LED light bulbs can be used in light fixtures controlled by dimmer switches, but you may well find that traditional dimmers may not work—or may work inadequately—with some LED bulbs. The bottom line is compatibility. Some LED bulbs are designed for use with standard dimmer switches, while others are not. Some fixtures, such as under cabinet and recessed lights, may need special LED dimmer switches for proper performance.
Conventional incandescent light bulbs are compatible with most types of dimmer switches and are adjustable to almost zero light output. By contrast, many LED bulbs won't work with standard dimmer switches—the kind you most likely have in your house. Even dimmer-compatible LED bulbs typically can't be dimmed as low as incandescent lights when they are paired with standard dimmer switches—they may dim the light down to about 30 percent of full illuminations, and they then turn off completely. Traditional dimmer switches require a minimum wattage to operate correctly, and for this reason, they may not work at all with LED bulbs. If you find this, the only option is the replace the dimmer switch with one designed to work with LED bulbs.
Another difference between LEDs and incandescent bulbs is in the color temperature, or the perceived warmth of the light as they dim. Incandescent bulbs tend to emit a warmer, softer glow as they dim, but with LEDs, the color temperature doesn't change with dimming, so you may not get the softer ambiance you're looking for. Some LED products, however, simulate this effect by combining diodes of different color temperatures in the same bulb.
The easiest way to put an LED light bulb on a dimmer circuit is to use a bulb that's compatible with standard (incandescent) dimmers. Start with one bulb and see how well it works on your dimmer. Try another brand and type if the first one doesn't work.
Another option is to replace your old dimmer switch with a LED-compatible dimmer. This still requires a dimmable LED bulb, but it's likely to provide better dimming performance than a dimmable bulb on a standard switch.
If you have LED under-cabinet or recessed fixtures, you may need an electronic low-voltage dimmer (ELV) or a magnetic low-voltage dimmer (MLV). Check the light bulb or fixture packaging or contact the fixture manufacturer or retailer for recommendations. Many manufacturers and retailers have online compatibility charts to help consumers match specific switches and bulbs or fixtures.
Is It Worth the Switch?
Given the need to pair dimmers and LED bulbs that are compatible with each other, you may be wondering if making the switch is worth the effort. It undoubtedly is. LED bulbs produce a large amount of light using much less power, reducing your electric bill. Creating a bright 2,600 lumens of light, for example, requires an incandescent light that uses 150 watts of power. You can achieve the same amount of light with an LED bulb while using only 25 to 28 watts of power.
So LED bulbs are indeed worth buying, but is it really worth upgrading your dimmer switch? The answer is, once again, yes. LED bulbs have a much longer useful life than incandescents and last 20 years or more. A proper match between the dimmer and bulb will not only improve dimming performance but may increase the life of the bulb. When properly matched to the right dimmer, LED bulbs are also much less likely to generate the annoying humming noises that occur when you dim traditional bulbs or mismatched LEDs. Matching an LED bulb with a compatible dimmer switch will give you better all-around performance, and over years will easily recoup the money you spend on the new dimmer switch.