Why do my lights flicker, and how do I fix them?

LED Light Flickering


There is nothing more frustrating than the disappointment of purchasing new lights with the goal of saving money and saving the planet, to find they flicker, pulse, shimmer, strobe, and generally perform badly. Isn't LED lighting supposed to be the electrical revolution that saves uberwatts of electricity, while improving the brightness and quality of our light?  It is and it will, as long as you make informed decisions when you purchase.

Flickering without a dimmer

If you have just purchased some LED fittings and had them installed on a circuit that has a simple switch, and not a dimmer, and you see flickering or strobing; then unfortunately the news isn't good.  It is highly likely that the fittings you have purchased are not good quality, have not been manufactured or tested for Australia, or less likely, your wiring needs to be looked at by a professional. 

There is no good reason for a new LED light on a simple wall switch to flicker or pulse.  Although the LCD (Load Correction Device) fix detailed below may work, in all likelihood you will need to replace the lights. 

Although we at moodLED love the effect dimmers can have on your lighting (read: Dimming for Dummies, 8 Reasons to Dim, Mood lighting through dimming lights), we understand some lighting circuits don’t need to be on a dimmer. The best way to ensure a light doesn't flicker when on a switch, is to use one that performs brilliantly without flickering on a dimmer.  See our range of flicker free lights here: moodled.com.au/collections/all

Flickering when dimming

LED lights that flicker while being dimmed down are the main source of frustration for people. Previously, with incandescent lights, dimming could be achieved gracefully in most scenarios.  Then trying to do the right thing, you upgrade to the new LED technology, and introduce flickering and shimmering.  And the worst part about it, you even purposely selected the light that said it was dimmable on the side of the box. 

LED lights will always highlight in their specs if they are dimmable or not dimmable.  If they don't mention it at all then you can bet they are non-dimmable. If an LED is non-dimmable, then connecting it to a dimmer will likely not show any difference in brightness as you dim it, and eventually turning off completely as you dim further. 

The biggest problem is that LED's labelled dimmable, at minimum have been electrically designed to dim their brightness when matched with a dimmer. "Simple" I hear you say, problem solved.  However, more than 80% of 'dimmable' LED's will flicker, strobe, pulse, or shimmer depending on these variables. 

  • Type of dimmer (see blog article on type of dimmers)
  • Quantity of lights on the circuit
  • How your house is wired
  • What state you live in (see section on NSW and SE QLD)
  • Mixed Light types/models on a circuit
  • Too many dimmers on a single switch plate

Type of Dimmer

In the world of dimmers there are 2 main varieties, Leading Edge and Trailing Edge.  LED lights will usually be calibrated to work with one not the other.  If you have existing dimmers that are Leading Edge, and your light wants Trailing Edge, you will most likely experience one or more of these symptoms; poor dimming, flickering, shimmering, or pulsing.
Unfortunately, to fix this issue, you will need to replace either the lights or the dimmers.  If you don't know what type the dimmers are, you may be better off replacing them, and ensuring your lights will match.  The hard part is that most LED sales information will not specify which style of dimmer it suits, and dimming test data will usually not be available.  This is the reason moodLED was born.  We have tested hundreds of models of lights to find the 'best of breed' models for each type of dimmer.  We then publish our test results right on the website.  www.moodled.com.au
Some of the latest dimmer technology can dramatically improve light/dimmer compatibility.  New technology is reducing the chance of negative results by designing the circuitry specifically for LED lights, and not older types.  Diginet has made arguably the best LED specific dimmer on the market, achieving the most compatibility and the best results.  See it here https://moodled.com.au/products/diginet-mmdm-rt-ledsmart-rotary-dimmer.

Quantity of lights on a circuit

One reason LED's can dim poorly is if there are too many on the circuit.  Although a 400W dimmer in theory can run up to around 40 LED downlights, in practice, there are other variables in the design of a light fitting that can impact on this.  In our experience, if you want to run more than 6 lights on a circuit, you should test first.    


