What to know
If you smell burning, stop the load
A burning or scorched smell while the dryer is running is the one symptom on this page that is not a maintenance matter. Stop the cycle, and leave the appliance off until somebody has looked at it — do not start another load to see whether the smell comes back. Lint is fine, dry fabric fibre packed into a hot, restricted duct, and the point of stopping is that you cannot tell from the laundry room how far along the problem is. If you see smoke or scorching, get out and call 911 from outside.
Why it clogs when other ducts do not
Most ducts in a house move air that happens to carry dust. A dryer vent moves air that is deliberately full of fabric fibre, warm and slightly damp, through a duct that often has bends in it.
The lint screen catches the coarse material. The fine stuff goes down the vent, and it sticks, particularly at elbows and anywhere the run sags.
What you will notice first
- Loads taking noticeably longer, or needing a second cycle to finish.
- Clothes coming out hotter than usual at the end of a cycle.
- The laundry room feeling humid or warm while the dryer runs.
- Little or no air coming out of the exterior vent hood with the dryer going.
- Lint appearing around the vent hood outside.
The two-cycle problem is the one that gets attention, because it doubles the running time of the appliance for the same laundry. It is also the symptom most worth being careful about, because a vent is not the only thing that causes it — a failed heating element, thermostat or moisture sensor will do the same, so will a washer that is not spinning clothes dry enough, and so will an overloaded drum or the wrong cycle. Check the easy thing first: with the dryer running, go outside and feel whether the hood is pushing a strong flow of warm air. If it is, the restriction is not the problem and the appliance is worth having looked at before anybody cleans a duct. We would rather tell you that than sell you the wrong service.
What makes a run worse than average
- Length. A dryer on an interior wall with a long run to the outside clogs faster than one venting straight through.
- Bends. Every elbow is somewhere lint can catch and build.
- Ridged flexible ducting, whose corrugations hold material that a smooth metal duct would pass.
- A crushed section behind the appliance, which is very common where the dryer sits close to the wall.
- A vent hood flap that has stopped opening fully.
What you can do yourself
Clean the lint screen every load, and wash it in warm water once in a while — fabric softener leaves a film that you can feel but not see, and it restricts the screen more than the lint does.
Pull the dryer out a couple of times a year and look at the duct behind it. That short section is where crushing happens, and it is the part you can actually inspect. If it is rigid or semi-rigid metal, straightening a kink is a reasonable job. White vinyl or plastic ducting is a different matter: it is not permitted behind a dryer, and it should be replaced rather than repaired. The foil-and-wire flexible type is worth looking at properly rather than assuming — it is acceptable when it carries a listing as a dryer transition duct and is installed within the manufacturer's limits on length and concealment, and not acceptable when it is an unlisted product or run in a way those limits rule out. The label tells you which you have. Whatever the material, match a replacement to the dryer manufacturer's instructions and your local code, and check the hood outside opens properly while the dryer runs.
Where the limit is
A vacuum and a brush will reach the first few feet. The rest of the run — the part with the bends, which is where the material actually collects — needs equipment that can work the length of the duct and pull the debris out rather than push it along.
If the run goes up through a wall or across a ceiling, that is beyond what a homeowner can sensibly do from either end.
What we would do
Clear the full run rather than the accessible ends, check the hood is opening and closing as it should, and tell you if the ducting itself is the problem. Foil ducting that has been crushed behind an appliance for years will clog again in months whatever anybody removes from it.
If the honest answer is that the run needs replacing rather than cleaning, you should hear that before you pay for cleaning it.