Why Does My Lighting Fixture Buzz?

Clear light bulb image by simbolocoma from Fotolia.com

Electric lights are vital to our lives, keeping us happy, healthy and productive. But sometimes, they can also annoy us by buzzing loudly. Buzzing lights aren't generally a serious problem, but they can be incredibly annoying. Here's why they buzz, and what you can do about it.

Fluorescent lights

Fluorescent lights are famous for the faint buzzing sound they make. This is because each light needs a way to control the electricity flowing through the fluorescent tube, called a "ballast." The ballast creates a magnetic field that alternates the current in the wire, ensuring the light doesn't accept too much electricity. You generally find this problem on older fluorescent fixtures, which use an inductor for a ballast. Newer fixtures use a quieter electronic version.

Low voltage

If an incandescent bulb is buzzing, there can be several reasons. A common one is that the bulb is simply not getting enough voltage. If a bulb with a higher voltage is screwed into a lower-voltage socket, the resistance will make the filament vibrate as the current fights to get through the wire. The solution in this case is to simply switch in a lower-wattage bulb, which will have less resistance.

Dimmer Switches

If a bulb is buzzing and swapping it out doesn't work, check to see if it's on a dimmer switch. Dimmers essentially shut the light on and off very rapidly, and this can put a strain on some bulbs, causing the filament to vibrate. Bulbs designed for outdoor use should be able to handle being on a dimmer switch, or you can simply turn the dimmer up, which will also solve the problem.

Electrical shorts

If you've changed the bulb and put the dimmer up on full and there's still a buzz, it may not be the light bulb at all. It may be an electrical short, which is very common. Shorts can be caused by animals gnawing on wires, outdated wiring and many other factors. If the buzzing comes not from the bulb or the switch but somewhere in the ceiling or wall, you likely have an electrical short.


Only qualified electricians should change out light fixtures or look for electrical shorts. Electric safety should always be practised even when dealing with a light bulb, as there are real risks. If you're not comfortable doing something or not sure what you're doing, don't do it.