What are the signs your dryer vent is clogged?

The most common signs of a clogged dryer vent are clothes that are still damp after a full cycle, loads that take much longer than they used to, a dryer or laundry room that runs hotter than usual, a burning or musty smell, and an outside vent flap that barely opens. If you notice any of these, have the vent checked. If you smell burning, stop using the dryer until it's been looked at.

I'm David Sherman, owner of Dryer Dryer LLC and a Certified Dryer Exhaust Technician (C-DET), and I'm on every call. A clogged vent creeps up, and people get used to running the dryer twice. Here's what to watch for.

The signs, and what they tell you

Loads take longer, or clothes come out damp. A load that used to take 40 minutes now takes 60 to 90. When the vent is restricted, the moist air has nowhere to go, so the dryer just keeps tumbling wet clothes.

The dryer, the clothes or the laundry room feel unusually hot or humid. Heat that should leave through the vent is building up inside the machine and the room. Lint around the dryer or the outside vent is another clue.

A burning or musty smell while the dryer runs. Burning can mean lint is getting too hot somewhere in the dryer or vent. Musty can mean moisture is sitting in the vent. Either way, get it checked. With burning, stop using the dryer first.

The outside flap barely opens, or you feel little air. Go outside while the dryer is running. You should feel a good, steady push of air and see the flap open. On Cape, wind and salt air wear out vent caps and flaps, and a flap that sticks shut traps lint and moisture.

The dryer shuts itself off partway through a cycle. A dryer that's running too hot can trip its safety thermostat or blow its thermal fuse. A blown thermal fuse is the most common reason a dryer suddenly stops heating.

Quick checks you can do yourself

Clean the lint screen. If you use dryer sheets, run water over the screen. If the water beads up instead of passing through, wash it with warm soapy water and a soft brush and let it dry fully.
Look behind the dryer. Is the hose kinked, crushed or pulled loose?
Check the outside vent while the dryer runs. Strong airflow means the vent is probably fine. Weak airflow points to the vent.

If airflow outside is strong and the dryer still won't heat, the problem is more likely the dryer itself, and an appliance technician should look at it. My inspection measures airflow, so it can tell you which one it is.

Things that make clogs more likely

White plastic or thin foil "accordion" duct. It traps lint, crushes easily and doesn't meet code. The run inside the walls should be rigid, smooth metal pipe.
Bird nests, especially in vents that sit unused over the winter.
A screen on the outside vent. Screens at the duct termination aren't allowed under the Massachusetts Residential Code, section M1502.3, because they clog with lint.

A note on gas dryers

With a gas dryer, a blocked, crushed or disconnected vent can let carbon monoxide back up into the house, so keep working CO alarms in the home. Electric dryers don't make carbon monoxide, but a blocked vent is still a fire risk.

Frequently asked questions

What are the signs of a clogged dryer vent?

Clothes still damp after a full cycle, loads taking much longer, a dryer or laundry room that's hotter than usual, a burning or musty smell, lint around the dryer or the outside vent, an outside flap that barely opens, and a dryer that shuts off mid-cycle.

What should I do if I smell burning when the dryer runs?

Stop using the dryer right away and have the vent checked before you run it again.

How can I tell if it's the vent or the dryer?

Check the airflow at the outside vent while the dryer runs. Weak airflow usually means the vent. If airflow is strong and the dryer still won't heat, the problem is probably in the dryer, and an appliance technician should look at it.

Why does my dryer keep shutting off or stop heating?

A blocked vent makes the dryer run hot, which can trip its safety thermostat or blow its thermal fuse. A blown thermal fuse is the most common reason a dryer suddenly stops heating.

Can a clogged dryer vent cause carbon monoxide?

With a gas dryer, yes. A blocked, crushed or disconnected vent can let carbon monoxide back up into the house. Electric dryers don't produce carbon monoxide.

How much does it cost to fix a clogged dryer vent?

A dryer vent cleaning with Dryer Dryer LLC is a $199 flat rate, including the inspection, cleaning inside the dryer, a full vent cleaning, and a digital report with airflow numbers and before-and-after photos. Repairs or re-routes are quoted after the inspection.

Get it checked

If any of these signs sound familiar, let's take a look. I'm on every call, from the first phone call to the airflow reading at the end.

Book online (online booking is for dryer vent cleanings only)
Call (508) 225-5846 if you're not sure whether it's the vent or the dryer
Email: clean@dryerdryer.com