Dryer Takes Too Long to Dry? Here's Why.

A dryer doesn't just heat clothes dry — it moves hot air through the drum, picks up moisture, and exhausts that humid air outside. If the exhaust path is even partially restricted, moisture-laden air can't escape fast enough, drying time doubles or triples, and the dryer runs much hotter than it should.

The vent restriction can be anywhere: the lint trap (common), the flex duct behind the dryer (often kinked), the rigid duct run inside the wall (gradually accumulates lint over years), or the exterior vent termination (flap stuck shut, bird nest, or mesh screen clogged with lint).

LG dryers quantify this directly with their flow-sense system: a d80 code means 80% restricted, d90 means 90%, d95 means nearly completely blocked. See the full guide:

Clean the lint screen before every load — this is not optional. A clogged lint screen forces every cubic foot of exhaust air through a restricted opening and can alone add 20–30 minutes to a drying cycle. If your lint screen has a waxy film (from dryer sheet residue), wash it with warm soapy water and a soft brush, rinse thoroughly, and let it dry completely before reinstalling.

Also check inside the lint trap housing with a long, flexible brush — lint accumulates in the housing below the screen and is often missed.

Pull the dryer away from the wall and inspect the flex duct (the 4-inch accordion-style hose connecting the dryer to the wall). It should be straight, or as close to straight as possible, with no kinks. A kinked flex duct can cut airflow by 50% or more. The flex section should also be as short as possible — ideally under 6 feet.

For the full duct run inside the wall, the maximum allowable equivalent length (per most dryer manufacturers) is 25 feet of straight 4-inch rigid duct, with reductions for each elbow (a 90° elbow equals 5 feet of equivalent length). Many older homes have duct runs that exceed this — especially in townhouses and condos where the dryer is interior and the exhaust run is long.

Check the exterior termination. The flap on the exterior vent cap should open freely when the dryer is running. Reach back there with your hand — you should feel a strong airflow. Little or no airflow at the exterior with a running dryer means there's a serious blockage in the run.

If airflow is verified clear and the dryer still runs slow, the next suspect is the thermistor or cycling thermostat. These components tell the control board how hot the drum air is. A failing thermistor that reads artificially high will cause the control board to reduce heat output prematurely — the dryer runs warm but not hot enough to dry efficiently.

On LG and Samsung, a thermistor reading even slightly out of spec will cause long dry times well before throwing a formal error code. On Whirlpool/Maytag platforms, a weak cycling thermostat produces the same symptom — the dryer cycles off heat too early and runs lukewarm.

Modern dryers use moisture sensor bars — two metal strips inside the drum — to detect when the load is dry and end the cycle. If these bars are coated with fabric softener or dryer sheet residue, they read 'dry' before the load actually is, ending the cycle early. Clothes come out still damp.

Clean the bars with a little rubbing alcohol on a soft cloth. If cleaning doesn't resolve early-shutoff behavior, the bars may need replacement. Samsung dryers are particularly prone to this — it's one of the most common Samsung-specific complaints.

If your dryer is more than 5 years old, has never had the full duct run professionally cleaned, or if your duct run is long (over 15 feet) or has multiple elbows, a professional vent cleaning is money well spent. Lint accumulates inside rigid duct walls over years and no amount of exterior cap cleaning addresses it.

Warning signs that warrant immediate vent inspection: clothes are hot but damp at cycle end, the laundry room smells musty after a cycle, the dryer exterior gets unusually hot, or you've had a thermal fuse fail more than once. See the full safety guide: