Why the material matters
A dryer vent carries hot, damp air with lint in it. Every type of duct below is a trade between how easy it is to install and three things that decide how well it does the job.
- How smooth the inside is, because lint catches on every ridge
- Whether it holds its shape, because a crushed or sagging duct chokes the airflow
- What it is made of, because metal does not burn and plastic does
Thin plastic or vinyl hose
This is the white, ribbed hose found behind many older dryers. It is not recommended. The ribs are deep and catch lint. The hose sags between supports and flattens when the dryer is pushed back. And the material itself can soften with heat and burn if lint inside it ever ignites.
Dryer makers and fire safety agencies say the same thing: use metal. If you find plastic or vinyl hose behind your dryer, do not wait for it to fail. Have it replaced. Our dryer vent replacement page explains what goes in its place.
Thin foil hose
Foil hose is the silver, slinky kind: a thin foil skin over a wire spiral. It is sold everywhere, bends anywhere and is quick to fit, which is why so many dryers have it.
It is a step up from plastic, but a small one. The ridges are just as deep. The skin tears and punctures easily. It crushes flat behind the machine and droops into low spots where lint and moisture collect. Some versions are a foil film laminated to plastic.
If foil hose is used at all, it belongs only in the open, as the visible connection between the dryer and the wall, kept as short and as straight as the space allows. It should never run inside a wall, floor or ceiling, where nobody can see it sag or tear.
Semi-rigid metal duct
Semi-rigid duct is corrugated aluminum that bends by hand and then holds the bend. Its walls are sturdier than foil hose and its ridges are shallower, so it catches less lint and keeps its shape.
This is the usual choice for the connection behind the dryer, where some flexibility is needed to line up the dryer's outlet with the opening in the wall. It can still be crushed if the dryer is shoved hard against it, so leave it room.
Rigid metal duct
Rigid duct is smooth-walled metal pipe, galvanized steel or aluminum, in straight lengths joined by elbows. The inside is smooth, so lint has little to hold on to and air moves through it more easily than through any flexible duct. It does not sag, crush or tear, and a brush passes through it cleanly when the time comes to clean it.
This is what belongs in the concealed part of the run, inside walls, ceilings and floors. It takes more work to install, because every length has to be cut and fitted. Each joint is wrapped in foil tape. Screws that poke into the airstream snag lint, and cloth duct tape dries out in the heat and lets go.
How to tell what you have
Pull the dryer away from the wall and look. White and ribbed is plastic or vinyl. Silver, crinkly and soft enough to dent with a fingertip is foil. Silver, stiffer and able to hold a bend is semi-rigid. Smooth pipe is rigid.
What is inside the wall is harder to judge. In a row house, part of the run is often exposed along the basement ceiling, so look there for flexible hose hanging in loops between the joists. In an apartment the run is usually hidden, and the way to know is to have someone look in from the ends.
The route matters as much as the material
Even good duct works badly on a bad route. The shortest, straightest path to the outdoors moves the most air and holds the least lint. Every extra turn slows the air down.
The line should end outdoors at a hood with a flap that opens when the dryer runs and closes when it stops. It should not end in a crawl space, an attic, a wall cavity or the basement itself. A screen over the outlet is a mistake, because lint mats on it.
Whatever the material, the line still needs cleaning. A smooth rigid duct just goes longer before it needs it. If yours is due, see dryer vent cleaning. A flattened hose or a loose joint is a job for dryer vent repair. If you are not sure what you have, text DRYER and your ZIP code to (917) 983-1283 and ask for a quote.
Related services
Call or text (917) 983-1283 for a quote.