How to Clean a Dryer Vent From Outside, According to Experts

The National Fire Protection Association estimates that U.S. fire departments respond to an average of 13,820 structure fires involving clothes dryers each year. And more than 30 percent of the fires are caused by a failure to clean the vent, the NFPA reports. 

“The dryer uses extreme heat to dry the clothes,” explains Robert Chittenden, who runs a dryer vent cleaning company called TheLintGuys. “With lint being as flammable as charcoal, when the heating element works too hard and causes a spark, the two work together like napalm.”

To help keep your home and the loved ones inside safe, here's a step-by-step guide for cleaning your exterior dryer vent, the required tools, and how often you need to do so.

How Improved Air Flow Affects Performance

Your dryer relies on airflow: The dryer draws dry air in, heats it, blows it through your clothes to absorb moisture, and then pushes that hot, moist air out through the vent. With a clean vent, it’s a simple, smooth process, and your laundry dries in a single cycle.

However, when the vent is partially clogged, the moist air is unable to exit properly. “This causes it to recycle within the drum,” explains Martha Gonzalez, cleaning expert and owner of Austin Cleaning Service. “Your clothes aren't dry after a single cycle, so you run it again, and that second cycle is wasted energy—plus wear and tear on the motor and heater.”

A clogged dryer vent can significantly raise energy costs. “With a clean vent, your dryer operates in short cycles, uses less energy, and doesn't put as many hours on its internal parts,” Gonzalez says. “This means your dryer will last longer before it needs to be repaired or replaced.”

How Cleaning Lint Reduces Fire Risk

Lint is probably the most flammable household item. “Your dryer creates lint with every single load, but the lint trap catches most of it,” Gonzalez says. “However, some lint always escapes and accumulates in the vent duct. As this build-up increases, it narrows the airway and causes heat to focus in the duct instead of venting outside.”

At some point, when the heat is concentrated enough around the pocket of trapped lint, it only takes a small spark or prolonged high temperatures to ignite it. “Removing the lint from the area where the heat occurs eliminates the possibility of a fire occurring,” Gonzalez continues. “The dryer operates normally, the hot air vents correctly, and the conditions leading to a fire don’t happen. It’s one of the simplest ways to prevent a fire and can be done in under an hour.”

How to Safely Clean an Exterior Dryer Vent

You can clean a dryer vent yourself as long as the run is short and you know where the lint gets caught, says Taylor Riley, partner at Stay Clean Solutions Commercial Cleaning. 

Here are the steps to take to clean your exterior dryer vent.

1. Prepare Your Dryer: Unplug the unit, pull it six inches forward, and turn off the gas supply knob on the unit, if applicable. “Vacuum the lint trap housing with a long crevice tool,” Riley says. “That keeps loose lint from falling down the duct when you detach it.”
2. Find the Exterior Cap: Locate the exterior vent cap outside of the house. “Many times the vent caps are secured with a few screws, or simply pop off,” says Gonzalez. “Remove the cap and put it somewhere safe.”
3. Start From the Inside Out: Disconnect the flex hose and run a 20-foot drill brush kit from the inside out. “The key is slow rotations and a vacuum at the port so you are not blowing lint into the laundry room,” Riley says.
4. Clean From the Outside: Now, feed the brush into the duct opening from the outside. “Rotate the brush while feeding it into the duct to loosen any lint that may be stuck to the inside of the duct,” Gonzalez says. “Continue to feed the brush into the duct in a back and forth motion, using additional rod extensions until you reach the end of the duct.”
5. Vacuum Thoroughly: Next, use a vacuum with a narrow hose to suck out the lint that was loosened by the brush. “Use a damp cloth to wipe the exterior of the vent cap to remove any dirt or spider webs,” Gonzalez instructs. “Also make sure that the flap opens and closes easily. Once you verify that everything is okay, replace the vent cap.”
   

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Suggested Cleaning Frequency

Clean the vent thoroughly at least once a year if you’re doing an average amount of laundry. “If you have a big family and are doing lots of laundry on a regular basis or if you have pets that contribute to the amount of hair and fiber in your laundry, clean it every six months,” Gonzalez suggests. “Always clean the lint trap after every single load. A clogged trap causes more lint to enter the duct system faster,” she adds.

Every couple of months, visually inspect the exterior vent. "While the dryer is operating, walk outside and look at the vent," says Gonzalez. "The flap should be opening, and you should be able to feel the flow of hot air. If the flap is hardly opening, or you can barely feel any airflow, it’s time to clean."

Warning Signs It's Time to Clean

It may pay to up your cleaning frequency. "If what used to dry in 45 minutes is now taking 75 minutes, that indicates the airflow is limited," Gonzalez explains.

The most dangerous warning sign that it's time to clean your exterior vent, however, is a burning odor that occurs when the dryer is running. "Immediately stop using the dryer and clean the vent before using the dryer again," says Gonzalez.

Other warning signs include: 

• The dryer seems unusually hot to the touch after a cycle 
• Your laundry room seems more humid than usual
• There is visible lint accumulation around the exterior vent opening on the outside of the home 
• The vent flap is unable to open while the dryer is running 
• You're seeing higher than normal energy bills
  

When to Call a Professional

If the dryer duct has more than two elbows, runs through the roof, or was retrofitted with foil flex, our experts advise homeowners to call a professional. As someone who has seen countless DIY jobs, there’s always something that can be missed if the dryer vent is not camera-scoped, Chittenden warns.

"You can do the first pass yourself," Riley says, but "90-degree bends hide lint and need a stronger vacuum." Best to leave it to those who have the proper tools and experience to get the job done right—the first time.