What restriction actually does
A dryer is designed around a certain amount of airflow out of the back of the machine. Lint narrows the duct, and every foot of duct, every elbow, and every sag makes it harder for the machine to push air out.
When that happens the machine cannot exhaust heat and moisture efficiently, so cycles get longer and both the machine and the duct run hotter. Lint is combustible and the duct is where it collects. That is why this is a safety item and not just a laundry annoyance.
The two failure points we find most
First, the transition hose behind the machine. Pushing the dryer back against the wall crushes it, kinks it, or pulls it off the connection. Flexible foil accordion hose is the worst version, because the ridges catch lint and it collapses easily. A rigid or semi rigid metal transition, kept short with a gentle bend, solves it.
Second, the long attic run. Two story Houston homes often route the duct up and across the attic to a roof or gable termination. Those runs sag between supports, and sags collect lint and condensed moisture. We also regularly find screws driven through the duct at joints, and every screw point inside a duct is a lint catcher.
Vents that terminate in the wrong place
A dryer exhausts warm, moisture laden air, and it has to go outside. We find ducts terminating in the attic, into a soffit where the air gets pulled straight back through the vents, and occasionally into a crawlspace or a wall cavity.
In a climate where humidity is already the main comfort problem, dumping a dryer's worth of moisture into your attic every day raises attic humidity, wets insulation, and works against everything else you have done. If we find one, we tell you, and we can correct the termination.
How we clean it and how we verify it
We clean from both ends, brushing and vacuuming from the machine connection and the exterior termination, so lint comes out rather than getting pushed further along and packed into a bend.
Then we check the exterior hood. The flap has to open freely under airflow, and the screens some hoods come with are lint traps that should not be there. Birds nesting in a hood is a regular find here. We reconnect with a clamp rather than a screw through the duct, then confirm airflow at the termination with the dryer running.
What we check on a dryer vent
- Transition hoseMaterial, length, and whether it is crushed or kinked behind the machine.
- Duct material and lengthRigid versus flexible, total run length, and the number of elbows.
- Fasteners inside the ductScrews through joints that snag lint and build restriction.
- Sags and low spotsUnsupported runs where lint and condensation collect.
- Exterior hood and flapWhether the damper opens freely or a screen or nest is blocking it.
- Termination locationConfirmation that it discharges outdoors, not into an attic or soffit.