Dimming LEDs can be tricky for a variety of reasons, and it can sometimes be difficult to pinpoint the source of the particular issue you're facing, like flickering. In this post, we'll zero in on one particular issue: a lack of load resistance.
Conventional (TRIAC) dimmer switches – the ones designed to work with incandescent and halogen light bulbs – require a certain amount of "holding current," or wattage in non-electrical-engineer terms, in order to work properly. When paired with an incandescent, the bulb draws enough voltage for the dimmer to work with and reduce. The control cuts the voltage, sending less to the lamp, or bulb, resulting in reduced light output (dimmed lighting).
That's a rough sketch of how conventional dimming works.
Here's the problem with trying to dim LEDs with those same TRIAC dimmers: LEDs draw significantly less current – an inadequate amount for the dimmer to properly work, or properly reduce the voltage going to the lamp. The dimmer has so little current to work with that whatever voltage it does reduce ends up manifesting in the LED bulb as choppy, resulting in flickering, or
So, the key is to supply sufficient load or current to the switch, which brings us to the premise of this article. Some electricians have experimented with adding a higher-wattage incandescent bulb to the same circuit where LEDs were being controlled by a dimmer. This draws adequate current to the TRIAC dimmer, allowing it to better reduce the voltage going to the lamps.
Can you fix LED flickering and other dimming problems by adding an incandescent bulb to the circuit?
The short answer to this question is yes, generally. The higher voltage drawn by the incandescent is often sufficient current for the dimmer to work properly. But this isn't always the case, nor does Regency recommend this as a long-term solution for your dimming issues. It's more of a "Band-Aid" fix than a cure.
Here are some drawbacks to remember if considering this solution:
- For visual purposes, we never recommend mixing different lamp types in the same room or area of a building, so you'd want the lone incandescent on the circuit to be in an inconspicuous spot.
- With this solution, you'll likely burn through four or five (or
manymore) incandescent bulbs by the time you need to replace a single LED, so you could have a fairly frequent occurrence of having a single burned out bulb. And when the lone incandescent burns out, it will cease to draw current to the circuit, which could cause your LEDs to begin flickering again.
- Generally, while this solution is attainable and seemingly easy on the front end, it can be high maintenance long-term.
Our customers have had varied results with this tactic, and it is not something we recommend.
Another, slightly better solution for adding resistance to the circuit is to buy a "load resistor," or a "dummy load." Without going into painstaking detail, a load resistor essentially serves the same purpose as the incandescent bulb in the solution described above – it simulates an electrical load, drawing sufficient current to the dimmer switch.
Between adding an incandescent bulb to the circuit and using a load resistor, the resistor is probably the preferred solution, as it's likely to require less maintenance long-term.
The long-term solution for dimming LEDs with no flickering
Though adding an incandescent bulb to the circuit and using a load resistor are both OK LED dimming solutions, they are only short-term fixes and don't get to the heart of the matter – incongruous pairing.
If you're not using dimmable LEDs with an LED-compatible dimming control, it will always take some level of twisting and modification to get the two to interact properly, and dim your lighting.
If your electrical work hasn't been updated in the last three to five years, the dimmer switches on your wall are likely TRIAC switches – designed to only work with incandescent lighting. And this is where problems come in.
All of the sudden, the LED retrofit you planned out and got a competitive quote for got more complicated and more expensive. It's no longer just a lamp swap, but now you need electrical work done and need to buy new dimmer switches to work with your new lamps.
We get the pain of that.
Just last weekend, I was installing a new light fixture in my kitchen.
The fixture was pretty inexpensive – just $105. I bought eight bulbs to pair with it, which
Ultimately, I spent more on my dimmable LED bulbs and LED-compatible dimmer switches than I did on the fixture itself.
But here's the good news: the fixture dims perfectly – smoothly and without any problems. And I know it will remain this way for a while, with no need for ongoing maintenance or readjustment. The bulbs will probably last me longer than my wife's satisfaction with the fixture, especially if we
The cost of retrofitting to a sustainable dimmable LED solution may be painful on the front end, but it's worth the savings and avoided maintenance headaches down the road.