I plan to start using CFL's in an effort to both lower my electric bill and become more green at the same time.

I've heard that it doesn't make sense to get rid of a paid off car to replace it with one that has better fuel efficiency. Is the same true for cfl's? Does it make sense to replace still useful bulbs with cfl's or does it make more financial sense to wait until bulbs need replacing and switch then?

Given that CFLs use so much less electricity than conventional incandescents, and given that the purchase price is relatively low, it makes sense to switch now even if your existing bulbs still have life in them. You can keep the incandescents as spares.

A few places where CFLs don't make sense:

1. closets (unless you're in the habit of forgetting to turn off your closet light and leaving it on for weeks at a time!)

2. dimmers, unless your store carries CFLs that will work on dimmer switches...they are available but not every store carries them.

3. Outdoor fixtures in really cold climates...I've noticed that CFLs can remain very dim in outdoor fixtures when the temp is below zero.

Also note that you may have to buy a new harp or harp extenders for table lamps when you install CFLs...on my lamps the top of the bulb ended up scraping against the harp. Harp extenders or a new harp would do the trick.

Hmm, well doesn't that figure. The lights that we use the most (in a great room where we do the vast majority of living) are on dimmers. And we really do use the dimmer feature. I'll have to check around to see if I can find the dimmer specific ones.

oasn: I just realized that we have no lamps. All of our lighting is hardwired into our home.

We swapped them out all at once. Aside from the monetary savings, it's a great way to reduce your carbon footprint.

I'm doing one a week. Small enough amount that I don't notice it.

I have to disagree on the idea of not putting them in closets for 2 reasons. The first is that in my house, the closet is the light most likely to be left on and forgotten behind a closed closet door. The other one is that most fixtures these days are limited to 60W bulbs for heat and fire reasons. Since CFLs use a fraction of the wattage, and generate less than 1/3 of the heat, you can put a much brighter bulb in the fixture than you can with an incandescent. That's very helpful with closets in my house.

I replaced our highest use lights first. In our kitchen, we used to always have one small lamp, the light in the range hood and the two recessed lights over the counter/bar area on almost all the time. Replacing them with CFLs took the 255 watts down to 60. Can't argue with that.

The first reason is indeed a good one...my former landlady was forever leaving closet lights on, for weeks at a time. But if you generally leave your closet light on for only a few minutes a day, it could take many years for a compact fluorescent to pay for itself--perhaps even longer than the bulb's life. However, a Croz points out, it's not just an economic decision: you may have other reasons to want to use CFLs in there.