Changes

LEDs have had a very high profile in the energy market for some time. But until recently they did very poorly in energy efficiency. Fluorescents were best, producing about 30-100 lumens per watt, while halogens produced 10-18, and incandescents 8-15.

Before 2007, LEDs used less than 10% of the energy of an incandescent lamp, but did not produce as much light output per watt of energy consumed. To disguise this, some vendors rated LED efficiency as the amount of light output generated per watt of total output energy instead of the input energy.