Answer: Yes, I use them in my lights (see photo). Just like new fixtures, older fixtures were designed to handle up to a certain wattage bulb, usually 40, 60 or 100 watts. Compact fluorescent lightbulbs use far fewer watts than standard incandescent bulbs to deliver the same amount of light. For example, you can replace a 60-watt incandescent with a 13 to 15 watt CFL. In addition to saving you about six dollars per year per bulb, CFLs also burn cooler so there should be no problem overtaxing your older fixture. Plus CFLs last much longer, so you won’t have to replace them as often.  That’s especially nice if you have to remove fragile or hard-to-replace covers on your old fixture to replace the bulb. (In my house that's my job, so it’s my fault if anything breaks.)

Before you go shopping, measure the height of the shade. You may need to use a micro CFL so that the bulb doesn’t stick out. Or you can buy a covered CFL, but our tests of CFLs have found that these may not be as bright so you might need a slightly higher watt CFL.

—Celia Kuperszmid Lehrman