Why is no air coming out my dryer vent outside?
Updated August 2026
Little or no air at the outside vent hood almost always means the duct run is packed with lint and the dryer's blower can no longer push exhaust the full 15 to 25 feet to the exterior. Clean the entire run first, from the dryer to the hood: it fixes weak airflow more often than any part swap and costs a $20 to $40 brush kit, or $100 to $200 for a pro. If a clean duct, a working flapper, and an uncrushed hose still leave you with a faint trickle, work down the causes below, roughly in order of how common each one is.
Safety first: weak or no air at the exterior hood is the clearest early warning of the lint buildup behind most home dryer fires. Never vent a dryer through flammable vinyl accordion duct, never seal joints with sheet-metal screws (their tips snag lint inside the pipe), and never let the run terminate in an attic, crawlspace, or wall cavity. Clean the whole run, not just the trap, and if you see scorch marks or smell burning, stop using the dryer until it is inspected. What that neglect finally costs is laid out in our dryer vent neglect guide.
Causes, most likely first
| Cause | How likely | The fix | Typical cost |
|---|---|---|---|
| Lint-clogged vent duct or hood | Most common | Disconnect the duct and brush the full run from both ends, then vacuum and reconnect with foil tape. Confirm strong airflow at the hood afterward. | $100–200 pro, or a $20–40 brush kit |
| Stuck or lint-packed exterior flapper | Common | Free the louvered damper, clear the caked lint, or replace the vent hood so it can open fully under airflow. | $0–60 |
| Crushed or kinked flex duct behind the dryer | Common | Reshape or replace the hose and keep the dryer a few inches off the wall so the duct is not pinched flat. | $15–40 hose |
| Pest nest in the duct or hood | Occasional | Clear the bird or rodent nest and fit a proper vented cover with a damper, not a fine screen that re-clogs with lint. | $60–200 |
| Disconnected duct venting inside the wall | Occasional | Find the separated joint dumping lint into the cavity, reconnect it, and seal with foil tape rather than sheet-metal screws. | $50–250 |
| Cracked or clogged dryer blower wheel | Rare | If the duct is clear and airflow is still weak, the dryer's own blower wheel may be failing and needs service. | $150–400 |
Check these first
- Run the dryer on a timed or air-fluff cycle and hold your hand at the outside hood: you should feel a strong, steady push, not a faint trickle.
- Lift the exterior flapper by hand and clear packed lint from the louvers so the damper can swing fully open.
- Pull the dryer a foot off the wall and check the flex duct behind it for a hard kink or a crushed section.
- Disconnect the duct at the dryer and see how much lint falls out; a full handful means the run is badly overdue.
- Feel the clothes and the cabinet at the end of a cycle: a hot machine plus damp laundry points straight at a restricted vent.
- Trace the duct route if you can and look for a joint that has pulled apart or a hood packed with debris or a nest.
Prevent it next time
Weak airflow is a maintenance failure you can schedule away. Empty the lint trap every single load, and clean the full duct run at least once a year, or every six months for a long or upstairs run. When the flex hose behind the dryer is crushed, kinked, or the old vinyl accordion type, swap it for rigid or semi-rigid metal on the recommended schedule. Our dryer vent maintenance checklist covers the trap, the duct, and the exterior hood in one pass, and the lint trap explainer shows why the screen alone is never enough.
When to call a pro
Call a pro when the duct travels through a wall, ceiling, or roof, when the run is long with several elbows, or when you find a joint that has pulled apart and is dumping lint into the structure. A standard vent cleaning runs $100–200, and longer or rooftop runs $200–350. Also call if the duct is spotless but airflow is still weak, since the dryer's own blower wheel may be cracked, a $150–400 repair. A clogged run left alone eventually shows up as clothes that never dry in one cycle and, worse, a fire risk.
Most of the causes above are maintenance problems wearing a disguise. OnOtto keeps the boring prevention on schedule so the 2 a.m. version doesn't happen.
Stop chasing symptoms, free for 30 daysFrequently asked questions
How can I tell if my dryer vent is clogged?
Four signs point to a clogged run. Clothes come out damp after a full cycle and need a second round. The dryer cabinet and the laundry room feel unusually hot. You feel little or no air at the outside hood while the dryer is running. And a burning or musty smell shows up mid-cycle. Any one of these means lint is choking the duct; two or more means clean the full run now, before the restriction turns into a fire risk rather than a slow-drying nuisance.
Can I clean a dryer vent myself?
Usually yes, for a straight run of 15 to 25 feet. Unplug the dryer, pull it out, disconnect the duct, and run a rotating lint-brush kit ($20 to $40) through from both the dryer end and the outside hood. Vacuum the debris, reconnect with foil tape rather than screws, and confirm strong airflow at the hood. Call a pro when the duct climbs through a wall or ceiling, exits at the roof, or runs longer than about 25 feet with several elbows.
How often should a dryer vent be cleaned?
At least once a year for a typical household, and every six months if you dry daily, have a long or twisting duct, run a large family's laundry, or own shedding pets. A ground-floor exit that runs a few straight feet clogs slowly; an upstairs laundry that vents through the roof clogs fast. If clothes have started taking two cycles to dry, do not wait for the calendar. Our dryer vent maintenance checklist lays out the full routine.
Is it safe to run the dryer when no air comes out the vent?
No, not until you find and clear the blockage. With nowhere to exhaust, hot, lint-laden air backs up inside the cabinet and around the heating element, which is exactly the condition behind most home dryer fires. It also traps moisture, so clothes stay damp and the machine runs far longer than it should, driving up both the electric bill and the wear. Shut the dryer off, clean the full duct, and confirm strong airflow at the outside hood before your next load.