A dryer that slowly takes longer and longer to dry a load is one of the most common appliance complaints, and one of the most important to take seriously. Most of the time the cause is airflow, not the dryer itself. Hot, damp air has to leave the drum and travel through the vent to the outside; when it can’t, clothes stay wet, the dryer runs hotter and lint builds up in places where it can catch fire.
1. A clogged lint screen
Start with the easy one. Clean the lint screen before every load. If you use dryer sheets, the screen can get a waxy film that blocks air even when it looks clean; hold it under running water, and if water beads up instead of passing through, wash it with warm soapy water and a soft brush.
2. A clogged or crushed vent
Lint that gets past the screen collects in the duct behind the dryer and along the vent run to the outside. Thin foil or plastic ducts crush easily when the dryer is pushed back, and long runs with several elbows clog faster. In townhomes and condos, vents often run through walls or up to the roof, which makes them long and hard to clean. Check the outside vent while the dryer runs: you should feel a strong, warm stream of air and see the flap open fully.
The U.S. Fire Administration estimates about 2,900 home clothes dryer fires a year, and failure to clean the dryer is the leading cause. If your dryer is hot to the touch or takes much longer than it used to, stop using it until the vent is cleaned.
3. Too much in the drum
Clothes need room to tumble so air can move through them. A drum packed full of towels or a heavy comforter dries slowly and unevenly. Dry large items on their own and split big loads. Make sure the washer is spinning properly too; if clothes come out of the washer dripping wet, the problem may be a washer that isn’t reaching full spin speed.
4. A heating problem
If the dryer runs but the air is barely warm, the heat source may be failing. On electric dryers, the common causes are a heating element with a break in the coil, a cycling thermostat or a blown thermal fuse; half of the 240-volt double breaker tripping can also cause a dryer to tumble without heat. On gas dryers, a weak igniter or failing gas valve coils are typical. A thermal fuse usually blows because of poor airflow, so replacing it without clearing the vent just sets up the next failure.
| What you notice | Likely cause |
|---|---|
| Takes longer every month | Lint building up in the vent |
| Dryer and laundry room very hot | Restricted airflow |
| Tumbles with no heat at all | Element, thermal fuse, igniter or a tripped breaker half |
| Heat comes and goes | Cycling thermostat or gas valve coils |
| Clothes come out of the washer very wet | Washer not spinning fully |
What about heat pump and ventless dryers?
Heat pump dryers, which are becoming more common in Bay Area homes moving away from gas, don’t vent outside. They dry at lower temperatures and normally take longer than vented dryers. They still need their lint filters cleaned every load and their condenser or secondary filter cleaned as the manual describes. If a heat pump dryer suddenly gets much slower, those filters are the first thing to check.
When to call a technician
Call if the dryer tumbles with no heat, stops mid-cycle, smells hot, squeals or thumps, or is still slow after you’ve cleaned the lint screen and checked the outside vent. A technician can test the heating parts, check the airflow and tell you whether the vent needs professional cleaning. Our dryer repair guide covers the common fixes, and if the washer is part of the problem, see washer repair. For everything else, visit our appliance repair help page.