LEDs have greater lighting efficiency than incandescent and fluorescent lights. This means that more of the electrical energy going into LED lighting is converted into light while less turns into heat. This is why they are cooler than other types of lighting. However, comparing its light output to electrical power input is just part of the picture.
Another property of LED lighting that saves energy is its unidirectional light. Unidirectional means that the LED’s light moves in a single direction as opposed to the omni directional light of fluorescent tubes that radiate light in all directions.
Why does unidirectional light save energy? Because if you are trying to illuminate an area below the light such as a work table in an office or on a factory floor, most of the light output from the LED source is illuminating the work table.
By contrast, a lot of the omni directional light from a fluorescent tube doesn’t reach the work table. Of course, they do have reflectors on their topside to direct more of the tube’s light downward. But the reflector is crude and doesn’t do a good job of this. To achieve the same table illumination (measured in lumens), you would need a stronger fluorescent light that puts out more light (overall) so that the small fraction reaching the table gives it the same illumination level as the LED light.
Therefore, the omni directional light property of fluorescent tubes is a kind of energy inefficiency because the light that shines in the other directions is wasted energy. Of course, if your intent is to illuminate a wide area with diffuse light, then unidirectional LED lighting is less optimal.
However, LED flood lights are available, which have special optics that produce the same omni directional light of fluorescent lights. Because LED lighting uses less power to achieve the same illumination output, they still outperform fluorescent lighting for this purpose.
