The Incandescent Lamp Explained
What Is an Incandescent Lamp?
The incandescent lamp (also known as the light bulb) is a historic light source in which a tungsten filament is heated to incandescence by an electric current. This produces visible light with a very warm colour temperature of approximately 2,700 Kelvin and excellent colour rendering (CRI 100).
However, the incandescent lamp converted only around 5 % of the energy supplied into light – the remainder was lost as heat. Its luminous efficacy was a mere 10–15 lumens per watt. Due to this low energy efficiency, the incandescent lamp has been progressively banned in the EU since 2009 and replaced by more energy-efficient alternatives such as LED light sources.
Modern LEDs produce comparable warm white light at a fraction of the energy consumption. Thanks to technologies such as dim-to-warm, LEDs can even replicate the characteristically warm glow of incandescent light when dimmed.