Q: Are CFL bulbs dimmable?
Yes, but CFL bulbs must be designed to work on a dimming circuit. Due to the more demanding circuitry, dimmable CFLs are more expensive than standard CFLs. Dimming for incandescent bulbs works by reducing the amount of power sent to the bulb, which is not recommended to CFL bulbs.
Reducing the amount of power to a CFL bulb can keep its filament from getting a sufficient amount of heat to function correctly and the CFL bulb will not achieve the full life.
Dimming CFL bulbs have a ballast which is placed in the ceramic between the bulb and the socket. The ballast will allow sufficient heating to the filament and will have no effect on the life of a CFL bulb.
The dimmer control used in combination with dimmable CFL bulbs needs to be matched to the range of its power use. CFL bulbs commonly draw power in the range 7-20 W while many dimmers intended for use with incandescent bulbs do not perform adequately below 40 W.
In a table below, the most common types of CFL bulbs are listed. As you can see, for each CFL type a dimmable version is available.
|Most Common CFL Types||Dimmable version available (Yes/No)|
|Spiral Compact Fluorescent||Yes|
|Globe Compact Fluorescent||Yes|
|Torpedo & Flame Tip||Yes|
|2-Pin Double Tube||Yes (dimming ballast)|
|4-Pin Double Tube||Yes (dimming ballast)|
|4-Pin Triple Tube||Yes (dimming ballast)|
|Single Tube||Yes (dimming ballast)|
|Circline||Yes (dimming ballast)|