Clean the Lint Filter, Every Load
The simplest cause is also the most common. Clean the lint filter before or after every load, and check that lint has not built up in the filter housing. A clogged filter restricts airflow, so hot air cannot carry moisture away, and drying takes longer. If the filter looks filmed over, wash it with warm soapy water, rinse it, and let it dry fully before putting it back.
Also check the outside vent cap. If you cannot feel warm air coming out while the dryer runs, or lint is packed around the cap, airflow is restricted somewhere in the vent run.
The Vent Run Matters More Than Most People Think
Lint builds up inside the vent run over time, especially in long runs and runs with bends. A crushed flexible vent behind the dryer, a disconnected section, or a long route to the outside can all slow drying. Vent restriction also lets the dryer run hotter, which is a fire risk, and can trip thermal safety parts.
You can check that the vent behind the dryer is not crushed or kinked, and that the outside cap opens freely. Deep vent cleaning, and any work inside the dryer, is best left to a technician, because a brush can push lint deeper or disconnect a section you cannot see. See our dryer vent cleaning page for what cleaning includes.
Load Size and Settings
Overloading the drum stops clothes from tumbling freely, so hot air cannot reach them evenly. Very large, heavy loads, especially towels and bedding, also take longer. Try smaller loads, and make sure the washer has spun the clothes well: clothes that come out of the washer soaking wet take far longer to dry.
Check that you are using a heat setting that matches the load, and that the moisture sensor, if your dryer has one, is not coated with residue. A sensor coated with fabric-softener residue can misread dampness and end cycles early or late.
When It Is a Heating Fault
If the vent is clear and loads are reasonable, a heating part may have failed: a heating element, thermostat, thermal fuse, or, on a gas dryer, an igniter or gas valve. A dryer that tumbles but produces no heat at all, or only lukewarm air, needs diagnosis before parts are replaced.
Stop using the dryer and unplug it if you smell burning or see scorching. Do not keep running it to see if it improves. Call us and tell us whether the dryer heats at all, whether it stops mid-cycle, and whether the vent has ever been cleaned. See our dryer repair page for what a visit includes.