Luminous efficacy - LED lights have the highest luminous efficacy when compared with other light sources

Luminous efficacy is a parameter that is used to explain how much of heat energy or electricity is converted to light. For simple comparison 0.3 for candle;  5 for incandescent light bulb; 46 for fluorescent bulb: 150 for LED lights. If you look at these numbers, you can see that LED lights convert the most energy to light. This means that you need to spend less electricity for the same amount of light. Small 3W LED bulbs can produce more light than  100W incandescent bulbs. When you see these calculations and numbers, you realize that LED lights save a lot of energy and money. 

LED lamp

Read more about luminous efficacy at Wikipedia ->



http://en.wikipedia.org/wiki/Luminous_efficacy