Compared with gas radiant heaters and other methods of heating which merely warm the surrounding air, the outstanding feature of halogen infrared radiant heaters, particularly as a result of their high shortwave radiation component, is that they heat bodies and objects directly.

Infrared radiation is part of the electromagnetic spectrum and is an invisible portion of natural sunlight, constituting part of the sun’s radiant heat.

Any body with a temperature above absolute zero (-273°C), for example an ice cube, emits infrared radiation. As the temperature of this body rises the wavelength of this infrared radiation decreases, i.e. the hotter the heat source, the greater the amount of infrared radiation emitted.

The shorter the wavelength of an infrared radiator the higher the proportion of short-wave radiation, and thus bodies and not just the ambient air are warmed more directly and deeply.

Medium and long-wave (depending on the distribution of the radiation) infrared emitters primarily heat the ambient air, which dissipates rapidly out of doors because of wind movement.

Solar radiation is a perfect example, consisting as it does, of UV radiation, visible light and also invisible infrared heat radiation. The positive effect of infrared heat can be illustrated simply: if we move out of the shadows into the sunlight, we feel warmer, although the air temperature remains unchanged.