Short answer: Flickering lights are usually caused by an LED globe that doesn’t suit its dimmer, a failing globe or driver, or a loose connection in the fitting or switch. If just one light flickers, it’s usually the fitting. If lights flicker throughout the house, especially when big appliances start, or if you notice dimming, buzzing, heat or tingles, it can point to a wiring or supply problem that needs an electrician or Ausgrid.
A light that flickers now and then is easy to ignore. Most of the time the cause is harmless, but occasionally flickering is the first sign of a loose connection that’s heating up. Here’s how to work out which is which.
Start by asking: one light, one room, or the whole house?
One light flickers
This is the most common situation and usually the least serious. Likely causes:
- LED and dimmer mismatch. Many older dimmers were designed for halogen or incandescent globes. LEDs draw much less power, and on an incompatible dimmer they can flicker, buzz, or never fully switch off.
- A failing globe or driver. LED downlights have a driver (a small power supply) that can fail with age or heat. Cheap drivers often fail first.
- A loose globe in a batten holder or lamp.
- A loose connection at the fitting or switch.
Try a known-good globe first. If that fixes it, you’re done. If the light is dimmable, check the globe is rated as dimmable and compatible with the dimmer.
Several lights on one circuit flicker
If all the lights in one area flicker together, the problem is likely on that circuit: a loose connection at a switch, junction or the switchboard, or a dimmer feeding several lights that’s struggling. This needs an electrician.
Lights flicker throughout the house
Whole-house flicker can come from:
- big appliances starting, such as air conditioners, pool pumps or older fridges, causing a brief voltage dip
- a loose connection at the switchboard or main switch
- a supply problem, such as a deteriorating neutral connection or a network fault
A brief dip when the air conditioner kicks in can be normal. Constant flicker, lights that brighten and dim, or flickering with other symptoms isn’t.
Warning signs that make it urgent
Call an electrician promptly, or Ausgrid if it’s a supply issue, if flickering comes with:
- a burning or fishy smell, or a switch or power point that’s warm to touch
- buzzing or crackling from a switch, fitting or the switchboard
- lights that go noticeably brighter as well as dimmer
- appliances behaving oddly, or electronics failing
- a tingle or shock from a tap, appliance or metal fixture
Ausgrid treats shocks and tingles as electrical emergencies. Call 000 if anyone’s in danger, and report it to Ausgrid on 13 13 88.
Common causes in Inner West homes
Older homes in suburbs like Stanmore, Lilyfield and Forest Lodge often have wiring that’s been added to in stages over many decades. That can mean:
- old switches and connections that have loosened over time
- mixed old and new cabling joined in the ceiling
- dimmers installed years ago for halogen globes, now running LEDs
- lighting circuits without an earth
None of these automatically means danger, but they make flickering more likely and are worth having checked. If your home still has old wiring, flickering is a good prompt for an inspection.
Fixing dimmer flicker properly
The fix is usually one of:
- Replace the dimmer with an LED-compatible model. Check the LED maker’s list of tested dimmers.
- Use LED globes or downlights designed for dimming. Non-dimmable LEDs on a dimmer will misbehave.
- Check the minimum load. Some dimmers need a minimum load to work properly. A single low-wattage LED may fall below it.
- Match the dimming type. Trailing-edge dimmers generally suit LEDs better than older leading-edge types, but always check the maker’s recommendations.
Our LED downlight buying guide covers dimmer compatibility in more detail.
What not to do
- Don’t open switches, fittings or the switchboard to tighten connections yourself. In NSW, any electrical wiring work needs a licence, according to NSW Government guidance.
- Don’t ignore flicker that comes with heat or smell. Loose connections generate heat, and electrical faults and appliances cause around 40% of NSW house fires each year, according to the NSW Government.
Lights playing up? We sort out flickering lights, dimmers and loose connections across the Inner West, including Dulwich Hill, Leichhardt and Marrickville. See our fault finding service, or call 0421 772 661.
Frequently asked questions
Why do my LED lights flicker when dimmed?
Usually because the dimmer isn’t compatible with the LEDs, the LEDs aren’t dimmable, or the load is below the dimmer’s minimum. An LED-compatible dimmer usually fixes it.
Is it dangerous if my lights flicker?
A single flickering globe usually isn’t. Flicker with heat, buzzing, a burning smell, lights getting brighter, or tingles from taps can be dangerous and should be checked promptly.
Why do my lights dim when the air conditioner starts?
A large motor starting causes a brief voltage dip. A short, slight dip can be normal. Severe or constant dimming may point to a loose connection or supply issue that needs checking.
Can a bad switch cause flickering?
Yes. Worn or loose switches can cause intermittent contact and flicker. Replacing a switch is a job for a licensed electrician.