How to Clean a Dryer Vent

This is the highest-value hour of maintenance in the house. A restricted duct is the reason dryers take two cycles, the reason heating elements and thermal fuses fail early, and the condition behind clothes-dryer fires. Everything below is ordered so you can work straight through it.

First, Confirm You Need It

Two checks, both free, both worth doing before you buy a brush.

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• The outside test. Run the dryer on high heat and hold a hand at the outside hood. Strong, warm air means the duct is clear. Weak air means it is not
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• The screen test. Take the lint screen out and pour water on it over a sink. Water should run straight through. If it beads and sits, softener film has sealed the mesh, and the machine has been breathing through it for months
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Other signs: clothes needing two cycles, the top of the dryer hot to the touch, a burning smell, or lint visible around the outside hood. Any of those means the duct, not the machine.

What You Need

Step by Step

1. Kill the power, and mind the gas

Unplug an electric dryer, or switch off the breaker if it is hard-wired. On a gas dryer, leave the gas connection alone entirely: you can move the machine gently to reach the duct, but if the flexible gas line is disturbed or you smell gas at any point, stop and get it checked. Cleaning the duct is a homeowner job; gas fittings are not.

2. Pull the machine out and disconnect the hose

Walk the dryer forward far enough to work behind it, without stretching the cord or the gas line. Loosen the clamp at the machine and at the wall, and pull the transition hose off both ends. Look at it in the light: if it is plastic or foil, sagging, crushed or full of lint, replace it rather than cleaning it. This one piece is the most common restriction in the whole system.

3. Brush the duct from the inside

Feed the rotary brush into the wall duct and add rods as you go. Run the drill slowly and in the direction the kit specifies, usually clockwise, so the rods stay screwed together. Push and pull in short strokes rather than forcing it forward. You are dislodging a felted layer, not drilling through it.

4. Do the same from the outside

Go to the termination and repeat from that end. Lint packs hardest at the hood, because that is where the air slows and the flap restricts it. Working from both ends is what separates a proper clean from a token one, and it is why a professional visit takes the time it does.

5. Clean the hood itself

Take the cover off if it comes off, and clear the flap and its hinge. Flaps stick with lint, get painted shut during exterior work and are a favourite nesting site for birds. A flap that does not open freely undoes everything you have just done inside the duct. If the hood has a screen or a mesh guard, remove it: mesh belongs on a soffit, not on a dryer termination, because it traps lint by design.

6. Vacuum both ends and the machine

Vacuum the lint you have loosened at the wall opening and at the hood, then the lint screen housing inside the dryer, which collects a surprising amount that never reaches the duct. Vacuum the floor and the back of the machine while you are there.

7. Reconnect properly

Fit the transition hose with the shortest possible run and the fewest bends, clamped at both ends. Seal joints in rigid duct with foil tape. Do not use screws that protrude into the duct, because they catch lint and build a blockage exactly where you cannot see it. Push the machine back gently, leaving a few inches so the hose is not crushed against the wall.

8. Prove it worked

Run the dryer on high for five minutes and feel the outside hood again. The air should be noticeably stronger than before you started. If it is not, the restriction is somewhere you have not reached, which usually means a long run, a hidden bend or a crushed section inside the wall, and that is the point to call someone with a camera and a longer brush.

How Often

Our Florida-specific guidance is in how often a dryer vent needs cleaning in a humid climate, where damp air and long summers change the intervals.

What a Blocked Duct Costs You

Beyond the time wasted running loads twice, the mechanical damage is real and it shows up in our price book. A restricted duct makes the heat path run hotter than designed, and parts start failing in pairs: a thermal fuse with a failed element behind it, or a burnt terminal block.

Across 136 completed dryer repairs in our own book the median finished job came to $354, with the middle half between $280 and $390 and 79 percent under $400. The top tenth, above $456, is largely machines that have been overheating for months. In other words, an hour with a brush is cheaper than the repair it prevents, and considerably cheaper than the machine it saves. The full breakdown is in the dryer repair cost database.

The Safety Part, Briefly and Without Drama

Lint is fuel. A restricted duct is where lint accumulates and where the air stops carrying heat away. That combination is the mechanism behind clothes-dryer fires, and it is why the maintenance on this page is not optional housekeeping. There is no need to be frightened of a dryer; there is a need to keep the air moving through it.

Three rules that matter more than the rest: never run the machine without the lint screen in place, never vent a dryer into a crawl space or an attic, and never use flexible plastic duct. Our fuller treatment of the risk is in what a clogged dryer vent actually risks.

When to Call Someone Instead

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• You cannot reach the whole run. Long ducts, runs inside walls and roof terminations need longer rods and, sometimes, a camera
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• The airflow is still weak after cleaning. That means a restriction you have not found, a crushed section, or a bird nest in an inaccessible spot
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• The machine is on an upper floor with a vertical run. Gravity works against you, and the termination is often on a roof
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• You have a gas dryer and the connection needs moving, which should be done by someone qualified to work on it
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• There is evidence of overheating: a burnt smell, scorch marks at the terminal block, or a thermal fuse that has already been replaced once
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• The duct is shared or unknown, as in some condo buildings, where what you can see is a small part of the run
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While the Machine Is Pulled Out

You have moved the dryer, which is the hard part of several other jobs. Five minutes more while you are back there is worth taking.

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• Vacuum the floor and the back panel. Lint that escapes the screen settles here and holds heat against the cabinet
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• Look at the cord and the outlet on an electric machine. Discoloured or scorched terminals are a fault in their own right and a reason to stop and call someone
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• Check the machine sits level on all four feet. A dryer that rocks is noisier and harder on its rollers and bearing
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• Look for a build-up of lint inside the lint screen housing, and vacuum it out with the crevice tool
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• Note the duct material and length for next time, so you know whether you are on the annual or twice-yearly schedule
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If you find scorching, a smell of burning, or a duct that has come apart inside the wall cavity, stop there. Those are not maintenance findings; they are reasons to have the installation looked at before the machine runs again.

A blocked vent does not only slow drying — it blows the thermal fuse and kills the machine outright: dryer not turning on.

Frequently Asked Questions