This article has been updated with the latest LED dimming information and technology. It was originally published in 2017.
It wasn't that long ago we were answering the question: can LED lights be dimmed? The answer is yes, but years later problems can still surface when you try to run LED lamps or fixtures on dimmer controls.
Why are there still issues, even when lamps and fixtures are more reliable and dimmers more tolerant?
Unfortunately, there's no easy answer. Diagnosing LED dimming issues is somewhat similar to diagnosing a sickness.
You start by checking vitals before looking at the symptoms of the issue.
In a dimming scenario, start with this checklist:
- Are these lamps in fact dimmable?
- Are the drivers in my fixtures 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 a common cold. 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.)
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
To simplify the process, start with field tests, compatibility charts for the lamps or fixtures you're considering, and try multiple lamps on multiple dimmer switches. (Fortunately, you're running tests on light bulbs, not human beings.)
One interesting note is that dimming is always related to the driver, which is a separate component in most fixtures and retrofit kits. Similar to lamps, a compatibility check at the beginning is critical to ensure success.
Maybe you encountered these symptoms during the testing process. Or maybe 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. There were issues dimming fluorescent lamps in the early days of that technology, just like LED lamps.
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
A common issue with LED
Here's how we'd describe some of those symptoms:
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.
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.
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.
This symptom occurs when you've dimmed your lamps all the way down, but they continue to glow or produce small amounts of light.
This symptom is understood as rapid, sporadic pulsing of your lamps when paired with dimmer switches.
Similar to flickering, strobing occurs when your lamps rhythmically flash at a less-frequent rate than a flicker.
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.
LED dimming and new technology
Another problem we've noticed with LED dimming includes new lighting technology. This might sound backwards but using the latest and brightest lighting lamps and fixtures may not work for every setting.
For example, restaurants and hotels may want to set a certain ambiance using LED lights on a dimmer. New LED fixtures can be so bright and efficient, you have to take the lights down very low on the dimmer in order to get them to the right level. That's often when we notice problems.
It takes a very specific fixture to be able to dim to your desire.
Not sure which fixture or lamp is best for your setting? Ask a lighting expert.
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:
- Not all LED lamps are dimmable. Make sure yours are.
- Not all controls work with dimmable LED lamps. Read the manufacturer’s compatibility charts.
- Some LEDs are just cheap and unproven. Buy well-tested product.
- Always perform a mockup.
Wondering what manufacturers have proven
LED dimming and Title 24
If you're in California, you have a different set of regulations to consider for LED dimming. We dove headfirst into Title 24 several years ago. You can look through our resources and let us know if you have any questions.