Lighting – What alternatives to R20 bulbs can I use

We have had CFL's in a number of enclosed fixtures for years now. They generate comparable light for much less heat. The main thing you need to worry about with CFLs is, you can't use them on a dimmer unless that dimmer is designed for them. Other than that - less heat means even less risk of fire in my book.

It looks like CFL bulbs are difficult to dim.

A dimmer typically reduces the effective voltage, which decreases current to the bulb. The science behind fluorescents just isn't meant to work that way, explained Paul McLellan with eLightBulbs, a division of Service Lighting, a Maple Grove, Minn., lighting supply company.

It can cause dimmer switches, or the ballast, to buzz. It can even affect other electronic devices nearby, such as radios. The distortion can even go so far as to cause flickering in the light bulb itself. Occasionally, you may be able to dim by 30 to 40 percent without any adverse reactions.

"We have looked at around 20 different brands and although some of them get close, the science is not yet there," McLellan said. "We do hear of some success, however, usually with high-quality, brand-name bulbs and dimmer switches." Sometimes it's a matter of finding which brand of bulbs works with specific dimmer switches. You may need to change the dimmer.

Remember, not all compact fluorescents are designed to work with dimmers, but CFLs made for dimmers are available. You can use regular compact fluorescent bulbs with dimmer switches, but doing so can shorten bulb life and nullify the bulb's warranty."

Taken from CFL Dimming Article