Comparing Lumens per watt- The TRUE measuring stick of efficiency

Yesterday, the question arose, "what is the most efficient lighting source available?" The person continued by asking if it's LED yet, or is it still High Pressure Sodium.

For the novice, first let me provide a definition of Lumens per watt, which will be the measuring stick for efficiency. Lumens per watt is defined as "A measure of the efficiency of lamps. It indicates the amount of light emitted by the lamp for each unit of electrical power used". For example, a 100-watt lamp producing 1750 lumens gives 17.5 lumens per watt.

So, I wanted to provide a chart comparing different lighting technologies for you to easily see the differences. However, manufacturer's produce different products which makes it hard to put an exact number down. It is a lot like the gas mileage you get with a car. It is very difficult to say all 4-door sedans get 20 mpg. With that said, here is chart:

Incandescent- 24 lumens per watt
Halogen- 36 lumens per watt
Compact Fluorescent(CFL)- 80 lumens per watt
Fluorescent Tubes- 105 lumens per watt
Ceramic Metal Halide- 125 lumens per watt
High Pressure Sodium- 140 lumens per watt
Low Pressure Sodium- 180 lumens per watt
LED 200 lumens per watt

Does this mean you should change every light fixture in your facility to LED? Whoa, no way. LED has it's benefits and in certain applications it is terrific..in others, however, LED technology may not be the best option. Every area should be addressed individually to best maximize light levels, energy-savings and employee performance.