5.4 Directionality

Thanks to directional nature of the light emission, LEDs have higher application efficiency than other light sources in certain lighting applications.

Fluorescent and standard “bulb” shaped incandescent lamps emit light in all directions. Much of the light produced by the lamp is lost within the fixture, reabsorbed by the lamp, or escapes from the fixture in a direction that is not useful for the intended application.

Thus many fixture types, including recessed downlights, overhead general light fixtures,
and under cabinet fixtures, have lumen output ratio under 60%.