SunSwitch heaters emit virtually all of their heat energy in the shortwave infrared region, where the infrared is absorbed effectively into your body. This also means the radiant energy is not wasted heating the air. This is exactly the same way the sun heats the earth (and you) and it feels every bit as natural and comfortable. Unlike other types of radiant heater (see below) very little of the radiant heat from SunSwitch heaters is absorbed by the air. In consequence it is much more efficient as a heat source than other types of radiant heater and will cost less to run. SunSwitch infrared heaters emit exactly the same wavelengths of infrared as heat lamps used for medical and therapeutic purposes. These are extremely good for your physiology.