There’s a Hidden Fire Hazard in Your Bathroom You Might Be Ignoring

Over the years, most mechanical systems in your home will get serviced or otherwise checked for safety. One that probably gets neglected, however, is the exhaust fan in your bathroom. And if something goes wrong with that, it could start a house fire.

“As people adopt more automated systems — like smart thermostats, smoke detectors and air purifiers — traditional, unconnected devices like exhaust fans fall out of regular inspection and maintenance routines,” says Jon Gilbertson, president of Chris Heating & Cooling. “This gap creates a hidden vulnerability in what we think of as safe.”

This viral TikTok video from the wife of a firefighter points out how dust accumulates over the years in our bathroom fans, and how that creates what she defines as the “number one fire danger in your house.”

@unhingedreviewswjess Google will tell you the most common house fire is a kitchen fire. That may be the most common way fired get *started* in houses, but not how they burn to the ground. RJ said kitchen fires are usually put out by the time they arrive on scene. It’s not only RJ’s opinion that this is the most dangerous fire in your home, but I met a retired FF who was working as a Fire Safety guy that worked for the city that 100% agreed with him. Exhaust fans accumulate sooo much dust and dirt over the years. I prefer to replace them over cleaning them. They’re not terribly expensive or difficult to replace. A lot easier than replacing your home, and not to mention everything in it!! Stay safe, friends. #firefighter #firefightertiktok #firefighters #homeimprovement #renovation #diyproject #homeproject #homerenovation ♬ Suspense, horror, piano and music box – takaya

Here’s what can go wrong with bathroom exhaust fans, and how to prevent them from starting a fire in your home.

How Do Exhaust Fans Become a Fire Hazard?

This happens partly because we often overlook cleaning bathroom exhaust fans. They tend to accumulate dust. As that builds up on the fan blades and vents, the motor has to work harder to move air, which can cause it to overheat and cause the bearings to wear. All of this has the potential to spark a fire, especially if the motor shorts out.

Overusing the fan adds to the danger. “Because they’re almost always plugged in, any damage in the wiring or circuit can cause sparks that can spread into a fire,” says Timothy Wood, founder of Fix It Today.

Old and improperly installed wiring can also create problems, especially if the insulation on the wires degrades or the connections loosen. Gilbertson says this danger can be compounded by bathrooms’ high humidity.

Why Are Exhaust Fan Fires So Dangerous?

Exhaust fan fires commonly get out of control because they start above the ceiling, out of view and out of reach from fire detectors. In a confined area, like an attic, they are also likely to ignite insulation and other materials. Besides causing structural damage, those can create toxic smoke that seeps into living areas.

Exhaust fan fires are “particularly dangerous because the fan’s design and placement create a chimney effect,” says Gilbertson. “When a fire starts in or near the fan, the heat naturally rises through nearby ductwork, amplifying the fire’s intensity and allowing flames to move quickly into other parts of the home.”

How to Avoid Exhaust Fan Fires

We don’t want to get rid of our exhaust fans, since they keep our bathrooms from getting moldy, but we can keep them from being dangerous by:

• Making sure the vent pipe, discharge end and fan blade are free from obstruction;
• Cleaning the system out annually and checking wires and circuits for signs of wear and damage. To clan them properly, remove the exhaust fan cover and use a brush or vacuum to remove any debris from both sides of the cover and any accessible portion of the fan housing, says Kevin Busch, president at Dryer Vent Wizard.
• Checking installation, with the exhaust fan vent pipe being less than 15 feet;
• Installing a newer fan, with thermal protection, which shuts down if the fan overheats;
• Making sure they’re properly vented, with exhaust not going directly into the attic, but rather outside of the home through a wall, soffit or roof.

“We find many bath fans that are not exhausted using the proper materials, which can allow fires to burn through the venting increasing the risk of a fire spreading,” says Busch.

Also, it’s very important to use exhaust fans in moderation and turn them off promptly. “Put the fan on a timer that only allows 30 minutes of use at a time,” says Todd Tripp, a home improvement expert with JustAnswer.com. “This lets the fan cool down and not run constantly as fans are easily left on continuously.”

Wood also recommends providing a dedicated circuit for the exhaust fan to avoid overloading. “If you must connect it to a circuit that services several other devices, make sure the total load doesn’t exceed that circuit’s capacity,” he says.
Lastly, consider installing a humidity sensor fan that runs only when necessary. This will reduce wear and prevent constant dust buildup, says Gilbertson, “a smart, hands-off solution for busy households.”

About the Experts

• Timothy Wood is founder and CEO of Fix It Today, an online home repair scheduling and estimate service based in the Dallas-Fort Worth area.
• Todd Tripp is a general contractor and founder of Trip Mills Builders in upstate South Carolina, and a home improvement expert with JustAnswer.com.
• Jon Gilbertson is president and CEO at Chris Heating & Cooling, a family business based in Chicago, where he began his career as an HVAC technician in 2015.
• Kevin Busch is president of Dryer Vent Wizard, a Neighborly Company and national home service franchise specializing in professional dryer duct and vent cleaning, inspection, repair and maintenance services.