If you live in a house that was built in the last 50 years, chances are you’ve got some radiant barrier installed behind your walls, ceilings, or under the roof. The first patent for radiant barrier technology was actually filed in 1939 by Gordon Wilkes from the Massachusetts Institute of Technology. Radiant barrier is not the same thing as insulation, as it reflects heat, whereas insulation prevents heat transfer to the outside. Radiant barrier looks like the material as is used in space blankets, which have similar reflective properties to radiant barrier. The metallic (aluminum) nature of the foil causes it to reflect heat, which is the reason for its use as radiant barrier. If you’ve ever used a space blanket, you can imagine how effective radiant barrier can be. Interestingly, radiant heat isn’t the only kind of energy that can be reflected by foil. Similar types of materials are used to reflect radio frequencies, or RF. Both heat and RF energy have wavelengths found on the same electromagnetic spectrum, and therefore are reflective in similar ways to foil. Concerns in recent years over corporate espionage, WiFi hacking, TEMPEST, video and audio surveillance, and other forms of RF criminal exploitation have given rise to a whole host of new technologies to thwart these activities. Radiant barrier has been upgraded to RF foil, or rFoil, which provides the following benefits:
- Shields against radio frequencies ranging from 10GHz to 100GHz;
- Blocks up to 96% of radiant heat transfer, which keeps heat in during the winter and out during the summer;
- Reduces heating and cooling bills;
- The foil can be reinforced for increased strength, typically to the point of being impossible to tear under normal conditions;
- Compared with normal insulation, it is much easier to install; and
- A perforated option is available, which allow for vapors to escape and to enhance breathability, without compromising performance, but vapor blocking rFoil is also available.