Your dryer runs the full cycle. You open the door. Clothes are warm — but still damp. So you run it again. That second cycle is a warning. Not an inconvenience.
Here's what's actually happening.
90% of the Time: It's the Vent
The lint trap is the part you see. It's not the problem.
Behind the dryer is a flexible duct. That duct runs through the wall and terminates outside — usually with a flap vent near the foundation or roofline. Every load pushes hot, humid air through that duct. Lint, dust, and moisture accumulate on the duct walls over months and years.
Eventually, airflow drops. The dryer can't exhaust fast enough. Heat and humidity back up inside the drum. Clothes don't dry — they just get warm.
Signs it's a venting problem:
- Clothes are warm but damp after a full cycle
- The laundry room feels humid while the dryer runs
- The exterior vent flap barely moves during operation
- It takes two cycles for thick items like towels or jeans
How to check it yourself:
Go outside and find the vent termination while the dryer is running. The flap should be open and you should feel a strong, steady stream of warm air. Weak airflow or no movement at all — that's a clogged duct.
Pull the dryer away from the wall. Disconnect the flexible duct from the back of the machine. If it's crinkled, kinked, or more than five feet long with multiple bends, airflow is already compromised before it even reaches the wall.
When to Call a Vent Cleaner (Not a Repair Tech)
If the duct is the problem, you don't need an appliance technician. You need a vent cleaning service.
A professional dryer vent cleaner uses a rotary brush and high-powered vacuum to clear the full duct run — including sections inside the wall you can't reach. They'll also inspect the exterior termination and replace the flexible duct if it's damaged.
Call a vent cleaner if:
- It's been more than a year since the duct was last cleaned
- You can see lint buildup at the exterior vent
- The flexible section behind the dryer is torn, crushed, or accordion-kinked
- Your duct run is longer than eight feet or has multiple 90-degree bends
This is maintenance, not repair. Most vent cleanings take under an hour and cost far less than a service call.
10% of the Time: It's the Moisture Sensor
Some loads take two cycles even after the duct is clean. That points to the moisture sensor.
Modern dryers don't run on a timer alone. They use two metal sensor bars inside the drum — usually near the lint trap opening — to detect residual moisture in the fabric. When the clothes are dry, the sensor tells the control board to end the cycle.
If the sensor bars are coated with dryer sheet residue or mineral buildup, they stop reading correctly. The dryer thinks clothes are dry before they actually are. Cycle ends early. You restart it.
How to test the sensor:
Run a normal load. When the cycle ends early, reach in and feel the clothes. If they're only slightly damp — not wet — the sensor is likely the culprit. If they're genuinely wet and cold, the problem is venting or heat.
How to clean the sensor:
Locate the two thin metal bars inside the drum. Wipe them down with a cotton ball and rubbing alcohol. Let them dry completely before running another load. This takes two minutes and costs nothing.
If cleaning doesn't fix it, the sensor has failed electrically and needs replacement. That's a repair tech call.
The Decision Tree
| Symptom | Likely Cause | Who to Call | |---|---|---| | Warm but damp clothes, humid laundry room | Clogged vent duct | Vent cleaning service | | Cycle ends early, clothes slightly damp | Dirty or failed moisture sensor | DIY clean first, then repair tech | | No heat at all | Heating element or thermal fuse | Repair tech | | Clothes wet and cold after full cycle | Severe duct blockage | Vent cleaning service — urgent |
One More Thing
A clogged dryer duct is a fire hazard — not just an efficiency problem. Lint is combustible. Restricted airflow traps heat. The National Fire Protection Association consistently lists clogged vents as the leading cause of dryer fires.
If your dryer is running two cycles per load, don't keep running it and hoping it resolves. Check the vent first. Clean the sensor second. If neither fixes it, call a tech.
The machine is usually fine. The path out isn't.