LEDs emit light in a certain direction while the incandescent lamps and fluorescent lamps emit light and heat in all directions. For lighting applications which will use a directional light, LEDs are much more effective and energy-efficient.
For example, an incandescent lamp or a compact fluorescent lamp (CFL) used in the lamp built into the ceiling will be wasting about half of the emitted light. In the case when LED lights are built into the ceiling, they emit light only in the direction where it is needed, i.e. the room below the lamp.
An incandescence lamp produces light by conducting current in a metal filament that heats up to such high temperatures that it starts glowing. Incandescent lamps emit 90% of the electricity consumed in the form of heat.
In fluorescent lamps the current flows through the fluorescent tube containing a variety of gases. This reaction causes the emission of ultraviolet (UV), which is converted to white, visible light by a fluorescent coating (called phosphorus), which is located on the inner walls of the tube. Fluorescent lamps emit about 80% of consumed electricity as heat.
LED lamps use light-emitting diodes (LEDs) to produce light in a very efficient manner. The movement of electrons in a semiconductor structure emits light in small electronic components known as LEDs. A small amount of heat which is produced in the diode structure is transferred from the back of the semiconductor to the heat sink.
Well-designed LED lighting is more energy-efficient, durable, versatile and has longer lifetime as compared with incandescent and fluorescent lamps.