What usually causes this?
Dimmer incompatibility
Older dimmers can't smoothly control LED bulbs, causing buzz and flicker.
Failing ballast or driver
Fluorescent ballasts and some LED drivers hum as they age.
Loose bulb or parts
Loose bulbs, shades or fixture parts can vibrate.
Loose wiring
Loose connections at the fixture or switch can buzz and heat up.
Overloaded dimmer
Too many fixtures on one dimmer can overload it.
What you can safely check
These details help an electrician find the cause faster. Look and listen only — do not remove covers or touch wiring.
- Is the buzz from the fixture, bulb or switch?
- Does it stop at full brightness?
- Is the switch or dimmer warm?
- Does flicker accompany the buzz?
- Type of bulb and fixture
Warning signs that need a professional
- Switch or fixture is hot
- Burning smell
- Scorch marks at the fixture or switch
- Buzzing plus flickering across rooms
- Sparks at the switch
When should you call an electrician?
If changing bulbs or using compatible dimmers doesn't stop the buzz, or if the switch or fixture gets warm, call an electrician to inspect the connections, dimmer rating and fixture components.
Services that fix this problem
Light Switch Installation
Installing and replacing switches, dimmers, three-way and four-way switches, timers and smart switches.
Lighting Installation
Installing and upgrading light fixtures, recessed lighting, under-cabinet and outdoor lighting in your home.
Electrical Repair
Diagnosis and repair of dead circuits, failing outlets and switches, tripping breakers and other everyday electrical faults in your home.
Indoor Lighting
Interior lighting design and installation — kitchen, living room, bathroom, closet, hallway and stair lighting.
Related electrical problems
Frequently asked questions
Many older dimmers aren't designed for LED loads. An LED-rated dimmer usually fixes it.
Buzzing from bulbs or dimmer mismatch is usually a nuisance. Buzzing with heat or smell may indicate a loose connection that needs attention.
Fluorescent ballasts often hum as they age. Replacing the ballast or converting to LED is common.