A dryer that takes noticeably longer than it used to is almost always struggling to move air, not struggling to make heat. The lint trap, the vent duct, and the exterior vent flap between them account for most cases — and rising dry times are the earliest, cheapest warning you get before the same restriction causes a blown thermal fuse or worse.
Why this is the warning worth acting on
Long dry times sit at the start of a predictable chain: restricted airflow makes cycles longer, the trapped heat makes the cabinet run hotter, and eventually the thermal fuse blows and the dryer stops heating entirely. Acting at the long-dry-times stage means clearing a vent; acting after the fuse has blown means clearing the vent and replacing a part. The full chain is covered in our dryer not heating guide, but catching it here is the cheap exit.
Common causes
| Cause | How likely | Typical sign |
|---|---|---|
| Lint trap film reducing airflow | Very common | Trap looks clean but water pools on the mesh instead of draining through |
| Vent duct partially blocked with lint | Very common | Gradual worsening over months; hot cabinet |
| Exterior vent flap stuck or blocked | Common | Flap does not open visibly while the dryer runs |
| Crushed or kinked duct behind the dryer | Common | Started after the dryer was moved or pushed back |
| Overloaded drum | Common | Only slow on big loads; small loads dry normally |
| Washer leaving clothes too wet | Occasional | Spin cycle issue upstream — clothes enter the dryer wetter than before |
| Failing moisture sensor | Occasional | Auto-dry cycles run forever but timed cycles behave normally |
| Heating element partially failed | Occasional | Air noticeably cooler than it used to be |
How to work through it
- Wash the lint screen, not just clear it
A film of fabric softener residue builds up invisibly on the mesh and restricts airflow even when the trap looks clean. Wash it with warm soapy water, rinse, and let it dry fully. Test: run water over the screen — if it pools instead of flowing through, the film is the problem.
- Clean the full vent duct
Disconnect the duct from the back of the machine and clear it end to end with a vent brush. Our dryer vent cleaning guide covers the full process including the exterior termination. This is the highest-value step on this list.
- Watch the exterior flap while the dryer runs
Go outside with the dryer running. The flap should be blown visibly open with a steady stream of warm, moist air. A flap barely moving means the airflow is being lost somewhere before it gets there.
- Check the duct behind the machine
A dryer pushed hard against the wall crushes flexible duct — a very common cause after cleaning behind the machine or moving it. Pull it forward and check the duct holds its shape along the full run.
- Confirm the washer is spinning properly
If clothes come out of the washing machine wetter than they used to, the dryer is being asked to do more work and looks slow through no fault of its own. Our washing machine not spinning guide covers that side.
- Try a smaller load as a test
Run a half-size load and time it. Normal speed on small loads with slow big loads points at overloading rather than a machine fault.
Load habits that mimic a fault
Air has to circulate between items to carry moisture away. A drum packed to the top dries slowly and unevenly no matter how healthy the machine is. As a rule of thumb, the drum should be no more than about three-quarters full, and heavy items like towels dry markedly faster as two small loads than one large one.
When to call for a repair
Call an engineer if dry times remain long after a full vent clean with confirmed strong airflow at the exterior flap, if the air feels cooler than it used to (a partially failed element), or if auto-dry cycles specifically never finish while timed cycles behave — that points at the moisture sensor rather than airflow.
Stop and call a qualified appliance technician or electrician if you find scorched or melted wiring, smell burning, see water that has reached electrical components, or if the fault returns immediately after a repair. Never bypass a safety device — thermal fuses, door interlocks and flood switches fail for a reason, and defeating one converts a broken appliance into a fire or flood risk.
