Lighting & ceiling fans

Lights flicker or flash on a dimmer

Flickering specifically tied to a dimmer setting is almost always a bulb-dimmer compatibility issue, most common with LEDs on older or mismatched dimmers.

Difficulty
Easy
Time
15–30 minutes
DIY cost
$15–$35
Pro cost
$100–$180

Symptoms

  • Flicker appears mainly at low dimmer settings
  • Flicker changes as you slide or rotate the dimmer
  • Different bulbs behave differently on the same dimmer

Likely causes

  • CommonNon-dimmable LED bulb installed on a dimmer circuitStandard, non-dimmable LEDs can flicker or behave erratically on any dimmer.
  • CommonDimmer type mismatched to bulb typeOlder leading-edge dimmers work poorly with many LED bulbs, which often need trailing-edge or LED-specific dimmers.
  • PossibleToo few bulbs for the dimmer's minimum loadLED wattages are often below what older dimmers were designed to handle smoothly.
  • PossibleMixing bulb brands or models on the same dimmerDifferent LED drivers can behave inconsistently together on one dimmer.

What to do

  1. Confirm every bulb on that dimmer is labeled dimmable.
  2. Use the same brand and model of bulb throughout the fixture if it currently has a mix.
  3. Check the dimmer's specification for LED compatibility and minimum wattage.
  4. Replace the dimmer with an LED-specific model if it's an older incandescent-style dimmer.
  5. Test at different dimmer positions to see if flicker is limited to a certain range.
  6. Try a known-good, high-quality dimmable LED bulb as a test.
  7. Call an electrician if flicker continues with matched, quality bulbs and an LED-rated dimmer.

Tools and parts

Trailing-edge LED dimmerSearch: “trailing edge LED dimmer switch”

When to call a pro

Call an electrician if flicker persists after matching bulbs and dimmer type, since it could point to a wiring issue.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.