Incandescent lamps are thermal radiators. In an enclosed bulb filled with gas, an electric current is passed through a filament of tungsten wire to make it glow. With this method of generating light only about 5% of the energy consumed is converted into light, the rest is lost as heat.  

SUPERLUX KRYPTON lamps from OSRAM are incandescent lamps with up to 10 % higher luminous efficacy than conventional light bulbs. In other words, they generate up to 10 % more light from the same power consumption.  

Incandescent lamps can be dimmed to any level and will last around 1000 hours on average. This corresponds to about one year for normal household usage of three hours a day.