Radiant Barriers: Myths, Facts, and Benefits
What is a radiant barrier?
A radiant barrier is a reflective surface that prevents radiant heat from entering a home’s heat envelope. When infrared radiation from the sun hits a home’s roof, it heats up the roofing material, which then radiates that heat back out in all directions. A radiant barrier will reflect this heat back toward the roof, keeping your house cooler in the summer.
Radiant barriers have the most impact in reducing radiant heat gain during the summer. The U.S. Department of Energy says that radiant barriers can reduce cooling costs by 5-10 percent in a warm, sunny climate.
Radiant barrier sheathing, which is plywood or OSB board with foil adhered to one side, is often used in new homes, with the foil facing into the attic space. Older homes can be retrofitted for extra energy savings by attaching radiant barrier material to the attic ceiling or floor.
Is a radiant barrier worth it?
The value of a radiant barrier in your home depends on your climate, sun exposure, and current insulation. Here are some situations where a radiant barrier might benefit you most:
Your attic is poorly insulated.
The more insulated your attic, the less difference a radiant barrier will make. Insulation prevents conductive heat from entering your home by absorbing it, and that means there will be less heat for the radiant barrier to mitigate. If you have an older home with poorer insulation, a radiant barrier may be a cheaper option than replacing insulation.
Your roof gets direct sunlight.
The primary job of a radiant barrier is to reduce heat gain from a hot roof, and a roof that gets more sun exposure will get hotter. If you live in the northern hemisphere and your roof is south-facing, a radiant barrier will be more effective on that side.
You may also want to consider installing a radiant barrier in barns or outbuildings that are poorly or not at all insulated. Buildings with metal roofs could benefit greatly from radiant barriers, since metal can get very hot under the sun.
There is ductwork in your attic.
Keeping your attic cool is extra important if you have air-conditioning ducts running through it. Unfortunately, a lot of older homes have ductwork in unconditioned attics. Again, in this case, installing a radiant barrier is usually a simpler and less expensive project than installing insulation in your attic.
Installing a radiant barrier
There are a few things to keep in mind if you want to preserve the effectiveness of a radiant barrier. First, radiant barriers need an air space in front of them. If they’re sandwiched between two pieces of insulation or siding, they become conductors and will actively be working against your insulation.
Second, a radiant barrier is only effective if it is reflective. Accumulation of dust on the foil surface will lower reflectiveness, and this is one reason that the installation of a radiant barrier on the attic floor, rather than the ceiling, could be problematic.
Third, you should know the difference between perforated and non-perforated radiant barriers. A radiant barrier that is non-perforated will not allow water vapor to pass through. If a non-perforated barrier is installed in your attic, the warm air and moisture from inside the house will rise and have nowhere to go. It will condense on the radiant barrier and make the attic wet, damaging your home. A perforated barrier has tiny holes that allow air and water vapor to pass through.
Radiant barrier scams and exaggerations
There is a lot of misinformation about radiant barriers out there. Beware of scams, such as “paint-on” radiant barriers, or too-good-to-be-true statistics about the energy savings they can bring, especially in cooler climates. Minnesota officials, for example, have advised against radiant barriers for state residents. This was in response to aggressive radiant barrier marketing efforts in that state. Consult with your state, local, or regional planning department about whether a radiant barrier is a good investment in your climate.
Trust the protection experts
If you live in a hot climate, and have a home that was not built with radiant barrier sheathing, installing a radiant barrier in your attic will likely lead to noticeable energy savings. It can also be a DIY project. Americover’s Super R Diamond radiant barriers are perfect for home retrofits. Avoid the scams and misinformation! Call us at 760.528.5263 for expert advice!