Here's an overview of common LED dimming issues and how to fix them

Dimming LEDs may be getting easier and easier, but problems still can –– and often do –– surface when you try to run LED lamps on dimmer controls.

But why? 

Unfortunately, there's no easy answer. Diagnosing LED dimming issues isn't all that unlike diagnosing a sickness.

You start by checking vitals before looking at the symptoms of the issue.

In a dimming scenario, the vital check is pretty simple: 

Are these lamps in fact dimmable? Are they compatible with the controls they're being paired with? And are those controls still in working condition, or have they surpassed their life rating?

In medicine, the symptom of coughing does not always indicate that a patient has contracted a common cold. In fact, very few symptoms have direct, exclusive correlations to underlying cause. And it's important to note that dimming issues are similar. Different problems share similar symptoms, making it awfully difficult to diagnose the cause. (The good news is, we know a handful of cure-alls when it comes to this stuff.)

We'll go over common LED dimming problem symptoms later. Skip there now >

Then if there's a test you can perform, you use that to determine potential causes of the problem. If you show up at your doctor's office with a sore throat and a cough, she may just order a strep test for you, to definitively determine if strep throat is the cause of your symptoms.

With dimming, there are advanced tests that can be done to test out the cause behind the symptoms you're experiencing, but they can be time-consuming and often require expensive equipment. So it's typically most expedient to perform simpler field tests, read compatibility charts for the lamps you're considering, and try multiple lamps on multiple dimmer switches. (Fortunately, you're running tests on light bulbs, not human beings.)

Perhaps it's during this testing process that you encountered symptoms from the dimming attempts. Or perhaps you were previously encountering symptoms, and that's what prompted the testing.

Either way, the symptoms were probably one of the following:

7 common LED dimming issues

Throughout the history of lighting, problems tend to emerge when new technology is introduced to the market. It's not that LED is a bad technology that just isn't meant to be dimmed and can only be solved through MacGyvering efforts. There were issues dimming fluorescent lamps in the early days of that technology, too.

What we've seen over the last few years with the challenges of properly dimming LEDs are simply growing pains and, fortunately, as an industry, we appear to be past a lot of the significant problems.

Nevertheless, a common issue with LED dimmability is sudden turn on, or turn off when you try to adjust light levels with your dimmer switch. Or you may have "dead areas" as you slide your dimmer switch. Or your LED lamps may simply flicker or flash when paired with certain dimmer switches.

Here's how we'd describe some of those symptoms:

Drop out

This symptom occurs when you are trying to dim the lighting down and the light suddenly cuts out before you slide to the bottom of the switch.

Pop on

This is the inverse of "drop out" and occurs when you're sliding the dimmer switch on, to increase light levels, but your LED lamps suddenly turn on at a brighter level than you would normally except.

Dead travel

This symptom is present when your lamps don't respond to the adjustments you're making on the dimmer switch for certain sections of the dimming scale.

Ghosting

This symptom occurs when you've dimmed your lamps all the way down, but they continue to glow or produce small amounts of light.

Flickering

This symptom is understood as rapid, sporadic pulsing of your lamps when paired with dimmer switches.

Strobing

Similar to flickering, strobing occurs when your lamps rhythmically flash at a less-frequent rate than a flicker.

Flashing

This is understood to be a more sporadic, infrequent symptom of bad LED dimming, occurring when the lights randomly turn on and off when paired with a dimmer control.

LEDs won't dim? Here's how to fix the problem

Whether your LEDs are flickering or randomly dropping out, most LED dimming problems can be avoided. Remember these four things:

1. Not all LED lamps are dimmable. Make sure yours are.
2. Not all controls work with dimmable LED lamps. Read the manufacturer’s compatibility charts.
3. Some LEDs are just cheap and unproven. Buy well-tested product.
4. Always perform a mockup.

Wondering what manufacturers have proven product or where to start with your LED purchase? Download our LED Buying Guide for everything from brand recommendations to warranty advice.

Click here to learn more about LED dimming.