Definition: Lm/W

(LuMens per Watt) A measurement of luminous efficacy, which is the light output in lumens using one watt of electricity. Following is an approximate range of lumens per watt for popular light bulb technologies. The higher the number, the less costly to run the lights. See lumen, incandescent bulb, halogen bulb, fluorescent bulb and LED bulb.

 Bulb      Lumens Per 1 Watt
 Type           (Lm/W)

 Incandescent   10-18

 Halogen         9-25

 (CFL) Compact
  Fluorescent   42-75

 Fluorescent    35-125

 LED            40-200