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True Trade Path

Diagnostic guide

Lights Flickering

Lights that flicker or dim — determine whether it is a loose bulb, an overloaded circuit, or a problem at the panel.

System
Electrical
Causes covered
7
You can check
3 without a technician

Stop and read this first

  • Flickering throughout the house with simultaneous brightening and dimming means call an electrician today — loose neutral.
  • A warm switch, outlet, or panel means shut off the circuit and call immediately.
  • Do not ignore persistent flickering — loose connections cause electrical fires.

Work through these in order

Ordered from most to least likely. Working top down means you rule out the cheap, common causes before paying anyone to look at the expensive, rare ones.

  1. Loose or failing light bulb

    CommonYou can check
    How to check
    One fixture flickers. Bulb is not seated firmly or is at end of life.
    The fix
    Tighten the bulb. Replace with a new bulb. For recessed lights, check that the socket tab is making contact.

  2. Circuit overload when large appliance starts

    CommonYou can check
    How to check
    Lights dim briefly when the AC, microwave, or dryer starts. Flickering is brief and predictable.
    The fix
    Move high-draw devices to a different circuit if possible. A 15A circuit handles about 1,440 watts continuously.

  3. Loose connection at a switch or outlet

    CommonNeeds a pro
    How to check
    Flickering affects multiple lights on the same circuit. A switch or outlet on the circuit feels warm.
    The fix
    An electrician checks and tightens connections. Loose connections are a fire hazard — do not ignore them.

  4. Voltage fluctuation from utility

    PossibleNeeds a pro
    How to check
    Neighbors report the same issue. Flickering occurs at random times, not tied to appliance use.
    The fix
    Contact the utility. A failing transformer or undersized service drop on your street causes voltage sag.

  5. Failing LED driver or incompatible dimmer

    PossibleYou can check
    How to check
    Flickering on LED bulbs only. Started after switching to LEDs or installing a dimmer.
    The fix
    Use dimmer-rated LED bulbs and a compatible dimmer switch. Mismatched combinations flicker at low settings.

  6. Loose neutral connection at the panel

    PossibleNeeds a pro
    How to check
    Lights flicker throughout the house. Some circuits brighten while others dim simultaneously.
    The fix
    Call an electrician immediately. A loose service neutral is a serious fire and electrocution hazard.

  7. Aging or damaged panel

    UncommonNeeds a pro
    How to check
    Panel is Federal Pacific, Zinsco, or over 30 years old. Burning smell or buzzing from the panel.
    The fix
    Panel replacement runs $1,800 to $4,500. Many insurers require replacement of known-defective panels.

Once you know what it is

Step one

Know what it should cost

Get the range before you call, so the first number you hear is not the only number you have.

Step two

Decide repair or replace

On equipment near end of life, the repair is usually the first of several.

Step three

Check the quote

Compare against the typical range and confirm the terms before you sign.

Electrical Panel Upgrade cost guideRepair or replace calculatorEstimate repair costAnalyze a quote

What the fix costs

Tools for this decision

Other symptoms