Light Bulb Technology: Update I

Earlier this week I mentioned that I had come across the three types of light bulbs at Home Depot.  I bought one of each:

  • 40 Watt incandescent
  • 40 Watt CFL
  • 40 Watt LED

I’m gonna try and see how big the difference is between the three and how long the payback period is for switching.

I started with the incandescent bulb and let it burn for 72 hours.  When I turned off the lamp at that time, the bulb had consumed 2.93 KWH.  At 17.01 cents per KWH, that bulb cost me $0.498 to run for those three days.  Or .7 cents per  hour.  The bulb itself cost me $1.00.  Further, the life of the bulb is listed as 2,000 hours.

Here’s what it looks like:

Bulb Cost per Bulb Cost per KWH Cost per hour Lifespan 50,000 Hour Cost
Incandescent $1.00 $0.1701 $0.0070 2000 $375.00

I’m using a 50,000 hour cost because the LED bulbs are rated for 25,000 hours. Imagine, 25,000 hours. THAT is a long time.

One response to “Light Bulb Technology: Update I

  1. Ten years ago I installed several inexpensive light fixtures with 100 watt incandescent bulbs in dark corners of my garage. None of these lights are used more than a few minutes at a time. I could switch to more energy efficient bulbs, but I would never reach a break even point because I do not use the lights enough. There are places that I use energy efficient bulbs; there are also places in my home, garage, and barn that are best served with incandescent bulbs.

    Three months ago the local home improvement store had a sale on incandescent bulbs. I bought four cases of assorted sizes from 40 to 100 watts. A co-worker’s husband did the same thing. He jokes that he will list his bulbs in his will so that after his dies, any remaining incandescent bulbs can be pass on to his heirs.

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