Purchase LED bulbs!
The “Sustainable Energy–Science and Application” class did the research for you. Here is why you should use LEDs:
- The most energy efficient bulb on the market
- 18 Watts – 82% more efficient that 100W incandescent
- Use less that 20% of the energy required by an incandescent
- 25,000 hour average operating life which is 33 times that of a conventional incandescent bulb. This is over a 20-year lifespan if you use the bulb an average of 3 hours a day
- No mercury!
- Omni directional and dimmable
- 10-year warranty
- LED :: 88.9 % efficient, lifespan 25,000 hours
- CFL (fluorescent) :: 69.6 % efficient, lifespan 12,000 hours
Incandescent :: 16.9 % efficient, lifespan 750 hours
The economics for purchasing an LED replacement “100W” bulb:
Assume the bulb is used 3 hours a day on average and that electricity is 0.1$/kWhr. Over one year this bulb uses 3 hours/day * 365 days * 0.10 $/1000Whr = 0.11$/W. In one year the bulb is on 1095 hours. So over 1 year you will need 2 incandescent bulbs and over 20 years you will need 29 incandescent bulbs (1095 hours/year * 20years / 750 hours per bulb).
1-year : Purchase Cost + Operating Cost
- Incandescent: $1/bulb * 2 bulbs + 0.11$/W*100W = 13 $
- LED : $12/bulb + 0.11$/W*18W = 14 $
20-year: Purchase Cost + Operating Cost
- Incandescent: $1/bulb * 29 bulbs + 0.11$/W*100W *20 years = 249 $
- LED : $12/bulb + 0.11$/W*18W * 20 years = 52 $
You basically break even in your investment in 1 year and save almost $200 over 20 years. If you replace 12 bulbs like this in your house you will save roughly $10 per month. This is an impressive savings for an easy switch!
Bulbs can be purchased during Earth Day! (or through the Department of Physics and Astronomy. See attached flyer for details.)