What Is Lumen?

Lighting—it’s all about lumens. The Lumens definition is: "a unit of luminous flux in the International System of Units, that is equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions".
 
“Lumens” measure brightness – the higher the lumen, the brighter the light. It has been a common misconception that wattage indicates brightness. As noted above it indicates power use. A 60W incandescent light gives off roughly 700 lumens, while an ENERGY STAR 12W LED gives off a minimum of 800 lumens – similar brightness for less energy.
lumen watt