Why Are My Lights Flickering?

A light that flickers is irritating, and it's natural to worry about what it means. The good news is that many causes are simple: the lamp, the dimmer or a big appliance switching on. A smaller number point to a loose connection in the wiring, which needs attention. This guide goes through the causes from the most common and explains which checks are safe to make yourself.

Start with what is flickering

Ask yourself a few questions. Is it one light, one room or the whole house? Does it happen all the time, or only when something else is switched on? Are the lamps LEDs, and is the light on a dimmer? Has anything changed recently, such as new lamps or a new switch? The answers point towards the likely cause.

LED lamps and dimmer switches

This is the most common cause in modern homes. Many older dimmer switches were designed for traditional filament bulbs and don't control LEDs smoothly, producing flicker, buzzing or lamps that won't fully switch off. Some LED lamps aren't dimmable at all. Cheap LED lamps and drivers can also flicker as they age. A safe first step is to try a good-quality dimmable LED lamp from a known brand. If the flicker continues, the dimmer probably needs replacing with an LED-compatible type, which is a job for an electrician.

A loose lamp

A lamp that isn't seated firmly in its holder can flicker as it makes and breaks contact. With the light switched off and the lamp cool, check it is pushed or screwed fully home. If the holder looks scorched, cracked or discoloured, don't use the light; get it replaced.

Heavy appliances starting up

A brief dim as a kettle, washing machine, heater, electric shower or power tool starts is common and usually harmless. Large loads draw a burst of current that slightly lowers the voltage. A noticeable or prolonged dip, or one that has got worse recently, can mean a weak connection somewhere on the circuit or at the board and is worth getting checked.

A loose connection in the wiring

Connections in switches, ceiling roses, junction boxes and the consumer unit can work loose over time. A loose connection causes intermittent flicker that may not follow any pattern, and it generates heat. Warning signs include buzzing or crackling from a switch or fitting, a switch plate that feels warm, discoloured plastic or a smell of burning. If you notice any of these, stop using the light, switch the circuit off at the consumer unit if it is safe to do so, and call an electrician. Do not open fittings to investigate.

A problem with the supply

If lights flicker throughout the house, and especially if neighbours notice the same, the cause may be on the electricity network outside your property. Call 105, the free national number that puts you through to your local network operator, who is responsible for the supply up to your meter.

Safe checks, in summary

Try a different, good-quality lamp. Check the lamp is seated properly with the light off and cool. Notice whether flicker follows a particular appliance. Ask neighbours if they see it too. That's where your checks should stop. Anything involving switches, fittings or the board is work for an electrician.

When to call us

Call if flicker continues after a lamp change, affects several lights, comes with buzzing, heat or smell, or happens alongside tripping. Our fault finding service tests the circuit to locate the cause. If you are planning new lights anyway, our lighting installation page covers dimmers and fittings chosen to work together.

Outdoor and fluorescent lights

Fluorescent tubes in garages and workshops often flicker as they reach the end of their life or when the starter fails, especially in cold weather. Replacing the tube or the whole fitting with an LED batten is a common fix. Outdoor lights that flicker after rain may have water in the fitting; switch them off at the consumer unit and have them checked rather than leaving them on. Security lights with sensors can also flicker if the sensor is faulty or poorly positioned.

Smart bulbs and switches

Smart lamps and smart switches sometimes flicker when used together, or when a smart switch has no neutral connection to draw a small standby current from. Check the manufacturer's compatibility list before mixing products.