Mediumwave ir-heaters are infrared-heat sources, made of an open quartz-glass-tube, clear or translucent, a filament of a resistance wire and 2 ceramic ends. These heaters are not made by a lamp technology.

Due to the slow heat-up ( 0-100% ca 1 minute) and therefore the bad opportunity for a temperature control this type has been replaced in many industrial processes by shortwave (0-100% ca 1-2 sec) or fast mediumwave IR-lamps (0-100%, 2-4 sec). The glowing temperature of the heater is about 800°C.

In a few constant processes these heaters are still running, so the thermal dullness is not important and the price benefit is preferred.

At this heater design a reflector coating on the tube does not improve the efficiency, because the filament has direct contact to the tube, so no real radiation exists. If a little radiation would be reflected the thick filament will absorb it immediately, so not process is available.