What state you live in

This might seem like a strange criteria for your LED dimming performance, but even a well designed LED light that is perfectly compatible with the dimmer it's attached to, can rhythmically pulse at certain times in an evening.  This is caused by energy supply utilities broadcasting ripple signals on the mains cabling for off-peak electric devices such as hot water systems.  It most comonly happens in SE QLD and NSW.
These high-frequency signals are received by all consumers connected to the grid in that area irrespective of whether they have tariff changing equipment installed in their switchboard or not.  The result can be regular periods of LED downlights flickering of 10 – 15 mins duration spread over an hour or more. This typically occurs in the late evening or afternoon and is normally only noticeable on lights controlled by dimmers. The signal may not be received correctly the first time around which is why it is repeated.  Most often the flickering of the lights is only noticeable when the lights are dimmed, the more dimmed the lights are the more noticeable the flickering is. 
This has always occurred, however, prior to LED lighting, the tungsten and halogen lamps held sufficient thermal inertia such that the flickering was accommodated by those light sources without materialising to occupants.  There is no cheap or easy fix and discussions with supply authorities and Australian manufacturers continues to try and solve the LED Downlights flickering.
Once again this doesn't manifest in all lights.  Depending on the resistive and filtering electronics in the driver, some will and some won’t.  LED manufacturers are not designing the electronics to be impervious to this ripple, as it is a relatively local phenomenon.  It also doesn't seem to be about the cost of the light.  We have $25 downlights that don’t flicker due to ripple, and I've tested $100+ lights from major manufacturers that do.
Once again, all the LED fittings at moodLED have been tested in SE QLD and do not suffer from the pulsing effect caused by this ripple in the mains power.



Many of you are probably asking the question "But if the lights I buy conform to all Australian standards, why would I have a problem"?  And it's a good question.  However all of the Australian standards required to sell an LED light in Australia revolve around electrical design, electrical safety, heat dissipation, etc.  They are not performance standards but safety standards.  Unfortunately, there are no official performance standards that will assist you with grading dimming performance.  All you will have is the results of private tests performed by very few manufacturers/importers who actually care about dimming performance.  Therefore it's a good idea before purchasing a whole house worth of lighting, to do some testing of your own.

How do I fix it?

So now that we've established why and what, how can we go about fixing the flickering we have in our homes now?  There are 4 main ways to attack the problem, with a significant difference in the impact to your wallet.  The fixes below are in order of increasing expense.
  1. Add an LCD (Load correction device) - Because an LED light is a non-resistive load, some of the problems above can manifest, particularly when there are only 1 or 2 lights on a circuit.  An LCD won’t fix all scenarios, but it's a good place to start as it's a $20 part and a quick visit from your electrician.  Essentially it is a small capacitor/resistor that gets wired into the circuit.
  2. Change the dimmer - If you have invested in LED lights but used your old dimmers, upgrading to the latest dimmer technology may solve the problem.  Again, one of the best in-wall dimmers available can be found here https://moodled.com.au/products/diginet-mmdm-rt-ledsmart-rotary-dimmer
  3. Replace your LED lights - There may be some cases where you have inadvertently purchased a dud light fitting, that just wasn't designed to dim properly.  You may have no choice in this scenario but to replace the fittings with new.  Make sure to buy only fittings that have been thoroughly tested, with published test results. The obvious place to find quality dimmable lighting is here https://moodled.com.au/collections/all.
  4. Replace with Smart Bulbs - Another method is to change all your light fittings to smart lights.  These will have dimming circuitry built in that is designed in conjunction with the light itself to produce good dimming results. Obviously, there will be a raft of other high-tech functionality built in as well.  Find a range here https://moodled.com.au/collections/smart-light-bulb.

Although this article is focused on what can go wrong when you update to LED lights, the majority of people who do have no such issues, and enjoy great savings on their energy bill, and improved lighting in their homes.  Well, moodLED customers certainly do.




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