Why LED Lights Flicker or Buzz on a Dimmer (and How to Fix It)

You switched to LED bulbs to save energy, and now the lights flicker, buzz, or snap from dim to bright when you slide the dimmer. This is one of the most common lighting calls we get from Newnan homeowners, and the good news is that it usually comes down to a mismatch between the bulbs and the dimmer, not a dangerous wiring problem. Here is how our licensed electricians at Shocking Electric Solutions, Inc. sort out the cause, and when it is time to have a professional take a look.

Why LEDs and Older Dimmers Do Not Always Get Along

Many dimmers installed before LEDs were common were designed for incandescent and halogen bulbs. Those bulbs draw a lot of power, so the dimmer was built to handle a heavy, steady load. An LED bulb draws a small fraction of that power and has its own electronics inside, called a driver. When an old dimmer and an LED driver are not designed to work together, you can get:

• Flickering or pulsing, especially at the low end of the dimming range
• A buzzing or humming sound from the bulb, the fixture, or the switch
• Lights that will not dim much at all, or that shut off before they get dim
• Lights that pop on at full brightness or glow faintly when the switch is “off”

Step 1: Make Sure the Bulbs Are Actually Dimmable

Not every LED bulb is made to dim. Check the package or the base of the bulb for the word “dimmable.” A non-dimmable LED on a dimmer circuit will often flicker or buzz no matter what dimmer you use, and it can shorten the life of the bulb. If the bulbs are not dimmable, replace them or have the dimmer swapped for a standard switch.

Step 2: Check Whether the Dimmer Is Rated for LEDs

Turn off the light and look at the dimmer itself, or the box it came in. LED-compatible dimmers are usually marked for LED or CFL loads, and many list both an incandescent rating and a lower LED rating. If your dimmer only lists an incandescent wattage, it is likely the source of the problem. Replacing it with a dimmer designed for LED lighting fixes the issue in most homes we see.

Step 3: Think About How Many Lights Are on the Dimmer

Load matters in both directions:

• Too little load: A dimmer controlling only one or two small LED bulbs may fall below its minimum load, which can cause flicker or a faint glow when off.
• Too much load: A dimmer controlling a long run of recessed lights can exceed its LED rating. Dimmers installed side by side in the same box often have to be derated, so their real capacity is lower than the number printed on the front.

An electrician can total up the fixtures on the circuit and pick a dimmer sized correctly for the job.

Step 4: Do Not Mix Bulb Brands on One Dimmer

Different LED brands, and even different models from the same brand, use different drivers. When you mix them on one dimmer, some may dim smoothly while others flicker or turn off early. Using the same bulb model on the whole circuit gives the most even results. For integrated LED fixtures, such as wafer-style recessed lights, check the manufacturer’s list of compatible dimmers.

Step 5: Try the Low-End Trim Adjustment

Many LED dimmers have a small adjustment, often a dial or a setting in the app for smart dimmers, that sets how low the light can go. If your lights flicker or shut off near the bottom of the range, raising the low-end trim a little often stops it. Follow the instructions that came with the dimmer.

When Flickering Is Not a Dimmer Problem

If lights flicker on circuits that do not have dimmers, in several rooms at once, or when large appliances like the HVAC or a dryer kick on, the cause is probably somewhere else in your electrical system, such as a loose connection, an overloaded circuit, or a problem at the panel or service. Our guide to lights flickering in your house in Newnan, GA walks through those causes.

Signs You Should Stop and Call an Electrician

A dimmer can feel slightly warm to the touch during normal use. These signs are not normal:

• The dimmer or wall plate is hot, discolored, or melted
• You smell burning plastic near the switch or fixture
• You hear crackling or sizzling, not just a light hum
• The breaker trips when you use that light

If you notice any of these, turn the light off at the switch, shut off the breaker for that circuit if you can do so safely, and have a licensed electrician check it before using it again.

A Note on Smart Dimmers and Three-Way Switches

Many smart dimmers need a neutral wire in the switch box, and some older Newnan homes do not have one at every switch location. Lights controlled from two or more switches (three-way or four-way circuits) also need dimmers and companion switches that are designed to work together. These are common reasons a do-it-yourself smart dimmer upgrade does not work as expected. Our team handles dimmer switch installation in Newnan, GA, including smart and multi-location dimmers.

Planning New LED or Recessed Lighting?

The easiest way to avoid flicker is to choose the fixtures and dimmers together from the start. When we install LED and recessed lighting in Newnan, GA, we match the dimmers to the fixtures and size them for the number of lights on each circuit, so your lighting dims smoothly and quietly.

Call Shocking Electric Solutions, Inc.

If your LED lights are flickering, buzzing, or not dimming the way they should, call Shocking Electric Solutions, Inc. at (678) 552-9399 or text (470) 516-7261 to schedule a visit. Many customers prefer texting. We are based at 1002 Highway 16 W, Suite A, Newnan, GA 30263, and serve Newnan and communities within about 40 miles. Learn more about our licensed electricians in Newnan, GA.

Still not sure what is causing the problem? Our electrical troubleshooting and repair in Newnan, GA service finds the real cause and fixes it safely. See also our page on lights flickering.