Contrary to common belief, wattage isn't an indication of brightness, but a measurement of how much energy consumed by a light source ( or other electronic device ) .Brightness is measured in lumens.
To produce similar amounts of light, LED lights consume far fewer watts than incandescent or halogen bulbs.
For example a standard 60W incandescent produces 800 lumens, whereas 10-12 W LED also produces 800 lumens.
As you can see in the chart above, an incandescent can draw up to eight times as many watts for the same number of lumens, as compared to a LED light source.