The Suntherm panels work on the upper limit of infrared radiation, which is close to the visible light. It is known that life would not exist on Earth without heat and light radiation provided by the sun. That is why every living organism adjust to receiving and making use of it. The importance and the effect of infrared radiation is provable easily. When being in the sun we feel warm, and, on the other hand, we feel cool in the shade, eventhough the temperature is the same. It can be observed when reptiles gain their energy from the warmth of the sun while they bask in the sun.

Energy which is accumulated in this way is reflected to the space. Every heap pours out some kind of material radiation, which orginates from the thermic movement in the structure of the material. This radiation is invisible below 525 oC and it is called infrared.

The intensity of radiation on a unit surface according to Kirchoff's law:

He = a . f /T/

a is an emission factor, which is the proportion of the radiation energy from the particular material and the absolute black body (a is always less than 100 %). It means that every thing around us has got infrared radiation. We feel it at a warm stove, at a burning fire, and sometimes we feel the lack of it (eg: at cold walls).