My Dryer Is Taking Too Long to Dry Clothes: The Vent May Be to Blame

A dryer that needs two cycles for the same load almost never suffers from an internal mechanical problem — in the vast majority of cases, the cause is an exhaust duct clogged with lint, an invisible problem that develops gradually without ever showing up as an obvious breakdown.

How to recognize the problem

• Clothes still come out damp after a full cycle, consistently forcing a second run
• The dryer becomes unusually hot to the touch during the cycle
• A burning smell comes from the appliance during or after drying
• The room where the dryer sits gets hotter and more humid than usual during operation
• The exterior vent flap barely moves while the dryer is running — a direct sign very little air is actually escaping

Why it happens

Every drying cycle releases lint that inevitably escapes the filter, no matter its quality. Over time, this residue gradually builds up in the duct, particularly at elbows and along horizontal runs where airflow naturally slows. A duct that's only 50% blocked can easily double the drying time needed — a gradual change often wrongly blamed on the appliance's age rather than the real cause.

It's not just about convenience

A clogged duct forces the motor and heating element to work longer for every load, wearing the appliance out prematurely and increasing electricity use for a worse result. More importantly: a blocked duct is one of the leading causes of dryer-related house fires — see our full article on that risk to understand the exact mechanism.

A quick test you can do yourself

Go outside and watch the exterior exhaust cap while the dryer runs at full cycle. Healthy airflow makes the flap swing open wide and visibly; a flap that barely moves, even at full power, almost always confirms a significant blockage somewhere along the run.

Recommended cleaning frequency

A professional duct cleaning once a year is recommended for standard residential use, and more often if the duct is long, has several elbows, or you regularly dry large loads — bedding, towels, bulky items that generate more lint per cycle.

What you can check yourself, and its limits

Clean the lint filter before every cycle — essential, but not enough long-term, since some lint always slips through no matter how diligent the cleaning. Full duct cleaning requires specialized equipment (rotary brush, industrial vacuum) to reach the entire run, often well beyond what an arm or household vacuum can cover.