Battery Equivalents and Replacements

Lights Dim and Flicker When Vacuum Turns On: Why and What to Do?

When lights dim and flicker as a vacuum or other large appliance turns on, it may indicate an electrical issue that should be addressed.

This issue doesn't have to be serious, but until it is resolved, consider it as a very serious issue.

Published: December 20, 2023.

vacuum cleaner

Why Do Lights Dim and Flicker When Vacuum Turns On?

The answer to this question is very simple: fluctuations in voltage supply cause lights to dim and flicker. Why does voltage fluctuate when a vacuum cleaner or some other powerful appliance starts, that is a difficult question to answer. And the worst of all, sometimes there might be several causes combined.

Here's what you can consider:

Circuit Overload

Many times, when a high-powered appliance like a vacuum is used, it can cause a temporary dip in the electrical supply (voltage drop), leading to the dimming of lights. This can be more pronounced if the vacuum and the lights are on the same circuit and the vacuum is full size, upright, or canister, 12-14 Amps unit.

Loose Connections

Loose electrical connections can be a fire hazard and should be inspected by a professional. A loose connection could be in the outlet, breaker box, or elsewhere in the home's wiring.

As the current passes through loose connections, voltage variations appear, causing voltage fluctuations in the circuit, causing light bulbs to dim and flicker, and vacuum cleaners and other appliances to operate inconsistently and unpredictably.

Damaged Wiring

At homes that have or have had issues with mice, rats, and other similar pests, it is possible that wires are damaged, and they can't transfer enough power/current to all loads when the vacuum cleaner is turned on.

damaged wires

Check the Service Panel

It's possible that the circuit breaker is either aging or is close to its capacity. The vacuum cleaner may be drawing just enough additional current to cause a noticeable effect on the lights.

Inadequate Home Electrical System

Older homes, in particular, may not have been designed for the electrical loads of modern households. If your electrical panel, wiring, or service is outdated, it might be time to consider an upgrade.

Voltage Fluctuation

Some voltage fluctuations can be caused by external factors, such as when the electric company is adjusting the supply or due to local demand. If the problem persists, you might want to contact your service provider.

Other Appliances

If you've recently added other large appliances or numerous smaller ones, your electrical system might be working closer to its capacity than before.

Check the Appliance Itself

Ensure that the vacuum or any other large appliances causing the flicker aren’t faulty. Faulty devices can draw irregular currents and could potentially damage your home's electrical system or pose a fire risk.

For example, when a vacuum's motor starts, it draws for a few very short moments more current. However, if there is an issue with lubrication or its bearings, the motor may draw excess current constantly - unless the vacuum cleaner has a properly dimensioned internal circuit breaker. However, not all vacuums have it.

Quality of Bulbs

Some light bulbs, especially older CFLs or low-quality LED bulbs, might be more prone to flickering than others. Upgrading to high-quality LED bulbs might reduce or eliminate the issue.

light bulbs

How To Solve Dimming and Flickering Lights Caused By Vacuum Cleaner

Solving this issue depends on determining first what is causing this issue. Sometimes, it may be something obvious, but sometimes it is required to contact professionals and let them do the job.

Check the Vacuum Cleaner

If you notice lights dimming and flickering when turning on your vacuum cleaner, the first thing to do is to turn off the vacuum and unplug it from the power outlet.

After that, check if there are debris or clogs in the vacuum if the dirt bin/vacuum bag is full, and if the air filters are dirty. Also, check the unit for any additional signs of problems or even a smell - for example, a burning smell may indicate an issue with the motor.

full vacuum bag

Change the Power Outlet

If everything seems alright with the vacuum, plug the vacuum cleaner into another power outlet, preferably protected by another electric breaker. If everything is alright in this situation, you have isolated a problem in your home electric circuit, which should be addressed/checked by a licensed electrician - better safe than sorry!

Professional Inspection

If you're unsure about the cause of the flickering or the dimming, consulting with a licensed electrician is always a good idea. They can identify if there are any issues with your home's electrical system.

electric breakers

Spread Out Large Appliances

If possible, avoid using multiple large appliances at the same time or move the vacuum to an outlet on a different circuit to see if the issue persists.

Consider an Electrical Upgrade

If your home's electrical system is older or not equipped to handle the modern electrical loads, it might be worth considering an upgrade. This might involve increasing the capacity of the service panel or adding additional circuits.

Monitor the Situation

If the issue is infrequent and doesn't seem to pose an immediate concern, monitor it. If it becomes more common or if you notice other electrical anomalies, then it's time to take action.

current check

Always prioritize safety. If you notice any burning smells, see sparks, or experience frequent circuit breaker trips, turn off the vacuum (or any other problematic appliance), unplug it from the wall, and seek professional help immediately.