Why Are My Lights Flickering?

Short answer: one flickering light is usually the globe, the dimmer or the LED driver, and it's a cheap fix. Lights that flicker across a room or the whole house, or flicker with buzzing, warmth or a burning smell, point to a loose connection. That one is a same-day call to an electrician.

Start with the globe

It sounds too simple, but a loose globe is the most common cause of a single flickering light. With the light switched off and the globe cool, check it's screwed or twisted in firmly. If it still flickers, swap in a globe you know works. If the new one is steady, the old globe was failing.

Old fluorescent tubes flicker as they die, and so do cheap LED globes once their internal electronics start to fail. If it's a tube or an LED that's a few years old, replace it before you look any further.

LEDs on the wrong dimmer

This is the big one in houses that swapped halogens for LEDs. Most older dimmers were designed for halogen globes, which draw ten times the power. An LED's load is too small for them to control smoothly, so the light flickers, hums, or won't dim all the way down.

The fix is an LED-rated dimmer that matches your globes, and sometimes different globes. A mix of brands on one dimmer can flicker too, because each LED responds differently. If you've just had LEDs put in and the flicker started then, this is almost certainly the cause.

A failing LED driver

Most LED downlights have a small driver above the ceiling that turns mains power into what the LED needs. When a driver starts to fail, the light flickers, strobes or cuts out after warming up. One downlight playing up while the rest are fine is usually its driver, and replacing it is a quick job.

Big appliances starting up

A split system, a pool pump or an old fridge draws a surge of current as its motor starts. On the same circuit, or in an older house with a small main cable, that surge dips the voltage for an instant and the lights dim. A short dim now and then is normal.

If the lights flicker hard every time the air conditioner kicks in, or lights on a different circuit dim too, the circuit may be overloaded or a connection may be loose. In plenty of older Newcastle homes the split system was added onto a circuit that was already busy. A dedicated circuit for it fixes the flicker and takes load off the rest of the house.

Loose connections: the one that matters

Every switch, light fitting and circuit breaker has screw terminals, and over years of heating and cooling they can work loose. A loose connection arcs, and arcing makes lights flicker. It also makes heat, which is how electrical fires start.

Treat flickering as urgent if you notice any of these:

• buzzing or crackling from a switch, a light or the switchboard
• a switch plate or power point that feels warm
• a burning or hot-plastic smell
• scorch marks or discolouring around a switch or fitting
• flickering that moves around the house rather than staying on one light

If you notice any of them, turn that circuit off at the switchboard and ring us. Don't wait for business hours.

When the whole house flickers

If every light in the house flickers at once, the problem is upstream of your circuits. It could be the main connection in the switchboard, the service line from the street, or the network itself. Check with a neighbour first. If their lights are doing it too, report it to Ausgrid on 13 13 88. If it's only your house, it's a same-day job for an electrician, because a loose main connection affects everything downstream.

An old switchboard can be part of the story too. Our switchboard upgrades page covers the signs a board is past it, and if your lights flicker every time the safety switch is close to tripping, our post on why a safety switch keeps tripping walks through finding the fault.

Flickering outdoor lights

Outside lights have it harder. Sensor lights flicker when the sensor is failing or a cheap LED globe can't cope with it, and a fitting that flickers after rain usually has water inside. Close to the coast and the lake, salt air corrodes terminals and globe holders faster than it does inland. A weather-rated fitting with stainless fixings lasts years longer, and if the light shares a circuit with your safety switch, fixing the water often stops the tripping too.

What it costs to fix

Most flickering lights are a small job. A new LED-rated dimmer or a replacement driver usually takes under an hour, and a loose connection is often found and fixed in the same visit. The electrician cost guide has typical prices, and quotes are free.