How to clean a dryer vent

The lint screen catches most of the lint, but not all of it. The rest builds up in the duct that carries hot, damp air outside, where it slows the dryer and can catch fire. Cleaning the duct is a once-a-year job with a cheap brush kit.

Written by the developer of Gable · Published 13 September 2026

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Why it matters

Lint is fine, dry and very flammable, and the duct is where it meets the dryer’s heat. US fire statistics name failure to clean as the leading factor in home clothes dryer fires. A clogged duct also traps moisture, so every load runs longer. The dryer costs more to run and wears out faster.

In Gable’s library: “A $20 brush vs a house fire and a dryer that costs twice as much to run.”

Signs your vent needs cleaning

• Towels or jeans need a second cycle to dry.
• The top of the dryer, or the clothes, feel unusually hot.
• A musty or burning smell while it runs.
• The flap on the outside wall barely lifts, or doesn’t open at all, while the dryer is running.
• Lint collecting around the outside vent, or behind the dryer.

Any of these is a reason to clean it now rather than wait for the yearly reminder.

How often

At least once a year for a typical household. Clean it more often if you dry several loads a day, have pets, or have a long duct with several bends. Long runs collect lint faster and push air out more weakly.

What you need

• A dryer vent brush kit: a round brush on flexible rods that screw together, sold at hardware stores. Some attach to a drill.
• A vacuum with a hose attachment.
• Aluminium foil tape (real metal tape, not cloth “duct tape”) or a duct clamp.
• A screwdriver, if your duct connects with clamps.

Step by step

1. Unplug the dryer. On a gas dryer, also turn off its gas valve. Move it gently so you don’t kink or strain the gas line. If you aren’t comfortable around a gas connection, this is a job for a pro.
2. Pull the dryer out far enough to reach the duct.
3. Disconnect the duct from the back of the dryer and from the wall outlet, loosening the clamps or peeling off the old tape.
4. Brush the duct from the inside end. Push the brush in while turning it in the direction that keeps the rods screwed together, and pull the lint back out. Add rod sections until you reach the outside.
5. Go outside and do the same from the exterior end, after removing or opening the vent hood. Pull out any lint, nests or debris around the flap.
6. Vacuum the dryer’s exhaust outlet, the lint screen slot, and the floor behind the machine.
7. Reconnect the duct with foil tape or clamps. Don’t use screws, because they stick into the duct and catch lint.
8. Test it. Run the dryer on high and check outside: the flap should open and you should feel strong, warm airflow.

Check what the duct is made of

While the dryer is pulled out, look at the connector between the dryer and the wall. White vinyl or thin foil accordion hose sags, traps lint and can melt or burn. Dryer manufacturers and building codes generally call for a metal duct: rigid, or semi-rigid aluminium for the short connector. It should be as short and straight as the room allows, without a crushed section behind the machine. Replacing a plastic connector costs little and is worth doing the same day.

When to call a professional

• The duct runs a long way inside walls or ceilings, or exits through the roof.
• The outside vent is on a second storey you can’t reach safely.
• The brush meets a blockage it can’t clear, or you find a bird’s nest deep inside.
• The dryer is gas and you don’t want to move it yourself.

A dryer vent cleaning service uses a rotary brush and an air blower. It’s a short, inexpensive visit, and many will also inspect the duct.

Put the dryer vent on a schedule

Gable adds the yearly dryer vent clean to every house plan, reminds you when it’s due, and logs when it was done. It sits alongside the smoke alarm tests and the rest of your safety jobs. No account; nothing leaves your phone.