An infrared lamp is a tungsten-filament lamp primarily designed to produce radiant heat (infrared energy) rather than visible light. The filament, which is sealed in a gas-filled bulb or quartz tube, is heated by an electric current and operated at a temperature of 4000°F (2200°C) to produce an abundance of infrared energy at wavelengths that readily pass through glass or quartz. The lamp may have a metal reflector on its inside or outside surface to concentrate the radiant heat output. Infrared lamps are available in ratings from 250 to 1,000 watts; they have a life of nearly 5,000 hours.
Infrared lamps are widely used as heat sources in industry for processing products such as ceramics, metals, paper, textiles, and leather. They also are sold for therapeutic use at home for deep muscle therapy.