Why Are My Lights Flickering?

All you want to do before drifting off to sleep is finish the last chapter in that great book you’re reading. But there’s a problem: The lightbulb in the lamp on your bedside table is flickering.

What should you do? Ignore it? Switch to an e-reader? Take your book to another room? All are viable options, but there is a better solution — one that may even allow you to keep reading right where you are. Sometimes the fix is just that easy.

What Causes Lights to Flicker?

We’re talking about simply switching out your lightbulb, because a flickering light often indicates that the bulb itself (not the lamp or your home’s entire electrical system) is nearing the end of its life span.

“One of the most common reasons, and you should always look for the obvious things first, is that the bulb is about to blow,” says Terry Duncan, CEO of Mr. Electric in Inglewood, California. If this is the case, replacing the old lightbulb with a new one will do the trick, Duncan says.

You can also try just screwing the bulb in a little tighter to see if that helps. Sometimes a loose bulb will flicker, too, says Christopher Haas of Haas & Sons Electric in Pasadena, Maryland.

The caveat to all this is what type of lightbulb you’ve got in the lamp, Duncan says. The old and/or loose bulb problem usually only applies to incandescent bulbs. If the flickering light in question is an LED, you can certainly try switching out the bulb to see if it helps. But chances are, you’ll need to investigate further.

Less Common Causes of Flickering Lights

You’ve replaced your bulbs and the flickering continues. Now what?

Here are a few things that could be going on:

Loose wires and/or electrical connections: Duncan says this is especially likely if you recently had electrical work done in your home by someone who failed to properly connect or secure all the wires. If you suspect this, Duncan recommends calling a licensed electrician to help with the investigation, because electrical fires can sometime happen under these conditions.
Faulty fixtures: Has the light fixture seen better days? If it’s old, broken, rusty or failing from some other reason (like a cracked cord or loose switch), flickering may result. To test this, Haas suggests removing the bulb and replacing it with one you know works. If the flickering continues, it could be your fixture. You can start by installing a new fixture. Then if the new fixture flickers, it’s time to call a licensed electrician.
Incompatibility with LED bulbs: Some lights, ceiling fans in specific, may not operate correctly when using LED bulbs. If you’re using LED bulbs and the appliance, or fixture flickers, try changing back to a regular incandescent bulb. But, that’s not all that might not work correctly with newer, LED bulbs. The light switch itself may not agree with the use of LED bulbs. We’ve found this to be the case mainly when using light switches that also have a dimmer controller.
Large motor-operated appliances: Lights may flicker momentarily when large motor-operated appliances are turned on. For example, when the AC unit starts up, it draws a lot of current, which can cause lights to briefly flicker. When you experience any momentary flicker, check what else is going on in your home. Did someone start a cord-connected vacuum cleaner? Is someone in the workshop using a cord-connected power tool or air compressor? Did someone fire up the dishwasher or garbage disposer? Momentary light flicker from starting powerful appliances or tools is usually not a concern.
Circuit overload: Occasionally, Haas says lights will flicker because an electrical circuit is running too many amps. If your kitchen lights dim when you use your toaster, your toaster might be too powerful for the circuit it’s on. To verify, plug something else that runs on a similar number of amps into the outlet. (All electrical appliances should have a label, nameplate, embossing or similar marking with the rated voltage and amperage. Alternatively, some electrical apparatus might be labeled in voltage and wattage.) If the same thing happens, it could be a circuit overload. Better call a licensed electrician for help with this one. The problem also could be the toaster itself. Try plugging the toaster or any problematic small appliance into other outlets to see what happens. If flickering occurs no matter where you are in the house, it could be time to toss the appliance.

Are Flickering Lights Dangerous?

Aside from cases of loose electrical connections, flickering lights are rarely imminently dangerous, Duncan says. However, if changing lightbulbs, replacing fixtures and/or investing in a new toaster prove fruitless, don’t let it go. Seemingly minor electrical problems can build over time, eventually creating a potential disaster.

“Call somebody out to take a look,” Duncan says. “It is always best to be safe.”

How Do I Stop My Lights From Flickering?

To review, start with the simple fixes. Make sure your lightbulb is screwed into the fixture properly and, especially if it’s an incandescent bulb, swap it for a new one. Check to see if the fixture is the issue, and make sure your bulbs are compatible. If these options don’t fix it, check the load on your circuits and consider calling an electrician to help you sort out the issues.