Here's a cool calculation that I found from Kira Marchenese's blog over at Green Options.
How much savings CFLs rack up
Crunching the numbers is eye-opening. Let's compare a 25-watt CFL costing $3 (a good average price) to a 60-cent, 75-watt IC.
Now, let's turn on both our 10,000-hour CFL and our 750-hour IC bulb at 12:01 a.m. on January 1 and keep them running 24/7 for a year. On December 31, our CFL has racked up extraordinary savings in cash and pollution.
| 75-watt IC | CFL | Notes | |
|---|---|---|---|
| Initial cost | .60 * 12= $7.2 | $3.00 | Because the IC bulb only lasts 750 hours, we’ve had to buy 12 of them. The CFL, on the other hand, has over 1,000 hours left. |
| Energy used | 657 kWh | 219 kWh | |
| Energy costs (.10/kWh) |
$65.70 | $21.90 | Oh, to have this electricity rate! Very few places in the U.S. are so lucky. (Check your bill to compare your rate.) |
| Energy costs (.20/kWH) |
$131.40 | $43.80 | Here's a more realistic energy rate. |
| Carbon dioxide (CO2) pollution | 880 lbs | 293 lbs | These calculations use the national average of 1.34 pounds CO2 per kWh. State averages vary widely [PDF], from 0.03 (Vermont) to 2.24 (North Dakota). |
| Total savings from the CFL: $48-$91.80 and 587 lbs of CO2 | |||
(Read the rest of the post over at Green Options)
