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How to Select a Dimmer

All incandescent and halogen, and many CFL and LED bulbs are dimmable, as are LED retrofit kits. In general, CFLs and LEDs that are rated by the manufacturer as "dimmable" will dim on any residential dimmer. Incandescent bulbs, including halogen, are an inherently dimmable technology and will not say this on the package.

However, there is a wide variety of dimming performance among bulbs. Different CFL and LED products can have different dimming rates and minimum light levels, resulting in dimming characteristics that can be markedly different than what people have grown accustomed to from incandescent bulbs. Sometimes, dimming can even result in flicker and audible buzzing due to bulb or dimmer product design, or bulb-dimmer incompatibility.

Currently, there are no industry-wide dimming standards, so the best option is to use compatibility tables provided by the dimmer manufacturers and bulb manufacturers. These compatibility tables can be accessed online before purchasing the products. Selecting dimmer and bulb products that are listed as being compatible improves, but does not fully insure, the likelihood of system compatibility. (This necessitates purchasing both bulb and dimmer together. Finding a bulb that is compatible with an existing dimmer and vice versa may be more difficult.)

Check that the total power demand from the bulbs meets the minimum and maximum load requirement for the dimmer. For example, it may not be possible to dim just one LED bulb because it may be below the minimum load requirement of the dimmer.

If possible, test out the combinations of bulbs and dimmers under consideration. Be sure to meet the maximum and minimum load requirements for the test, and ideally use the same number of bulbs that will actually be installed.

Additional Information

Dimming Behaviors of LED Replacement Lamps provides more information about dimmer compatability. Presented by the ASSIST program.