Why are my LED lights Flickering or Buzzing?

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LED lights are the best way to illuminate residential, industrial and commercial spaces. They offer significant energy savings compared to traditional light bulbs and can be retrofitted into a number of different fittings.

But for all their irrefutable plus points, there is one issue that comes up time and time again: visible flicker.

Often it’s nothing to do with the LED bulb at all, so let’s take a look at why it happens.


What causes LED lights to flicker?

You may never have noticed it, but all light sources flicker if they are powered from the mains.

Why?

It all comes down to electrical currents.

Electricity in the United States is delivered at a frequency of 60 Hz. This means the power supply to your home switches forwards and backwards 60 times per second.

A standard incandescent bulb will continue to emit light so long as its filament is hot. This means it will not noticeably flicker.

But in an LED, light output is directly related to the amount of current going through it at any given moment. If the current drops, the LED will stop emitting light almost instantly, resulting in flickering.

How to stop LED lights from flickering?

To fix flickering, the LED needs to be supplied with a constant current that has as little electrical noise as possible. Rather than immediately throwing away your LED bulbs, it’s highly likely one of the following solutions will overcome any irritating LED disturbances:

1. Tighten the bulb

LED bulbs can flicker if they are not fully tightened within the fitting.

Turn off the power, remove the bulb and carefully refit it securely.

2. Check for dimmer switch issues

The leading cause of LED flickering is problems with dimmer switches.

Unlike traditional lighting, not all LEDs are dimmable. Most LED bulbs you can retrofit have a driver built-in. This converts AC to DC and keeps a consistent power supply to the LED.

If you try and apply dimming before the driver, it will try to compensate for the loss of power, causing flickering.

But it’s worth noting that even a dimmable LED can flicker. This typically occurs because the dimmer switch is an older 'leading-edge' type, designed for a higher voltage range than is required for an LED.

Some manufacturers will recommend specific models of dimmers for their LED bulbs, where they’ve carried out the testing for you. If a recommendation is not available, try switching to a 'trailing edge' dimmer.

3. Check the circuit power draw

If you are retrofitting LEDs, check for other high-powered devices on the lighting circuit.

Extractor fans and ceiling fans are the most common examples. When you turn them on the voltage in the circuit suddenly increases, causing the drivers in the LED bulbs to overcompensate.

4. Are your LED drivers correct?

For most retrofit bulbs — like GU10, B22, B15, E27, E14 compatible bulbs — the drivers are built-in. This makes installation easier but limits options for dimming or non-standard installations.

Some LEDs need external drivers, such as MR16 (GU5.3), MR11 (GU4), Panels and Downlights. This makes them much more flexible, but pairing lights and drivers correctly can be difficult.

How to pair LEDs and drivers

Start by looking at the specification for the LED. The manufacturer will tell you what type of driver is required from the list below:

  • Constant Current LED Driver: This ensures that the current supplied to the LED light is constant. To prevent flicker, check the specification sheet for the driver and ensure that the voltage range is supported.
  • Constant Voltage LED Driver: This ensures that the voltage supplied to the LED is constant. Once again, check the specification sheet and check what power the voltage needs to be delivered to the driver. This should eliminate flicker.
  • AC LED Drivers: This is a specialist driver for AC LEDs and it is most commonly used for MR16 LED replacement bulbs. It takes AC power and outputs a constant DC power. As always, check the specification sheet to see supported ranges, otherwise, flicker or failure can occur.

You should also make sure to check the maximum supported wattage. For example, if your driver supports a maximum of 96 W, be sure your total LED lighting load is below this.

5. Poor quality components

If you've followed all the troubleshooting steps above, the issue might be linked to the LED bulbs you've used.

When an LED bulb fails, either due to old age or manufacturing defects, it fails gradually. This can lead to reduced lighting performance, changes in color and flickering.

LED bulbs are complex pieces of technology, so it makes sense to invest in the highest quality products from LED manufacturers with a proven record.

6. Wiring issues

If you've made it this far and you’re still wondering how to fix flickering LED lights, there could be serious electrical problems elsewhere.

If you are a qualified electrician, completing a thorough survey could reveal issues. If you’re not, it's time to speak to a specialist.

Summary and next steps

When combined with an inappropriate driver, some LED bulbs can flicker noticeably. The same flicker won’t be seen with a traditional bulb due to inherent differences in the way the two types of bulb work.

More often that not, flickering is not caused by a fault or failure with your LED bulb.

Our top tips for avoiding flicker in your LED installation are:

  • Install the LED bulb correctly, as per the manufacturer's instructions
  • Pair the right LED bulb with the right driver, reviewing the specifications for both carefully
  • Don't mix high power devices or traditional bulbs on the same circuit as LED bulbs
  • Always choose LED drivers and bulbs from a reputable manufacturer

For more tips on managing LED bulbs, visit our blog or reach out to us — we’re always happy to help.

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