Why Do LED Bulbs Buzz When Dimmed?

Only a few things are more annoying than the terribly disturbing consistent buzzing sound that seems to be coming from some overhead lights.

Do you simply want to get out of that place as soon as you are able? Yea, you and me both.

But stay a moment, and let’s figure out why the lights are doing that and if it can be fixed? You’ll be glad to know they most likely can be. Ah, sweet relief with the silent bulb.

Often an incompatible dimmer switch hooked up to new LED bulbs, can cause buzzing noise to be produced due to electromagnetic interference or rapid switching from AC to DC current.

Why Do LEDs Hum?

When trying to figure out why LEDs hum, one thing you can be assured is that if an LED is humming, it is not necessarily defective.

The buzzing or humming is simply an indication that something is wrong that can be fixed. It is an LED’s cry for help.

As opposed to other LED issues where the reason is usually a cheap quality product, in the case of buzzing, even a high-quality bulb can make the sound.

One of the reasons that an LED would start to hum is when you turn on a microwave, for example, in your kitchen.

The surge in power through the circuit in the kitchen causes your LED to buzz. The LED driver is trying to regulate the voltage to continue functioning.

An easy fix is to move heavy load equipment and the LEDs to different circuits. In a well-designed space, heavy load appliances should, by default, be on independent phases to prevent surge issues.

A humming LED that is also flickering is usually a sign of loose connections and wiring around the fixtures and circuit breakers in an older home.

Once you give that a thorough check, tightening all connections, the buzzing should stop.

Perhaps you might be wondering what exactly occurs in an LED to make it go buzz.

The humming or buzzing that comes from a malfunctioning LED is not through a vibrating filament or apart.

Due to interference in the way lower current and voltage reach the bulb through the driver.

LEDs work alongside a driver that switches high voltage AC current into low voltage DC. The driver switches power by turning on and off rapidly.

This switching can also sometimes cause an audible buzzing sound.

How Dimmer Makes Buzzing Noise In LEDs?

light switch

Almost every time the reason for LEDs humming when used with a dimmer switch is when the bulb’s power supply, aka driver, is incompatible with a dimmer system.

It is actually the solid-state driver making the buzzing noise, and not the lighting emitting diode itself.

LED tech functions in binary computational on/off state. You should try to understand that an LED is more like computer technology. And just like computers, LEDs run on low-voltage DC current.

On the flip side, older dimmers worked with incandescents that need 240 Volt AC current. This discrepancy between new LEDs plugged into old dimmers, results in various issues, including buzzing from the switches.

An incompatible dimmer switch wired to a newer LED fixture or bulb will produce a humming sound as it turns on/off at irregular intervals, indicating electromagnetic interference (EMI).

A traditional dimmer evenly alters the voltage going into the circuit and to the conventional bulb, to dim it. An LED bulb cannot respond to that gradual change in voltage.

Is Buzzing Light Dangerous?

First of all, give a thorough inspection of the circuit breaker. If the buzzing is coming from there, it is most DEFINITELY a dangerous scenario.

This is because short or loose wires can cause electrical arcing and may soon result in sparks or, worse, an electrical fire.

Tighten, repair, and insulate all wiring from the mains to the circuit breaker, and keep an ear out for any more sounds.

However, it is possible that a buzz or hum can seem to come from the entire light fixture, and you cannot pinpoint what’s the cause.

It is likely that the bulb or the wiring is loose and causing the humming, and there are some simple fixes.

You should clean the electrical contacts, screw in the bulb tighter, and tighten any wiring coming short.

If the humming is not related to the actual EMI, then these external factors need to be checked out in case the buzzing is an indicator of another problem.

It could also turn out the buzzing only seems to be coming from the bulb, but is actually coming from the dimmer switch, where again, loose wiring needs to be checked.

Apart from a short circuit in the breaker, buzzing from an LED itself is not dangerous but definitely disturbing. In fact, with constant exposure to such low-frequency sound, one can develop stress, causing you to make mistakes.

If such buzzing occurs at a workplace like a factory or a garage, one can injure themselves due to the distraction and stress caused by a low constant buzzing.

What Can I Do To Get Rid Of Humming?

Surprisingly, your LEDs may still hum even if you have purchased compatible dimmer and LEDs. There’s a very unfortunate semantic explanation for that.

Manufacturers who have been contacted for this issue say that a bulb and dimmer are considered compatible according to them, as long as you cannot hear it more than 2 feet away!

Talk about a loophole.

There is a solution, though.

One surefire dimmer spec that almost always fixes a buzzing issue is called an electronic low voltage, or ELV dimmer (Amazon). They are not cheap.

But they are reverse-phase dimmers that regulate the power for an easy on and follow with a full shut off.

Another dimmer type that works well is digital volt dimming systems (Amazon), or zero-to-10V step dimmer. Often however, regular, fully compatible, dimming switches do eliminate the humming problem.

Another exciting alternative on the market is a smart LED bulbs like Philips Hue (Amazon), where no need for an old dimmer or aged wiring remains, and is a complete solution of dimmable light in itself, among other features.

Apart from that, do the necessary tightening and cleaning of connections and wires with the help of an electrician.

Final Words

A lot of science from incandescents does not apply to the working of an LED bulb.

Since the two don’t function in the same way, it is essential to know what is causing problems in the LEDs, which are everywhere now.

Stay updated with my blog, and you’ll increase your understanding of LEDs every time!

Have you installed new LEDs with old dimmers and heard buzzing?

Are they compatible? Did you check what the source of the noise is?