Compact Fluorescent Light Bulbs

Compact Fluorescent Light Bulbs represent the single, most cost effective, energy efficient, greenhouse gas saving device that we, as individuals, can purchase and install ourselves.

"How much can I save?"

A typical 100 watt incandescent bulb, burning for an average of 4 hours a day, will consume 400 watt-hours a day, or 146 kilowatt-hours a year (400 X 365 / 1000 watts per kW). If that bulb is replaced with a CFL lasting 7 years (a typical warantee), then for those 7 years you would have used over 1000 kilowatt-hours of power (146 X 7= 1022 kWHrs). If your cost per kWHr is $0.12, then you will have spent $120 just to keep that bulb lit. The CFL, by comparison, a 23 watt bulb with the equivalent lumens, will cost just $27, for a saving of $93. If you factor in the price of the additional incandescent bulbs and the additional HVAC load, then you save even more.

"How much CO2 will I save?"

Again, with just one bulb, you can save 787 kWHrs (1022-235). From the EIA/DOE Energy Calculator, converting kWHrs into metric tons of coal gives 0.12 tons. With an Exelon factor of 59% total energy from coal, that gives 0.07 tons of coal, or over 400 pounds CO2 PER BULB, or 60 pounds per year!

"Where does all that extra power go?"

Most of the power is used in heating the tungsten filament. In fact, incandescent bulbs could better be called "electric heaters" that happen to glow white.

"Why are our public facilities not using CFL's, knowing how much money taxpayers can save?"

You have to ask them. They'll give a good excuse.

"What are better than CFL's?"

Newer LED (light emitting diode) bulbs are now on the market that are more efficient that CFL's, but also more expensive. However, their use in traffic lights and exit signs is cost effective in many applications.