You run a normal load, the cycle ends, and the clothes are still damp. So you run it again. If your dryer is taking too long to dry, or it routinely needs two cycles for a load that used to take one, the dryer itself is often fine. The usual culprit is the vent: the duct that carries hot, wet air out of your home. And with a Toronto winter on the way, now is the best time to sort it out, because snow and ice add a whole new way for that vent to get blocked.
This guide walks you through the signs of a restricted vent, a simple 30-second airflow test, the checks you can do yourself, and how to tell when the problem is actually a heating or sensor fault that needs a technician.
Why the Vent Matters So Much
A dryer works by heating air, pushing it through your tumbling clothes to pick up moisture, and then blowing that warm, wet air outside. If the air can’t get out fast enough, the moisture stays in the drum, the clothes stay damp, and the cycle drags on. The dryer also runs hotter than it should, which wears out parts and can trip its safety devices.
That’s why a slow dryer is worth taking seriously. The City of Toronto’s clothes dryer fire safety page names lack of maintenance as a leading cause of dryer fires and recommends regularly removing lint from the ducts and exhaust vent, not just the lint screen.
Signs Your Dryer Vent Is Restricted
You don’t need tools to spot most vent problems. Watch for these:
- Loads take two cycles, or the dryer runs well past its usual time on auto-dry.
- Clothes come out hot but damp, especially thick items like towels and jeans.
- The laundry room feels warm and humid while the dryer runs.
- The top or sides of the dryer feel very hot to the touch.
- A burning or hot-lint smell during or after a cycle.
- Lint collecting around the outside vent hood or behind the dryer.
- The outside flap barely opens, or doesn’t open at all, when the dryer is running.
- A vent warning on the display. Some newer dryers can detect restricted airflow and show a message or code. Check your owner’s manual for what yours means.
If you notice a burning smell or the cabinet is unusually hot, stop using the dryer until the vent has been checked. Don’t leave it running while you’re out or asleep.
The 30-Second Airflow Test at the Outside Flap
This is the quickest way to find out if your vent is the problem.
- Clean the lint screen first so you’re testing the vent, not the filter.
- Start the dryer on a timed heat cycle, empty or with a few damp towels.
- Go outside and find the vent hood. It’s usually a small hood or louvered cover on an outside wall, near the laundry room.
- Hold your hand a few inches in front of it. You should feel a strong, steady stream of warm air and see the flap or louvers pushed open.
- Compare it to what you remember, or to a neighbour’s dryer if you can. A weak trickle of air, or a flap that barely lifts, points to a blockage somewhere between the dryer and the outside.
If the airflow is strong outside but the dryer is still slow, skip ahead to the section on heating and sensor faults.
Lint Screen, Duct and Booster Checks
Unplug the dryer before you pull it away from the wall or touch the duct. If you have a gas dryer, move it gently so you don’t strain or kink the gas line, and leave the gas connection alone.
1. Clean the lint screen properly
Empty it after every load. Every so often, wash it with warm water, a little dish soap and a soft brush. Dryer sheets can leave a waxy film you can’t see that blocks air. A simple test: run water over the screen. If it pools on top instead of passing through, it needs a wash. While it’s out, use a vacuum crevice tool to pull lint from the slot the screen sits in.
2. Check the duct behind the dryer
The short section of duct between the dryer and the wall is where trouble often starts. Look for:
- Sections that are crushed, kinked or squashed flat because the dryer was pushed too close to the wall.
- Long, sagging runs where lint settles in the low spots.
- Loose connections that leak warm, linty air into the room.
Disconnect the duct at the dryer and look inside with a flashlight. If it’s packed with lint, it’s time for a cleaning. A dryer vent brush kit from a hardware store works for short, accessible runs. For long runs, runs through ceilings or walls, or anything you can’t reach both ends of, a professional dryer vent cleaning service is the safer choice.
3. Check the outside hood
Clear lint from the hood and make sure the flap or louvers move freely. Birds and wasps sometimes nest in vent hoods, especially ones that don’t close fully. Never put a screen or mesh over a dryer vent: it traps lint and blocks the airflow you’re trying to restore.
4. If you have a booster fan
Some homes with very long vent runs have an inline booster fan that helps push air outside. If it stops working, airflow drops sharply. Check that it switches on when the dryer runs and that it isn’t clogged with lint. Wiring or replacing a booster fan is a job for a qualified installer.
Foil and Plastic Ducts vs. Rigid Metal
If the duct behind your dryer is white plastic or thin, accordion-style foil, it’s worth replacing. The City of Toronto recommends using rigid or flexible metal venting rather than plastic or foil. Rigid metal has smooth walls that catch less lint and doesn’t crush as easily. Where you need some flexibility to connect the dryer, a semi-rigid metal duct is a common choice.
