A radiant barrier is very environmentally friendly, and since it saves on heating and cooling bills, it is a very green energy resource. Building experts use the term "building envelope" to refer to the entire package that keeps a house or business comfortable. This implies stopping leaks of heat, or cool air in summer, as well as blocking out unwanted heat or cold, which is where a radiant barrier is effective. There are several aspects to cooling or heating a home, and no one thing is the answer to all your utility bills. It is the combination of all of them that is most effective.
Green energy is anything that does not rely on artificial heating or cooling, or does not use up natural resources like oil, coal or wood. A radiant barrier is essentially a piece of reflecting aluminum attached to a board of some kind. It is installed to reflect heat back toward the roof. In cold climates, it is installed to reflect warm air back into the building.
Once installed it is there permanently. It never needs to be replaced. The only maintenance is to make sure there is no dust buildup, which could reduce its effectiveness. Apart from the initial installation, there is no more cost involved as long as the building exists.
Government energy websites estimate a savings of five to 10 percent on cooling bills, which is environmentally friendly as it saves energy consumption and reduces pollution to some degree. If cool air is prevented from escaping, your air conditioning unit will not have to run as much, which will make the equipment last longer, which is also environmentally friendly.
There are a lot of exaggerated claims about the effectiveness of a radiant barrier. Claims of it saving 30 to 40 percent are not realistic, and sometimes people feel it is a scam when they do not realize more than five to 10 percent, which is more realistic. There are a lot of green energy scams out there to be sure, but even with that, a radiant barrier does seem to be a reasonable part of the "envelope" of the entire building.
If it saves some energy and is not cost prohibitive, then it is a viable environmentally friendly option for cooling a home.
Also realize that the hotter it is, the more effective this barrier will be. In hot climates, the surface of a roof can be well over 100 degrees and the attic can be that as well. Reflecting some of that heat back towards the sky would be a savings on cooling. However, if you do not live in a hot climate, and there is not much heat to reflect away, the savings will be very minimal.
The environmental benefits are that it saves energy as part of the entire package of cooling a home in a hot climate. Claims are often more than reality, but in reality, there is some savings to be gained during the summer if you live in a hotter climate.