Halogen lamps are a further development of the incandescent lamp. They generate light in the same way (as a thermal radiator) but are a more efficient light source in terms of energy consumption (luminous efficacy up to 25 lumen/watt) and life (2,000 to 4.000 hours).

There are high-voltage halogen lamps (for 230 V line voltage) and low-voltage halogen lamps (for 6, 12 or 24 V) available. Less efficient halogen lamps (except reflector lamps) are covered by the regulation "Domestic Lighting, Part 1". The incandescent lamp can be replaced in a straight swap by high-voltage halogen lamps with E14 or E27 base. As of 1 September 2009, however, such replacements will have to be clear models. High-voltage halogen lamps have the same brilliance as incandescent lamps and can be similarly dimmed.

Filling gas additives

Halogen lamps are filled with halogen gas. The additive ensures that the tungsten atoms that evaporate from the filament are re-deposited on the filament in a cyclical process. This prevents blackening of the bulb and extends the life of the filament and the lamp as a whole.

Energy-optimised high-voltage halogen lamps with screw base save 30 to 50 percent energy in comparison to an incandescent lamp. Their filling gas is additionally mixed with inert gases. Models with lower power ratings than an incandescent lamp can be used with no loss of luminous flux. The table below shows the replacement options.