Incandescent lamps are electrical light sources which radiate light as a result of a tungsten filament being heated to 2,600 – 3,000 Kelvin. The tungsten wire is enclosed in a sealed, gas-filled – or in some cases evacuated – glass bulb. Most of the radiation emitted is in the infrared range.

Incandescent lamps are typical thermal radiators: only around five percent of the energy they consume is converted to light; the rest is dissipated as heat. This poor luminous efficacy is the reason that Australia (2007) and New Zealand (2008) decided to ban incandescent lamps as of 2009/10. In view of the poor energy balance, the EU is also phasing out the incandescent lamp: as of 1 September 2009, a number of models will be removed from the market; the phase-out will take place in four stages. The Lighting Special "End of the incandescent lamp – The alternatives" provides details.