In the past dimmers were mainly used to control indoor traditional incandescent light bulbs and helped to save energy. When dimming a compact fluorescent bulb (CFL), or a LED bulb, you should know not all dimmers are created equal. Using a traditional dimmer switch may or may not work with the CFLs or the LEDs you are using.
Dimmable CFLs will be noted as such on the packaging. These CFLs are built with a special ballast to allow dimming. Using a non-dimmable CFL with a dimmer will damage the bulb and cause premature failure.
When dimming LEDs, be mindful that your existing dimmer may not dim low enough and will shut off the LED bulb before you get to the lowest setting on the dimmer switch. If the LED does “drop out,” it may not work immediately when you try to restore its brightness. In this case you will need to shut it off and then turn it on again. Purchasing an LED dimmer should correct this issue.
Consult your local lighting technician or home improvement store for specific questions about your particular need.