Why are my lights flickering?
By Azzeddine Kebbi, NAPIT-registered electrician and director of Kebbi Electrical Services · Updated 10 November 2026
If one light flickers, it is usually the bulb, a dimmer that does not suit LEDs, or a loose connection in the fitting. If lights flicker all over the house, the cause is more likely the supply or a loose connection at the main board. Here is how to narrow it down.
First, stay safe
- If you smell burning, hear crackling or a switch or fitting is hot, switch off at the consumer unit and call an electrician.
- Do not take fittings apart yourself.
Common causes
Loose or failing bulb
Switch off, let it cool, then check it is screwed or pushed in firmly. Try a new bulb.
Dimmer and LED mismatch
Older dimmers often make LED bulbs flicker. Dimmable LEDs and a matching dimmer usually fix it.
Loose connection
A loose terminal in a switch or fitting can flicker and get hot. This needs fixing.
Big appliances starting
A brief dip when a shower, oven or heater switches on can be normal. Frequent or strong dips are worth checking.
One light or the whole house?
- One light: start with the bulb, then the dimmer. If that does not fix it, have the fitting and switch checked.
- One room or circuit: could be a loose connection on that circuit. Book an electrician.
- The whole house: if neighbours are affected too, call 105, the free power cut line. In Bristol this goes to National Grid Electricity Distribution, which runs the local network. If it is just your home, have the main connections checked.
Common questions
Are flickering lights dangerous?
Sometimes. A cheap bulb or a dimmer mismatch is not dangerous. A loose connection can overheat, so flickering with heat, buzzing or a burning smell needs an electrician straight away.
Why do my LED lights flicker?
Usually because the dimmer is not designed for LEDs, the bulbs are not dimmable, or the LED driver is failing.
Why do my lights flicker when the shower or oven turns on?
High-power appliances can cause a short voltage dip. A slight dip can be normal, but strong or frequent flicker should be checked.
Why are all the lights in my house flickering?
It may be a supply issue or a loose main connection. If neighbours have it too, call 105. If not, get an electrician to check your consumer unit and connections.
Lights still flickering?
We find the cause, fix loose connections and replace faulty switches, dimmers and fittings. See our electrical installations and repairs.