A dryer vent that was run too far, bent too many times, or stopped short of the outside wall will fill with lint again a few months after every cleaning. When that happens the duct is the problem, and replacing the run is the fix. Call us at 972-475-4949 and describe where the dryer sits and where the vent comes out, and we can often tell which case you have before a visit.

When a New Run Beats Another Cleaning

Cleaning restores a duct that was installed properly. These are the cases where it will not.

The duct does not end outside. A vent that empties into an attic, a crawl space or a garage pushes hot, damp, lint-heavy air into the house instead of out of it. The Department of Energy’s guidance is plain on this: vent clothes dryers directly to the outdoors.

The run is longer than the limit once its bends are counted. This is common where the laundry sits upstairs or in the middle of the floor plan, far from an exterior wall.

It is foil, vinyl or plastic. Foil, vinyl and nylon ducts are not recommended and void the warranty on most dryers, and PVC pipe is not allowed for dryer exhaust under any of the standards. Flexible duct also sags between supports and holds lint in every dip.

The joints are screwed together. Screw tips that reach inside the duct catch lint and build a plug at each joint.

The laundry is moving, the room is being remodeled, or a new addition needs its first run put in.

Not sure which one applies? Schedule a visit to have the run measured rather than guessed at.

The Numbers a Dryer Vent Has to Meet

Texas adopted the International Residential Code as its municipal residential building code, and a city can amend it only by ordinance after holding a public hearing (Texas Local Government Code 214.212). Section M1502 of that code covers dryer exhaust, and the Department of Energy’s Building America Solution Center lays the same requirements out in plain terms in its guide to proper clothes dryer venting.

Requirement The number
Duct diameter 4 inches
Material Rigid or semi-rigid metal, galvanized steel or aluminum, smooth inside
Maximum length 35 feet, or as the duct manufacturer specifies
Deduction for each 45 degree bend 2.5 feet
Deduction for each 90 degree bend 5 feet
Support At least every 12 feet
Termination Outdoors, at least 3 feet from other openings
At the outlet A louvered backdraft damper with a hood, no screen over the end
Distance from the AC condenser At least 10 feet
Not allowed PVC pipe. Foil, vinyl and nylon are not recommended

The bend deductions are what catch most runs out. Four 90 degree turns take 20 feet off the allowance before a single foot of straight pipe is counted, which leaves 15 feet to reach the wall.

The Routes That Make an Install Harder

How practical a new run is comes down to where the dryer is and what stands between it and an outside wall.

Ground floor against an exterior wall. The simplest case: a short, straight run through the wall with the hood on the other side.

Upstairs laundry. The run has to travel down or across, which is where bends pile up and the 35 foot budget goes quickly.

Interior laundry room. There is no outside wall nearby, so the route crosses joists or rises into the attic and out, and every change of direction costs length.

Roof termination. Sometimes it is the only way out. It needs the right hood, and lint traveling upward tends to settle back, so it stays on the maintenance list.

Call us at 972-475-4949 with the room the dryer is in and the nearest outside wall, and we can talk through which of these routes you are looking at.

What a Code-Built Run Includes

We are an HVAC contractor, so we treat the vent as part of the house’s ventilation, not as a hole in a wall. A run built to the numbers above has:

  • A route measured and its bends counted against the 35 foot limit before any duct is fitted
  • Smooth 4 inch metal duct, with joints that follow the direction of airflow
  • Support along its length, so it cannot sag and hold lint
  • An outdoor termination clear of other openings, with a backdraft damper that closes when the dryer stops
  • At least 10 feet between the vent outlet and the AC condenser

If your existing duct turns out to be sound and simply full of lint, a new run is not needed. That is a dryer vent cleaning visit instead.

Why the Installation Decides the Fire Risk

The U.S. Fire Administration puts failure to clean at 31 percent of clothes dryer fires in homes from 2018 to 2020, the leading factor behind them (U.S. Fire Administration).

Installation decides how fast a duct gets back to that state. Every extra bend, every foot past the allowance and every screw tip inside the pipe is a place where lint stops moving. That is why the code counts bends against the length instead of only capping the distance, and why a smooth interior is part of the requirement.

Where We Work

Our shop is on Gordon Smith Drive in Rowlett, and most of our dryer vent work is in Rowlett, Rockwall, Sachse, Garland, Wylie, Sunnyvale and Mesquite. Call us at 972-475-4949 or book a dryer vent visit and tell us where the dryer is.