Many people think that fiber glass or some other "mass" insulation is the best way to go when insulating a home or building in the South. In a way, it is for the winter months. But is a fiberglass blanket, or any other mass insulation blanket the best summer insulator? Would you wrap yourself in a heavy blanket and expect to stay cool on a 95° day, or would it make more sense to simply stand in the shade? Common sense dictates that we stand in the shade. The same basic principle applies when insulating your home, it should be a combination of acting as a good blanket in the winter and putting your house in the shade for the summer.
What is radiant barrier?
Radiant barrier is a barrier against heat transfer by radiation. Over the years, radiant barrier products evolved into what we have today, reflective foil insulations. These products consist of two layers of pure aluminum foil separated by low density material which is mostly comprised of air. Radiant barriers or reflective foil insulations made of pure aluminum foil will reflect 97% of the sun's heating energy, which, when you think about it, puts your house in the shade.
What is esulation™?
esulation™ consists of two layers of pure aluminum foil separated by low density foam air space. This construction is very similar to that of the Thermos bottle. esulation™ reflects 97% of the heat, or electromagnetic energy that hits it. The primary applications for esulation™ residentially are attics, exterior walls and under the floors of raised houses. Commercial applications are the same for wood frame buildings. It is also an excellent stand alone insulation for use in metal buildings.
In attics, esulation™ is applied to the bottom side of attic rafters, thus allowing a 5½'' air space for air to flow and reflecting 97% of the sun's energy away from the roof. As a house wrap, esulation™ is installed on the ousted of the exterior wall sheeting. It will provide a radiant barrier and a vapor barrier in this application. Installed under floors of raised houses, esulation™ provides a radiant barrier and a vapor barrier. As a radiant barrier, esulation™ will prevent heat from leaving the house in winter and from entering in the summer. It will also block the passage of humidity from the damp under floor to the interior floor space of your home. And finally, in metal buildings, esulation pro, white face, is installed directly under the metal sheets. It provides a radiant barrier and a thermal break between the metal sheet and the perlins. esulation™ will typically keep unconditioned interior temperatures in the summer at or near ambient.
How does esulation™ work?
So how does a product so thin (1/8'') do so much to reduce temperatures? The answer lies in the physical science of how heat works.
Heat is energy, and as energy, is constantly on the move. It travels from where it is to colder places in three ways, by radiation, conduction and convection. Hot air rises above colder air. esulation™ is effective in reducing heat load from radiation. Aluminum will only absorb 3% of the heat energy that hits it, thus reflecting the balance. Everything in nature either reflects or absorbs heat energy, and the total is always 100%. Objects like steel, wood, blankets and even humans absorb up to 95% of the heat energy that hits them, the other 5% is reflected. Keeping this minor physics lesson in mind, and the fact that aluminum will reflect 97% of the heat energy that hits is, you can now understand that radiant barrier is a barrier against heat transfer by radiation.