There is this theory that if you put a metallic foil behind radiators, will make them distribute heat better in the house rather than heating the wall next to them.

Is this true, are there any statistics on the issue?

If this is something that is done, what kind of materials can I use?


Statistics? I'd argue this is a misuse of the word, unless you are asking what is the fraction of photons reflected by the reflective surface. Since that truly is a probabilistic question, we could indeed compute statistics on the distribution of such reflections.

Yes, this is not just a theory. Heat is transmitted in several ways. One such way is convection. So the radiator heats the air around it, which will rise, displaced by heavier cool air from the rest of the room. These convective air currents cause a transmission of heat from the radiator into the room.

A second way that heat is transmitted is by radiation. Infrared photons will carry off energy (heat) from the radiator. Some of these photons land on the wall behind the radiator. If the wall absorbs them, then it will get warmer. So the trick is to put a reflecting surface in the way. A SHINY metallic surface is such a solution, a heat mirror. Thus a shiny metal foil will suffice. Even a regular mirror, which is simply a piece of glass with a metallized reflective back surface that reflects light, will suffice.

  • by statistics I meant gain in the use of. Like yes you should do, it will be about 10% faster to warm a room. thanks anyway – Odys Jan 29 '12 at 17:14
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    Well, I did know what you meant by "statistics". As a mathematician, I'm probably picky about words like that. :-) As far as actual numbers go, the difference will probably not be huge, since I'll bet you get more heat transferred via convective means than radiative means. Something like this can't really hurt to do, but it is also probably most easily done with the radiator not in place. And even then, my wife would probably object to how it looks, if she could see anything behind the radiator. My wife is always so picky that way. – user558 Feb 1 '12 at 11:09

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