Dryer Vent Repair in Los Angeles

A dirty vent is a sound duct with lint in it. Clear the lint and it works again for a long time. A defective vent is a duct that restricts airflow or leaks even when it is clean — and because it restricts airflow, it fills with lint far faster than a sound one.

The giveaway is how quickly the problem comes back. If a run was cleaned and the dryer is slow again within a few months, the duct is the likely cause. Routine dryer vent cleaning usually turns this up, because a crushed section or a loose joint shows itself when the run is opened.

Flexible plastic or vinyl duct — the white accordion kind — and thin foil duct share three weaknesses. The ridged walls hold lint in every fold. They crush and kink easily, often out of sight. And plastic duct softens with heat and burns, which is the last thing you want wrapped around a lint deposit.

Dryer manufacturer installation instructions typically call for rigid or semi-rigid metal duct. Rigid duct is smooth-walled sheet metal, used for the fixed run through walls, floors and ceilings. Semi-rigid duct is metal that bends by hand and holds its shape, used for the short connection behind the dryer. Smooth walls move more air and hold less lint, which is why a dryer duct replacement often shortens drying times on its own.

The transition hose is the short flexible section between the dryer outlet and the duct in the wall. Every time the dryer is pushed back, the hose takes the load. A hose squashed to half its width halves the opening at the one point every bit of exhaust has to pass.

It also comes loose. A hose held on by tape or a worn clamp slides off the outlet when the dryer is moved, and the dryer then blows lint and moist air into the closet or the wall cavity. Replacing it means a new length of semi-rigid duct, clamped at both ends, with the dryer set far enough from the wall that the hose is not compressed. Recessed dryer vent boxes, set into the wall behind the dryer, exist for exactly this problem where space is tight.

The dryer manufacturer's installation manual sets a maximum equivalent length for the vent, and every bend counts against it. Equivalent length means the straight duct plus an allowance for each elbow, because a turn slows the air as much as a stretch of straight pipe would. A run can be well within the limit on a tape measure and over it once the bends are counted.

To reroute a dryer vent is to rebuild the path so it is shorter or straighter. That can mean a new exit through the nearest exterior wall instead of a long run to the roof, replacing two sharp elbows with gentler ones, or taking out a loop that was added only to reach an old opening. Sometimes moving the dryer a few feet does more than any change to the duct.

Where a run genuinely cannot be shortened, some installations add a booster fan made for dryer exhaust. It is a fix with its own upkeep — a fan in a lint stream needs cleaning too — and it is worth asking whether a shorter route exists before relying on one.

A wall termination is usually the better one. The run is shorter, lint does not have to be lifted, and the hood can be checked and cleaned from the ground. Its weakness is debris: a low hood behind shrubs collects leaves and is an easy target for nesting birds.

A roof termination is sometimes the only route out of an interior laundry room. It means a vertical rise, where lint falls back toward the dryer, and a cap that nobody sees until it fails. A roof cap designed for a bathroom fan rather than a dryer often has openings or a screen that catch lint.

Either way, a dryer vent hood or cover replacement is due when the flap is missing, cracked, painted shut, or covered with mesh. The replacement should have a damper that opens under the dryer's airflow and falls shut when it stops.

Where a condo or apartment has its laundry in an interior closet, the vent cannot go straight out. It travels through a ceiling or a chase to the nearest outside wall or up to the roof, and in a stacked building that can mean a long run with several bends that nobody in the unit has ever seen. Those are the runs most likely to be over the dryer's maximum equivalent length, and the hardest to check from inside the unit.

The same applies to houses where the laundry was moved from the garage to the middle of the house during a remodel. The duct had to get longer to reach an outside wall, and it was not always done in metal.

In a condo, find out who is responsible for the duct before anything is opened: the section inside the unit and the section in common walls or the roof are often treated differently by the association. Buildings with many units on similar runs, and shared laundry rooms, are covered on multi-unit and commercial properties.