Keep the run as short and straight as you can, avoid extra bends, and secure joints the way the duct manufacturer recommends. Your dryer’s installation manual lists the maximum vent length for your model, and it gets shorter with every elbow you add. If your setup is longer than that, the dryer will always struggle, no matter how clean the duct is.
Winter in Toronto: Frozen or Snow-Blocked Vent Flaps
Winter adds a problem that many people don’t think about. Warm, wet air leaving the vent can freeze on the flap, and over a few cold days the flap can ice shut. Snow drifts and snowbanks from shovelling can also bury a vent that sits low on the wall.
CBC’s dryer safety guide, citing Toronto Fire Services, advises checking that outside vent flaps aren’t freezing shut. Here’s how to stay ahead of it:
- After a snowfall, check that the vent hood is clear, and don’t pile shovelled snow against that wall.
- During a cold snap, glance at the flap now and then while the dryer runs to make sure it opens.
- If the flap is frozen, turn the dryer off and gently clear the ice by hand. Avoid hammering on the hood, which can crack it or bend the flap.
- If the flap ices up again and again, the hood may be damaged, sagging, or letting moisture pool. That’s worth having looked at before it becomes a recurring blockage.
Condos and Long Vent Runs
Many Toronto condos and newer townhomes have dryers tucked into closets, with vent runs that travel through ceilings to an outside wall far from the laundry. These setups have a few extra quirks:
- You may not be able to reach the whole duct. Lint can build up in sections hidden above a ceiling, so a brush from the dryer end won’t clear it all.
- The exterior vent may be on a balcony or high on the building. In many buildings, the outside portion is the condo corporation’s responsibility, so check with your property manager before arranging any work.
- Closet dryers need make-up air. The City of Toronto notes that a dryer in a closet needs enough incoming air to run properly. Keep louvered doors clear, and don’t stack laundry against them.
- Ventless (condenser or heat pump) dryers are different. They don’t vent outside, but they have their own filters and condenser to clean. A slow ventless dryer usually means those need attention. Check your manual for how to clean them.
When It’s a Heating or Sensor Fault Instead
If the vent is clear, the airflow outside is strong and the lint screen is clean, but the dryer still takes too long, the problem is likely inside the machine. Common causes include:
- Weak or no heat. A failing heating element, thermostat or thermal fuse on an electric dryer, or an igniter or gas valve problem on a gas dryer. On electric dryers, one tripped half of the double-pole breaker can leave the drum turning with no heat. Our guide to a dryer not heating walks through these in detail.
- Moisture sensor problems. Many dryers use metal sensor bars inside the drum to decide when clothes are dry. If the bars are coated with residue from dryer sheets or fabric softener, the dryer can misread the load and end too early or run too long. Wiping them with a little rubbing alcohol on a soft cloth often helps.
- Clothes coming out too wet from the washer. If the washer isn’t spinning or draining fully, the dryer has far more water to remove. If loads are dripping when they come out of the washer, read our post on a washer not draining.
- Overloading. A packed drum doesn’t let air circulate. Try a smaller load before assuming something is broken.
It’s also worth keeping your laundry room tidy in general. Our tips on cleaning a washer lint trap help keep lint from building up on the washer side of the laundry routine too.
When to Call a Pro
Call a technician, and stop using the dryer in the meantime if there’s any sign of overheating, when:
- You smell burning, or the cabinet gets very hot.
- The airflow outside is strong, but drying is still slow. That points to a part inside the dryer.
- The thermal fuse has blown, especially more than once.
- You have a gas dryer and suspect a heating problem. Gas components aren’t a DIY job, and if you ever smell gas, leave the home and call your gas utility from outside.
- The vent run is long, hidden in walls or ceilings, or you can’t reach the outside hood safely.
Quick Recap
- Clean the lint screen and wash it if water doesn’t pass through.
- Do the 30-second airflow test at the outside flap.
- Check the duct behind the dryer for crushing, kinks and lint, and swap plastic or foil for metal.
- Keep the outside flap free of snow and ice all winter.
- If airflow is strong but drying is still slow, it’s likely a heating or sensor fault.
Need Help With a Slow Dryer?
If you’ve cleared the vent and your dryer still takes forever, I-Fix Appliance Repair can find out why. Our technicians diagnose and repair electric and gas dryers across Toronto, North York, Scarborough and Etobicoke, and we’ll tell you straight whether it’s the vent, a part, or something else. Visit our dryer repair page or contact us to book a visit.