There are many potential causes of flickering lights.
Sometimes flickering is caused by low quality LED lights. In other cases, we encounter strobing or blinking related to transformers or the dimming of LEDs. A common complaint is LED downlight flickering.
Finally, there are some lesser-known flickering phenomena. These include high frequency flicker and intermittent flicker from the electricity grid.
In this article, I'll discuss six key issues, and some solutions to each.
Strobing lights are annoying, and often a little tricky to solve.
1) Low Quality LED Lights That Flicker
Even when no dimmer switch is present, some LED lights can still flicker. This is often the case with cheap or low quality LED lights. They may work fine out of the box but then develop a flicker before prematurely failing. We often hear from customers who purchased LED lights on eBay, Kogan, Amazon, or at Bunnings, only to have them die within a year.
Test & Solutions:
- If you suspect an LED light has gone 'on the blink' start by testing it out in another socket or fitting. If the flickering stops in a new fitting, you may have another issue (read on). If the flickering persists - you may have a dud light bulb.
- As a general rule, buy quality lights from trusted brands, such as Philips & Osram.
- Buy from sellers who back their products with believable warranties. As an example, we offer a minimum 2 year warranty on all the LED lights that we sell. Most of our lighting products carry a 3 or 5 year warranty - and are expected to last much longer than that.
Buying quality brands from a reputable retailer is often the quickest way to eliminate flickering LED lights.
2) Incompatible or Under-Loaded LED Dimmers
After upgrading to LED lights you may experience flickering or flashing from an old dimmer switch. An underloaded dimmer is most often the cause of this. Old fashioned dimmers were not designed to control loads below around 20W. As such, they can sometimes struggle to dim a small number of low power LED lights.
Our Recommended Approach:
Start by purchasing products that have market-proven wide compatibility, such as our range of dimmable LED lights. Just because other lights have flickered, it does not mean that all LEDs will flicker with your dimmer.
Order at least enough lights for a complete room or light switch. So if you have 6 lights attached to one dimmer, that's a good minimum number to order. This way, you can test them out with your existing dimmers, before committing to a complete upgrade.
Now, if you have done the above and flickering is detected you can do some further testing. Add one of your old higher power light bulbs back to the affected circuit. If the flickering stops, you can either:
- leave the lights as-is with the slightly increased load,
- ask an electrician to remove (wire out) the dimmer, or
- upgrade the dimmer.
If necessary, upgrade to an LED optimised dimmer such as our Diginet dimmer range. Alternatively, you may be able to add a 'load correction device' to existing Clipsal dimmers or a 'load bypass device' for the Diginet range.
Lighting dimmers typically sit behind the switch plate as pictured here. As such, they are a quick job for an electrician to upgrade or replace.
3) LED Downlight Flickering (12V Lighting Flicker - Transformer or Connection)
Whether or not a dimmer is involved, low voltage lights such as 12V MR16's can sometimes flicker. Apart from the dimmer issue already discussed above, this can also be due to:
- Incompatible transformers. Most old transformers have a stated output range of 20W to 50W. However, our Philips MR16 LED 7W bulbs have some smarts built into them, so they still work with old transformers, even at this lower load. Other brands, and in very rare cases the Philips bulbs, may require a 12V LED transformer to work well.
- Loose electrical connections. This can potentially happen with any light bulb or fitting. But in my experience, it's most common with 12V MR16 / GU5.3, MR11 or G4 low voltage light bulbs. The low voltage (12V) connectors on these lights often degrade over time.
- First up, test the affected light bulb in another fitting. If the flickering stops, it's quite likely just a loose connection. If the flickering persists (and a dimmer has been ruled out as the cause) then a new transformer may be required.
- An alternative solution is to do away with 12V MR16 lighting altogether and upgrade to a mains voltage LED downlight. These are the fully integrated units that come pre-wired with a standard 2-pin power plug.
- With the lighting circuit turned off, visually inspect the light socket or wiring for any issues. If it's a mains voltage light, you may need to ask an electrician to repair or replace. If it's a 12V light fitting, the fix can be as simple as replacing the low voltage connector, pictured below.
Sometimes degraded or damaged wiring such as MR16 connectors can cause flickering.
4) Fluorescent Light Flickering / Strobing / Blinking & Buzzing
Another common form of flickering is the fluorescent tube, in all its forms. Fluros can flicker when they are reaching the end of their life, or if the ballast is faulty.
In this case, LED tube lighting actually presents a solution, rather than being part of the problem! Often, upgrading to LED will both get rid of the flicker and massively reduce your energy usage.
If your fluorescent light fittings have brittle connectors (AKA 'tombstones') it could be time to upgrade the whole fitting. In this case, see our range of LED panel lights and LED batten lights. These lights are fully integrated - which means they no longer contain a separate 'tube' inside them.
We've all seen flickering fluro tubes... And don't get me started on that mismatched colour temperature!
5) Intermittent Flickering From Power Quality & Grid Disturbances
Energy utilities control off-peak loads by sending a 'ripple' through the electricity grid. Often, this electrical signal can show up in the form of flickering lights or noisy fans. It's particularly annoying because it occurs late at night.
Other disturbances on the grid can be due to nearby electrical loads. Like when your neighbour cranks up their welder or high power grinder - your lights may flicker.
In both cases above, we return to point one: buying quality products is generally the best antidote to these problems. I have all kinds of Philips LED lights throughout my house and have never encountered this kind of intermittent flicker. But we certainly have heard of it from many of our customers using other products.
Off-Peak hot water systems causing your lights to flicker? Well, they can, in a roundabout way.
6) High Frequency Light Flicker
High frequency strobing is hard to detect with your eyes. This issue relates to the fact we have a 50Hz electricity supply. In this system, electrical current alternates or cycles 50 times per second. Well designed LED lights effectively 'smooth out' this constant back and forth of the current flow. Cheap and nasty LEDs cycle on and off completely, 50 times per second.
We know this is bad because old-style fluorescent tubes can suffer from the same problem (link). High frequency flicker in offices has been linked to increased headaches and visual discomfort. This is yet another argument to upgrade from fluro to LED, in case you needed one.
We now test all the lights we sell for this type of flicker with a costly gadget (pictured above). Your phone camera can potentially provide some insight into this as well (the pulsing screen is an indicator of this flicker).
As a general rule, better quality brands (see point 1) address this issue with proper electronics design from the outset.