A lumen is the unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source having an intensity of one candela. There is no direct correlation between Lumens and watts because other variables may affect the relationship, such as lamp design life and fill pressure. Efficacy, given in Lumens per watt, is the total luminous flux emitted by a lamp divided by the total power input.

To purchase, please visit The Energy SuperMarket