” through the barrier into the attic where it can be vented out of the home. In Nebraska, barriers are often laid atop the home’s existing attic insulation with the reflective side up. Although this is the simplest installation method, there are several disadvantages:
• Dust will settle on the reflective side of the barrier, decreasing its effectiveness.
• Traffic (if the attic is used for storage) will damage it.
• Moisture can be trapped where it will soak the insulation and potentially lead to mold problems.
• Kitchen and bathroom vents and recessed lights should not be covered with the radiant barrier.
“There are many technologies available today that reduce energy usage in your home or business,” said CGO Energy Efficiency Supervisor Steve Zach. “We strongly recommend doing your homework before undertaking a project, especially one that involves a significant monetary investment. As always, NPPD’s Energy Efficiency team is here to support and help you with the decision making process.”