This is a follow up to my post of yesterday about cool roofing material. The cool roofing shingles are a form of radiant barrier.
First, a little background material.
There are two primary ways heat travels.
Conduction is when heat travels through a material. When you turn on your furnace and hot air comes out your registers, that is an example of conduction. The heat conducts through the air (and the paint, and the sheet rock, and the studs, etc, etc). Standard bat or blown insulation is specific intended to slow down heat loss through conduction.
Radiation (not to be confused with radioactivity which is something completely different) is when the heat travels the way light travels, as electromagnetic radiation. When you go outside and feel the warmth of the sun on your face, you are experiencing a benefit of radiation.
Radiant barriers are barriers to the transfer of radiant energy.
The sun shines on your house every time the sun shines. This heats your house. The effect of this is not insignificant. When your attic is hotter, your home is hotter. You can cool your home in hot weather by installing a reflective material which acts as a radiant barrier.
Radiant barriers come in various forms:
- Cool roof shingles contains reflective material built into the shingle
- There is a heavy duty tin foil type product that can be staples in the attic, to the undersides of the rafters.
- There are now even radiant barrier additives for paint.
Radiant barriers work! That is why you should care. They keep homes cooler in hot weather and reduce the need for air conditioning.
So the next time you are doing some form of home maintenance or upgrade, be it having your roof replaced, painting your home, or turning your attic into more a more usable storage space, consider doing some form of radiant barrier. The incremental cost is minimal, and the increased comfort in the home is significant, and radiant barriers are available in more and more products which are not in and of themselves insulation.
There is however one important caution. Sometimes bathroom exhaust fans vent into the attic, rather than the outside of the home as they should. When you install a radiant barrier, you MUST ensure your exhaust fan vents to the outside. In general you do not want the moist bathroom exhaust air sitting in the attic, and you want it even less after you install a radiant barrier. They do breath (they have lots of little holes in them) but not as well as the attic does without one.
Try a radiant barrier! You’ll like it.