Dryer vent cleaning: how often to do it, how to check your vent and when to hire a pro

The lint trap catches most of the lint, but not all of it. The rest travels into the vent pipe behind the dryer, where it builds up slowly, blocks airflow and can overheat. A clogged vent is one of the most preventable fire hazards in a house, and it takes only a few minutes to check.

Why it matters

According to a U.S. Fire Administration report covering 2008 to 2010, an estimated 2,900 clothes dryer fires in residential buildings are reported to U.S. fire departments each year, causing an estimated 5 deaths, 100 injuries and $35 million in property loss. The top factor was failure to clean, at 34 percent of fires. Dust, fiber and lint were the first items ignited in 28 percent of fires, and fires were more common in the fall and winter, peaking in January. The National Fire Protection Association (NFPA) also names failure to clean as the top cause of home dryer and washer fires.

How often to clean

• After every load: clean the lint filter, before or after each cycle. Remove any lint around the drum as well.
• Every few months: scrub the lint filter with a nylon brush and warm soapy water. The U.S. Fire Administration suggests brushing it at least every 6 months, and more often if it gets clogged.
• Once a year: clean the vent pipe from the back of the dryer to the outdoor opening, or have a professional do it. The NFPA and the U.S. Fire Administration both say to clean the vent once a year, and sooner if drying takes longer than normal.
• Whenever drying times get longer: check the vent right away.

Signs of a clogged dryer vent

• Drying takes longer than it used to. The NFPA and AHAM both say to clean the vent promptly when drying times increase.
• Little or no air comes out of the outside vent hood while the dryer runs. The AHAM trade association suggests making sure you can feel air flowing out of the vent.
• The flap on the outside vent doesn’t open when the dryer runs.
• Lint buildup around the outside vent, or a vent duct that is crushed or restricted behind the dryer.

How to check your vent

• Pull the dryer away from the wall, unplug it (and for a gas dryer, don’t disturb the gas connection) and look at the duct behind it. It should not be crushed, kinked or restricted.
• Look at the material. Rigid or flexible metal venting is recommended; plastic or vinyl ducts are not, and even flexible foil can twist and trap lint. Use the shortest, straightest run possible.
• Go outside and check that the vent flap opens while the dryer runs, and that it is not covered with snow. Don’t cover the vent with a wire screen or cloth, which can collect lint.
• Vent the dryer to the outdoors, not into an attic, crawl space or garage. A typical load of laundry releases about a gallon of water as vapor.

Can you do it yourself?

Many homeowners clean the vent with a brush kit that attaches to a drill, or a vacuum with a long hose. If the run is short and accessible, that can work. Be careful with gas dryers, and don’t disturb the gas connection. Consider hiring a pro if the vent is long, runs through a roof or upper floor, is crushed, or has tight bends, if your dryer is gas, or if clothes still take too long to dry after you clean it. NFPA suggests having a professional install and service the dryer; the AHAM trade association suggests a qualified technician clean the dryer interior and vent once a year.

Quick safety rules

• Don’t run the dryer when you leave home or go to bed.
• Don’t overload it, and don’t dry items that have touched flammable substances such as cooking oil, gasoline, paint thinner or alcohol.
• Keep the area around the dryer clear of boxes, clothing and other things that can burn.
• Install a smoke alarm in or near the laundry area, and a carbon monoxide alarm if your dryer is gas.

How to compare quotes for dryer vent cleaning

• Ask what the price covers: the full run from the dryer to the outdoor hood, the hood itself, and the inside of the dryer.
• Ask how they confirm the vent is clear afterward, such as an airflow reading or a photo.
• Ask whether they will replace unsafe plastic or foil duct and what that costs.
• Get the total price in writing before work begins.

Put it on the calendar

Set a yearly reminder, and an extra one if you notice longer drying times. A free Estodia account adds dryer vent cleaning to each home’s plan and lets you request quotes without sharing your phone number or email with pros.

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