Dimmer switches can provide a more mellow feel to your home, and save electricity at the same time. But with the growing popularity of compact fluorescent lights or CFLs, many consumers are wondering what options they have for dimming these light bulbs - or whether it saves more electricity to use a regular CFL, or to use incandescent or halogen bulbs on a dimmer.

Let's start by clearing up some misconceptions people have over the relative efficiency of incandescent, halogen, and fluorescent light bulbs.

Many homeowners installed halogen lights, starting in the 1990's, on the incorrect assumption that these lights are more efficient than incandescent lamps. It turns out that their efficiency is almost the same as that of incandescent lights. So don't kid yourself that you're saving energy by using them.

Compact fluorescent lights, on the other hand, are very efficient - it takes about one fourth as much electricity to light up a CFL as to run an incandescent or halogen lamp of the same luminosity. CFLs also happen to last about eight times as long as incandescent bulbs.

So if you are using a dimmer switch mainly to save energy, you may increase your savings by just switching your incandescent or halogen bulbs to CFLs, and keeping the dimmer switch on full power, or reverting to a standard on-off switch. That will give you more light for less power.

If you want a more relaxed lighting all the time, one idea is to buy light bulbs that aren't as bright. Whether you go down from, for instance, a 100 watt incandescent to a 60 watt incandescent, or from a 100 watt incandescent to an 18 watt CFL, you'll still have less light and you'll use less electricity. Of course, the CFL solution will save you more money in the long run.

But most likely you want it both ways: the low running cost and better durability of CFLs, with the flexibility to dim them down when their full light is too bright.

Perhaps you've heard that you cannot put a regular CFL on an ordinary dimmer switch. In fact you can, but I don't recommend it, because it can really reduce the life of the bulb. You won't be adding to the risk of explosion or fire from installing a regular CFL on a standard dimmer switch - you'll only increase the risk of shortened bulb life. And since the higher price of CFLs is offset by the fact that they outlive incandescent bulbs by a ratio of 8 to 1, putting regular CFLs on a standard dimmer destroys that cost advantage.

If you choose to dim CFLs, you have two real choices: buy a dimmer that is compatible with fluorescent lights, or buy so called dimmable CFLs that are designed to work with standard dimmers.

Both alternatives give you the energy-saving benefits of compact fluorescent lights, along with the ability to dim those lights. But for the time being, dimmable CFLs seem like the more affordable option, because fluorescent-compatible dimmer switches are very expensive, while the price gap between standard and dimmable compact fluorescents is just pennies.

Let's consider the total cost for both alternatives, for a lamp with three 60-watt bulbs. Let's assume you already have a standard dimmer switch and regular incandescent light bulbs. If you want to upgrade to CFLs, your choices are:

1. Putting in three 13-watt standard CFLs at $3 a piece, and a $49 fluorescent-compatible dimmer switch. Total cost: $58.

2. Putting in three 13-watt dimmable CFLs at $3.50 each, and use the existing dimmer switch. Total cost: $10.50!

As you can see, using an existing dimmer is a more affordable solution. Since both options use the same amount of electricity, in terms of payback period the second solution with dimmable compact fluorescent lights is definitely going to pay for itself sooner.

Even if you have to get a dimmer switch anyway, it is still better to buy a standard switch and dimmable CFLs. You can buy a standard dimmer switch for under $10. Even a high fashion one for $25 is cheaper than a fluorescent dimmer at $49. And with the cost difference between standard and dimmable CFLs so narrow, the only way a fluorescent dimmer switch can become cost competitive is if the price on it drops considerably, which it probably will over the next few years.

If your only objective for using a dimmer switch with CFLs is to save money, and you don't already have a regular dimmer switch, I suggest you stay with basic CFLs for now and forget about the dimmer switch. Use the money you save on the dimmer switch to purchase more compact fluorescent lights for other areas of your home. Dimmer switches added up to big savings for halogen or incandescent lights because the bulbs were so inefficient. For example, my basement rec room has six 50-watt bulbs on a dimmer switch. By using the dimmer at about half power, we use 150 watts instead of the full 300 watts. Given an hour of use each day, that saves us 150 x 365 watts, or 55 kilowatt hours a year.

But if we were to upgrade those halogen bulbs to 13-watt dimmable CFLs, we'd save 81 kilowatt hours a year at their full strength. By turning them down to half, we'd only save an additional 13 kilowatt hours a year - that's about $1.30 worth of electricity. Not really enough to justify seriously considering this alternative.

Consumer response to dimmable CFLs has been mixed. There were definitely some teething problems with these lights - fast burn-out, flashing light, and loud buzzing noises. These problems have been largely resolved in the newer dimmable compact fluorescents. But if there isn't a compelling reason for you to dim your CFLs, I would recommend sticking with standard CFLs for a year, until the market offers a wider range of choices for dimmable fluorescent lights. You never know - in a year or two, fluorescent dimmer switches may drop in price as well.