Lights flickering: one fixture or the whole house?

A single flickering light is usually the bulb, or an LED on a dimmer it does not get along with. Flicker across many rooms is different: it can mean a loose connection on the utility's side or in the panel. Start by working out which one you have.

Also searched as: lights flickering in house, lights flickering in one room, lights flicker when ac turns on, lights dim when appliance turns on.

Before you start. If a flickering light comes with popping, crackling, a burning smell or a warm switch, turn that breaker off and call a licensed electrician.

A pendant light flickering over a kitchen island at dusk

Every question and answer on this page, in order

Question 1: Do you notice popping, crackling, a burning smell, or a warm switch near the flicker?

Touch the wall switch plate lightly with the back of your hand, and sniff near the fixture and switch.

Yes: Stop: flicker with heat, smell or noise
No: go to question 2

Question 2: How widespread is the flicker?

Walk through a few rooms with lights on.

One fixture or one lamp: go to question 3
Lights in many rooms, or the whole house: go to question 4

Question 3: With the switch off and the bulb cool, tighten the bulb or swap in a new one. Does it still flicker?

Turn it snug by hand; do not force it.

No, that fixed it: Likely cause: a loose or failing bulb
Yes, it still flickers: go to question 5

Question 4: When does the house-wide flicker happen?

Watch the lights while the AC, furnace fan, fridge or microwave starts.

Only a brief dip when a big appliance starts, then steady: Usually normal: a brief dip when a big appliance starts
On its own, in wind, often, or the neighbors see it too: Call the utility: whole-house flicker

Question 5: Is it an LED bulb on a dimmer, or LEDs mixed with other bulb types on one switch?

A dimmer has a slider, dial or rocker that sets brightness.

Yes: Likely cause: LEDs and a dimmer that don't match
No, or a new dimmable LED did not help: Likely cause: the fixture, socket or switch

Possible results

Need the words for the phone call? Build a what-to-tell-the-electrician checklist, or read when to call an electrician.