This calculator helps you determine the dollar amount of energy savings you will realize if you substitute compact fluorescent bulbs for your regular incandescent bulbs in your house. Your fundraiser may not offer all of these bulbs, so this calculation will be approximate but it gives you an idea of what you can accomplish.
When entering your cost per kilowatt Hour of electricity, you should use your highest rate to make this accurate. (some utilities use a sliding rate structure that charges you more if you use more.)
When ready, press the Calculate button to determine your savings.
Note: If you want a printed form to use to calculate your energy savings by hand, use our printed Savings Calculator.
Should I replace my old bulbs now if they still work?
The answer may surprise you. From a purely energy savings and total cost savings, the answer is normally YES for several reasons:
The normal lifetime of an incandescent lightbulb is 1,000 hours. Assuming that your 100-watt bulb is brand new, it will consume 100 kilowatt hours until it burns out. At $.09/kwh, this will cost you at least $9.00 (it could be $25 or more depending on your utility rates.)
A replacement CFL bulb will cost you less than $5.00 and its energy usage during the same 1,000 hours will only cost you $2.07. Thus, you clearly come out ahead during the first 1,000 hours. After that, you will continue to spend only $2.07 for each 1000 hours of use as compared to the $9.00 you were spending. And you avoid the extra cost of $1.00 or so for a new incandescent bulb each 1000 hours.
You don't have to throw your old bulbs away. Most likely, you will not replace (nor should you) working bulbs in places of low usage like closets or rooms that are never used. Save your old bulbs to replace those bulbs when they burn out. When you have used up all your old bulbs, then you can buy new fluorescent bulbs.
