How much do you really save with compact flourescent lightbulbs?

I love the earth but admit I am a cheapskate. My palms get a little sweaty when I head to the hardware store to buy lightbulbs, and the 6-pack of compact flourescents cost $10.

So let's do the math. How much does a compact flourescent bulb really cost you, compared to a regular light bulb?

It costs $2 to use a a 13-watt compact fluorescent light bulb 6 hours a day for one year, and $18 for the typical 60-watt bulb, according to the U.S. Department of Energy. So every incandescent bulb you replace with a compact flourescent will save you $16 a year.

Sold!

Flourescents also last longer, up to 7 years, than other bulbs. Of course, they are more expensive. But in this case it looks like paying more upfront will save me cash in the long run.

It's easier when I think of each little lightbulb in the bubble package as a $16 a year bonus.

But let me be clear that I'm not going crazy buying cartloads of them either. I've read that it's best to just buy one package to start, and use it to replace the bulbs in the fixtures you use the most. I figure that's the overhead light in the bathroom, above the kitchen sink, in my bedside lamps, and the two floor lamps in the basement and living rooms. I've also read that it's good to keep a few extra on hand, and use them to replace egular light bulbs as they burn out. In theory, within a year or so, you'll have a house full of energy-sipping conpact flourescents without the expense of buying them all at once. (or wasting perfectly good, normal light bulbs.)

Looks like I have another weekend project....