Short wave infrared radiation is produced which can be accurately directed to a specific area and is effective over a considerable distance from the heater. The radiant energy produced is not absorbed by the air through which the lamp beam is directed and heat is only apparent when it warms a surface or solid object.
Lamps are available in a range of heaters of various designs.
Most lamps have ruby red filters to reduce the white light emitted and increase the infrared component. One of the key advantages of a quartz heater is that it operates at the flick of a switch and reaches full output within a second. This factor makes them very energy efficient in their use since heat is provided only when it is needed. When used without a ruby filter, both heat and light can be produced. This enables lamps to be used for applications such as seed propagation.