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How do you clean a dryer vent duct?

Updated August 2026

30–60 minutes · Easy DIY

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The lint screen is not the job. Brushing the duct end to end is, and it runs 30 to 60 minutes once a year with a $25–40 rotary kit and a drill: disconnect the dryer, work the brush in from both ends, and vacuum what falls out. The U.S. Fire Administration counts roughly 2,900 home clothes dryer fires a year, with failure to clean the leading cause. The everyday penalty arrives long before that, since a restricted duct roughly doubles drying time and cooks the heating element, a $150–350 part.

What you need

Before you start: On a gas dryer, close the shutoff valve before you move the machine, and never let the flexible gas connector kink, twist, or take the dryer weight. When you reconnect, brush soapy water over the fitting and watch for bubbles, and if you smell gas at any point, leave the house and call the utility from outside. Unplug an electric dryer rather than trusting the power switch. Do not reinstall plastic or vinyl duct: it is banned by code for dryers, it sags into lint traps, and it burns. Lint is fuel, so keep it away from a gas burner or pilot.

Steps

  1. Unplug an electric dryer. On a gas dryer, also close the shutoff valve on the gas line behind the unit before anything moves.
  2. Walk the dryer out 2 to 3 feet, loosen the clamps, and pull the transition hose off both the dryer stub and the wall duct. Support the gas flex connector so it never bends sharply.
  3. Vacuum the dryer exhaust stub, the transition hose, and the floor behind the machine, where a surprising amount of lint collects against the baseboard.
  4. Go outside and take the cover or flapper off the vent hood, then vacuum the lint you can see and reach.
  5. Chuck the brush onto the drill and feed it into the duct from the outside on low speed, turning clockwise only. Reverse rotation unthreads the rods and leaves one stranded in the wall.
  6. Work in and out in 6 to 12 inch strokes, adding a rod at a time until the brush reaches the far end, then draw the whole assembly back out slowly.
  7. Repeat from the inside end, then vacuum both openings. A duct that has gone a full year gives up a grocery bag of lint, and that is normal.
  8. Reconnect with clamps and seal the joints with foil tape. Replace any crushed white vinyl or thin foil-flex hose with rigid or semi-rigid metal, and keep the transition run as short and straight as the space allows.
  9. Slide the dryer back leaving 4 to 6 inches of clearance, restore power and gas, and run 15 minutes on air fluff. Go outside and confirm the hood flapper stands open with strong airflow behind it.

Or hire it out

A vent cleaning service charges $90–170 for a standard first-floor run, and $200–350 for a long roof-terminated duct or a second-floor laundry with several elbows. The brush kit pays for itself on the first use and lasts a decade.

Done. Now the part everyone skips: doing it again on schedule. Log it in OnOtto and the next reminder for dryer vent cleanings sets itself.

Log this task, get the next reminder

Frequently asked questions

How often does the duct need this?

Once a year is the baseline for an average household on a short, straight run. Move to every 6 months if you dry more than 6 loads a week, own shedding pets, or have a duct longer than about 25 feet. Manufacturers generally cap a rigid run near 25 feet and subtract roughly 5 feet for each 90-degree elbow, so a twisting duct behaves like a much longer one. The full interval list sits on the dryer vent maintenance checklist.

How do I know the vent is clogged before it gets bad?

Four tells. Towels or jeans need a second cycle. The dryer cabinet and the laundry room feel hot and humid after a load. There is a burning or scorched smell. And the outside hood flapper barely lifts while the dryer runs, which is the check that takes 10 seconds and settles it. Lint appearing around the door seal is another sign air is backing up rather than leaving. Start with why a dryer vent is not blowing outside.

I clean the lint screen every load. Is that enough?

No, and that gap is exactly where the fire statistic comes from. The screen catches the visible fluff, but fine fibers pass right through the mesh and settle in the duct where the air slows at every bend. Fabric softener sheets also glaze the screen with an invisible film over time, so rinse the screen under hot water with a brush every few months. The screen is a per-load habit; the duct is an annual job, and neither substitutes for the other.

What does skipping this actually cost?

Start with energy: a restricted duct can double cycle time, so every load runs twice as long for the same dry clothes. Then the equipment. Heating elements cook themselves out at $150–350 installed, thermal fuses blow at $100–200, and a dryer that keeps overheating shortens its own 10 to 13 year life. Set against a $25 brush kit and one hour a year, the arithmetic is not close. The escalation ladder is on the cost of dryer vent neglect.

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