According to the U.S. Department of Energy, incandescent lamps typically produce 12 to 15 lumens per watt of electric power. Compact fluorescent lamps (CFLs) produce at least 50 lumens per watt, while currently available high-brightness LEDs can produce about 30 to 35 lumens per watt.
In task-lighting applications, LEDs may be able to provide enough light on the task, even though the total lumens are less than comparable incandescent or fluorescent sources. This is because LEDs emit light in a less diffuse pattern than conventional light sources. In contrast, standard incandescent bulbs and fluorescent lamps emit light in all directions, and much of the light output is absorbed inside the fixture or escapes in an unintended direction.