How to Clean a Dryer Vent (and How Often)

This guide is for homeowners and renters who use a clothes dryer and want to lower the fire risk and keep loads drying on time.

A dryer pushes hot, damp air and loose fibers out of your home through a duct. When lint collects along that path, the air can’t escape, the dryer runs hotter and longer, and the lint itself becomes fuel. The U.S. Fire Administration (USFA) says you are at higher risk of a clothes dryer fire if you don’t clean your lint filter and dryer vents.¹ The good news: most of the job takes minutes. Here’s how to clean a dryer vent from the lint screen to the outside flap, how often to do it, and when to call a pro.

Why it matters

UL Solutions reports about 15,600 structure fires, 400 injuries and 15 deaths from clothes dryers each year, and cites the USFA estimate of more than $100 million in property loss annually.³ It also cites NFPA data showing failure to clean was a factor in 33% of dryer fires.³

CPSC explains how it happens: lint in the dryer or the exhaust duct blocks airflow, heat builds up, and that can start a fire.²

The quick answer

Every load: clean the lint filter before and after each cycle,¹ and never run the dryer without the filter in place.¹
Every few months: pull the dryer out, clean behind it and check that the duct isn’t damaged, crushed or restricted.¹
Every time you think of it: go outside while the dryer runs and make sure the vent flap opens.¹
Once a year: have the exhaust vent inspected and cleaned, as UL recommends.³

Warning signs your dryer vent is clogged

CPSC says that if clothes are still damp at the end of a normal cycle, or drying takes longer than usual, the lint screen or the exhaust duct may be blocked.² A second test from CPSC: with the dryer running, the outside vent should be releasing air. If it isn’t, the vent or duct may be blocked.²

Other signs, from our experience rather than the agencies:

The top of the dryer or the laundry room feels unusually hot.
There’s a burning or hot-lint smell.
Lint is collecting around the outside vent or under the dryer.
The outside flap stays closed, or barely moves, while the dryer runs.

If you smell burning, stop the dryer and don’t use it until it has been checked.

Step 1: the lint filter

Pull the screen out and remove the lint by hand before you start a load, and again when it finishes.¹

Our advice: dryer sheets can leave a waxy film on the screen that blocks air even when it looks clean. Every couple of months, hold the screen under the faucet. If water pools on it instead of running through, wash it gently with warm, soapy water and a soft brush, rinse it, and let it dry completely before you put it back. Check your manual first, since some makers give their own steps.

While the screen is out, look into the slot it sits in. Lint collects there too. A narrow vacuum attachment or a long, flexible lint brush reaches most of it.

Step 2: behind the dryer

Unplug the dryer first. For a gas dryer, follow the maker’s instructions before moving it, and be careful not to kink or strain the gas line. Slide the dryer out and look at the duct that connects it to the wall.

The USFA says to clean the back of the dryer, where lint builds up, and check that the venting isn’t damaged, crushed or restricted.¹ CPSC adds that you should keep the area around the dryer clear of clutter.²

Our advice for a do-it-yourself clean:

Loosen the clamps and pull the duct off the back of the dryer and the wall fitting.
Vacuum lint out of both openings and the floor behind the dryer.
Run a dryer-vent brush through the duct and as far into the wall pipe as it reaches. Kits with flexible rods that connect to a drill reach farther, but go slowly so the brush doesn’t come apart in the pipe.
Reconnect everything with the clamps tight and as few bends as possible, then push the dryer back without crushing the duct.

CPSC says that if you disconnect the duct to clear a blockage, reconnect it before using the dryer again.²

Step 3: the outside vent

Go outside while the dryer is running. The flap or louvers should open and you should feel air moving.¹ If not, the vent may be stuck with lint, ice or a nest. Our advice: clear what you can reach safely from the outside, and brush the last foot or two of pipe from the outside in. Don’t fit a screen over the opening; lint gets caught on it.

Which dryer duct to use

CPSC recommends replacing plastic or foil accordion-type duct with rigid or corrugated semi-rigid metal duct, because plastic and foil trap lint more easily and are more likely to kink or be crushed.²

UL notes that a flexible transition duct (the piece between the dryer and the wall) should be a single length of no more than 8 feet, and that maximum duct length and number of bends come from the dryer maker’s instructions.³ Our advice: the shorter and straighter the run, the less lint it traps.

How often to clean a dryer vent

Part	How often	Source
Lint screen	Before or after every load	USFA, CPSC¹²
Behind the dryer and transition duct	Periodically; our advice: every 3 to 6 months	USFA, CPSC¹²
Full exhaust vent	Inspect and clean once a year	UL³
Inside the dryer cabinet	Periodically, by a qualified technician	CPSC²

UL adds that the right inspection schedule depends on how much you use the dryer, the length and shape of the duct, and the dryer’s age and type.³ Our advice: a big household with daily loads, or a long run to a roof vent, needs more frequent cleaning.

When to call a professional

The USFA recommends having your dryer installed and serviced by a professional.¹ Our advice: call one when the duct runs through an attic, a ceiling or a long wall cavity, when it exits on the roof, when loads are still slow after you’ve cleaned what you can reach, or when you find a crushed section inside a wall.

Clothes that need extra care

CPSC warns that clothes stained with volatile chemicals such as gasoline, cooking oil, cleaning agents, or finishing oils and stains can be a fire risk. Wash them more than once if possible and preferably air-dry them. If you must use the dryer, use the lowest heat and a cycle with a cool-down period, and don’t leave the dried items sitting in the dryer or piled in a basket.²

Dryer vent checklist

Clean the lint screen every load; never run without it.
Wash the screen if water won’t pass through it.
Pull out the dryer, vacuum behind it and check the duct.
Rigid or semi-rigid metal duct, not plastic or foil.
Outside flap opens and air flows while running.
Full vent inspected and cleaned once a year.

How to Clean a Dryer Vent: A Safer Laundry Routine