The lumen per Watt (lm/W) indicates how much light (lumens) a lamp produces per Watt of energy consumed. This number shows how efficient a lamp is.

LED lamps are very efficient, producing on average over 100 lumens per Watt, providing a lot of light while using relatively little energy. In comparison, a traditional incandescent bulb produces only about 10–15 lumens per Watt.

A higher lm/W value means more light with less energy, resulting in lower energy costs and a sustainable benefit for the environment.