Scientific American had an article on the costs of light bulbs1. I wanted to figure out a way to fairly compare the rough lifecycle costs of the bulbs to the consumer. I figured the best way to do that would be to determine the cost per an operating lux-hour.
We’re going to figure out the cost to buy and operate lights that emits 1600 lumens for 20000 hours given that energy costs 2:
Cost of energy:
Cost of bulbs:
You can do the same math for the rest of the bulbs (substituting the proper numbers in) to get a chart that looks like this:
|Life span (hours)||750||1000||10000||20000|
|Cost to run||$170.00||$130.90||$39.10||$34.00|
|Cost to buy||$9.87||$31.80||$4.46||$45.00|
Here’s the thing I found amazing: there’s a big push to implement LEDs, probably because of the ‘cool’ factor. However, they don’t save that much more energy over CFL — about 13% — and they cost almost twice as much to operate right now. Manufacturers are going to have to have to drop the cost of LED lights a lot in order to make a change worth it…or the government will have to ban mercury in lights3.
Graphic by George Retseck and Jen Christiansen
Sources: U.S. Department of Energy and Efficacy calculations based on currently available bulbs (traditional, halogen and compact fluorescent); SWITCH LIGHTING (led)
How to Buy a Better Lightbulb, John Matson, Scientific American, January 6, 2012 ↩
CFLs contain about 4mg of Mg, per Energy Star ↩