Dimming used to be simple: fit a dimmer switch and the old bulbs dimmed. LED bulbs use far less power and work differently, so the bulb, the light and the switch all need to suit one another. Get it right and LEDs dim smoothly; get it wrong and you may see flicker, buzzing, or lights that will not dim all the way down.
Why Do My LED Lights Flicker on a Dimmer?
Usually because one of three things is not made to dim LEDs: the light, the bulb or the dimmer switch. Or the bulbs together draw less than the dimmer's minimum load. All three must match.
1. The light fitting. Most decorative lights with a replaceable bulb will dim, as long as the bulb and switch do. Lights with built-in (integrated) LEDs dim only if the product says so. Every product page on our site states whether the light is dimmable.
2. The bulb. An LED bulb must be marked dimmable. A non-dimmable LED bulb on a dimmer can flicker, buzz or fail early.
3. The dimmer switch. Older dimmers were designed for much higher loads than LED bulbs draw. Use a dimmer made for LEDs, often called an LED dimmer or a trailing-edge dimmer, and check its minimum load.
- A dimmable light
- A dimmable bulb
- An LED dimmer switch
- Smooth dimming
What Is a Dimmer's Minimum Load?
It is the least power, in watts, that a dimmer needs on its circuit to work smoothly. A dimmer has a minimum and a maximum load, both shown in watts. LED bulbs draw very little - five 4W bulbs is only 20W - which can fall below an older dimmer's minimum. When that happens the lights may flicker or not switch off completely.
Rule of thumb: add up the wattage of every LED bulb on the circuit and make sure the total sits comfortably within the dimmer's LED range. If you are unsure, your electrician can check the switch.
Work It Out
Dimmer Load Check
Your lights
Your dimmer
The minimum and maximum are printed on the dimmer or its box, usually as an LED or trailing edge rating.
is below this dimmer's minimum. The lights may flicker or not switch fully off. Add bulbs to the circuit or choose a dimmer with a lower minimum. is over this dimmer's maximum. Use a dimmer with a higher LED rating, or split the lights across two dimmers. is within this dimmer's LED range. Also check the bulbs and the light are marked dimmable.
Number of bulbs times watts each, compared with the LED range printed on the dimmer.
What Is an LED Driver?
A driver converts mains power into the low-voltage direct current that LEDs run on.
- Mains power
- Driver
- LEDs
- Low-voltage power
- Replaceable LED bulbs have the driver built into the bulb, so you do not need to think about it.
- Integrated LED lights have a driver inside or beside the fitting. If the light is dimmable, its driver must be too, and it may need a particular type of dimmer. The product page will say.
- Low-voltage lights (some spotlights and outdoor lights) may need a separate driver or transformer. We list it where one is needed.
Will My LED Bulbs Dim? A Quick Checklist
- The light says dimmable.
- The bulbs say dimmable.
- The dimmer is LED-compatible, and the total wattage fits within its LED range.
- All the bulbs on the circuit are the same type and ideally the same brand.
Adding Bulbs to Your Order
Every light on our site lists the bulb cap it takes, how many bulbs it needs and the maximum wattage. Where a light takes replaceable bulbs, you can add matched dimmable bulbs to your order in one tick.
Need a Hand?
Call our lighting team on 0113 2818 343. Tell us which light and dimmer you have, and we will help you choose bulbs that work together.
