LED lights are suitable for a wide range of applications, both in commercial or residential settings. LED bulbs can also be retrofitted into a range of traditional fittings in moments, replacing existing incandescent, fluorescent, and halogen bulbs.
However, not all LEDs are dimmable.
This means, in certain situations, you’ll need to assess the exact bulb you’re buying to make sure it fits your needs — especially if you’re replacing other bulb types with LEDs, and want them to be able to dim.
In this guide, we’ll explain how you can quickly determine whether an LED light bulb is dimmable, and which LED dimmer is right for you.
Why choose dimmable LED lights?
It’s increasingly common for rooms to serve multiple purposes in the home. For example, a kitchen could be somewhere to eat in the morning and at night, but be an office space during the day.
Dimmable LED lighting gives you the flexibility to optimize your lighting to match your activity. For instance, You might want a bright and energetic light for productive working in the day and cozy dimmed light for a relaxing meal in evening.
The same applies in commercial and industrial environments. Adding dimmable lighting offers flexibility, allowing staff to adjust the lighting to their preferences and requirements.
Is your LED light dimmable?
The short answer: it depends. Not all LED lights are dimmable, so you need to check two things to be sure.
First, check whether the LED specifically states that it is dimmable in the product description or technical specification. If you decide to use a non-dimmable LED on a dimmer, you'll get flickering and damage the bulb, dramatically reducing the lifespan of the LED.
You might also see symbols on the package, much like the ones below. Sadly, there is no standard for these symbols, so they can vary between manufacturers.
Secondly, check if your dimmer is LED compatible. If you are replacing incandescent bulbs with LED bulbs, you likely have a leading edge dimmer. These are designed to work with a high wattage, so they don't work for low wattage LED bulbs.
You'll need to replace this dimmer with a trailing edge dimmer, which is designed to work with low voltage LED lights.
Why are not all LED lights dimmable?
Whether an LED light is dimmable or not depends on the driver the light uses.
All LED bulbs include drivers that convert the electricity into a low-voltage current that is needed for the LED to work.
It also moderates the supply to prevent voltage and current fluctuations, which could cause flickering or shorten the lifespan of the LED bulb.
This LED driver determines whether an LED bulb is dimmable or not.
- A non-dimmable LED driver knows only two states: ON or OFF. If you reduce or increase the current to the bulb, it will try to moderate the current and eventually fail.
- A dimmable LED driver expects a drop in current and is therefore able to support different levels of currents. More specifically, a dimmable LED driver will compensate for the loss of current by dimming the LED with analog dimming or by pulse width modulation (PWM).
Although all dimmable drivers should be able to support different currents, low quality LED bulbs will likely have low quality drivers. Therefore, if you buy a low quality LED, you should prepare yourself for suboptimal dimming results.
How are LED lights dimmed?
To understand how LED lights dim, it’s worth comparing LEDs to incandescent bulbs for a moment.
Incandescent bulbs produce light by making a wire filament so hot that it glows. To make it dim, simply provide less voltage and the wire won't get as hot, resulting in less light. This can be described as analog, as light can be controlled on a range from 0% to 100%.
LED bulbs, however, produce light from a diode, which only has two states. It is either ON and producing light, or OFF and completely dark.
This means we need a different way to produce a dimming effect in LED bulbs. For which there are two main methods: Pulse Width Modulation (PWM) and analog dimming.
Pulse Width Modulation (PWM)
With PWM, if you wanted to dim an LED to 70% brightness, you keep the LED on for 70% of the time and off for the remaining 30%. On average, you have 70% light, so mission accomplished, right?
But why don't we notice the bulb turning on and off?
PWMs exploit a problem with our vision. The light is flickering, but the human eye can only see at a frequency of around 80Hz. In the background, our brain automatically fills in the gaps to make our vision feel smooth. It does this by averaging the difference, meaning the light appears dimmed.
This dimming is indistinguishable from an analog incandescent bulb, thanks to a weird quirk of our anatomy.
Analog dimming adjusts the LED current level, which reduces the amount of light an LED produces. This seems simpler than PWM but has some notable limitations. With reduced power supply, the color of the LED light can change.
Which LED dimmer should I choose?
The standard dimmer switch allows you to adjust light levels from bracingly bright to total darkness in a few seconds.
But how do you know what type of dimmer to choose? If you just want a recommendation on LED dimmers, jump past this section to our suggestions below, including our own dimmer available here.
For those interested in dimming technology, there are two main types of modern dimmer: the leading-edge dimmer and the trailing-edge dimmer.
Leading-edge dimmers are the most commonly installed dimmer in the United States and worldwide.
The simplest of these use a TRIAC (Triode for Alternating Current) which cuts the AC waveform at the start (the leading edge) and reduces the amount of current that reaches the light bulb.
This works well for high voltage applications, making incandescent bulbs dim effectively, but it may produce a buzzing or flickering. This comes from vibrations in the bulb caused by the chopped-up AC coming from the TRIAC.
If an LED bulb is used in this system, you might notice flickering caused by this same effect.
Further, these leading-edge dimmers are designed for resistive loads, not the low-voltages needed for an LED. This may lead to poor dimming performance and shortened LED lifespans. However, specific TRIAC dimmers for LEDs are available without these downsides.
A trailing-edge dimmer is less common, as it was discovered long after leading-edge dimmers became standard.
Instead of cutting the waveform at the start, a trailing edge cuts the waveform at the end when the waveform is already decreasing.
This avoids the large jump in voltage created by leading-edge dimmers, which cause issues with LEDs. It also has the added benefit of not buzzing.
Our LED Dimmer recommendations
We suggest using modern dimmers made specifically for LED lights. Any older dimmers, or dimmers made for traditional lighting, may cause issues (e.g. flickering, buzzing) when used with LEDs.
You can purchase a Hyperikon dimmer here, which works with incandescent and halogen bulbs of up to 700W, and dimmable LED and CFL lights of up to 150W. However, we don’t recommend mixing them in one lighting system.
Otherwise, here are some dimmers that we have found to be compatible with most of our 120V LED lights:
Please note that this list is not exhaustive. If you are considering a specific dimmer we encourage you to try it and/or contact our customer service team with questions.
Checklist for Your Dimmable LED Lighting Setup
As we’ve seen, whether or not your current LED light bulbs are dimmable or not depends on your lighting setup, your dimmer switches, and a range of other factors.
If you’re looking to establish a dimmable LED lighting set-up, here’s a reminder of what you’ll need to ask yourself:
- Does the LED bulb you are buying say ‘dimmable’ clearly on the package? If not, is there a technical specification available?
- Are you buying an LED that requires a driver? If so, is the driver dimmable and appropriate for the LED you wish to install? Carefully check the technical specifications for details.
- Are your dimmers appropriate for LEDs? It’s important to pick a dimmer that is designed for the lower voltage load of LEDs. This might mean replacing old leading-edge dimmers with trailing-edge dimmers.
- Are you buying from a brand you trust? Low quality LED bulbs often contain cheap drivers, leading to poor dimming performance.
- Avoid mixing and matching LEDs from several manufacturers on the same dimming circuit. Each LED will be designed differently and send a different load signal to the dimmer. This will likely cause flickering.
Follow this checklist and you’ll increase your chances of a high-quality and flicker-free LED dimming experience.