Dimmer switches can be installed on lamps and wall light switches to allow the light to be dimmed rather than just turned on and off. Dimmers are available in a variety of styles, such as a dimmer knob or a slider switch. Regardless of the type of dimmer installed, a frequent complaint is that the switches or lights emit a buzzing sound after installation. Although the buzzing sound may worry homeowners, fixing it is a very simple task.
Turn off the light, if it is currently on, and allow the light bulb to cool down.
Remove the light bulb from the light and replace it with a lower wattage bulb. Some dimmers emit a buzzing sound when light bulbs are near the maximum wattage for the dimmer, as specified on the dimmer packaging. This is especially true in fixtures with multiple bulbs. Replacing all of the bulbs with a lower wattage will often stop the buzzing sound.
Turn the light back on and then adjust the dimmer switch to see if the buzzing has stopped. If the buzzing is still present, additional troubleshooting is required.
Turn the light off, remove the bulb and insert a rough service bulb. A rough service bulb is a more durable light bulb frequently used in appliances and heavy duty work lights. These bulbs are more durable than standard household lights and the filament will not vibrate, which can sometimes cause the buzzing sound. If you cannot find a rough service bulb, you can substitute a 130 volt light bulb.
Turn the light back on and the buzzing noise should be gone.
You can purchase rough service bulbs and 130 volt bulbs at home improvement, hardware and automotive supply stores. If the lower wattage bulbs and rough service bulbs do not fix the buzzing sound, replace the dimmer with a higher grade dimmer containing an LC filter. The L stands for inductance and the C stands for capacitance, however, the packaging on the dimmer will simply say LC filter.