The best place to vent a dryer depends on your home's structure and local building codes
Most dryers must vent to the outside of your home — either through an exterior wall, the roof, or a basement rim joist. The vent carries hot, moist air and lint away from your dryer and out of the house. Where you can run that vent depends on what your home allows, what your local code requires, and whether you are venting a gas or electric dryer.
Venting indoors — into a basement, attic, or crawlspace — is not permitted by most building codes and will damage your home by trapping moisture. The only exception is a condensing dryer, which cools the air and drains the water instead of venting it outside, but those are expensive and less common.
Key Takeaways
- Exterior wall vents are the shortest and most efficient route, requiring only a hole through the wall and a duct to the outside.
- Roof vents work but collect lint and ice more easily than wall vents, and they are harder to clean from the ground.
- Basement rim joists and band boards are a practical option if your dryer sits in a basement and the rim joist faces outside.
- Venting into an attic, crawlspace, or basement without an exterior exit will void your dryer warranty and create mold and structural damage.
- Local building codes vary by jurisdiction, so check with your city or county before cutting holes or running new ductwork.
Exterior wall vents are the most common and easiest option
An exterior wall vent is a hole cut through an outside wall, with a duct running from the dryer to the outside. This is the shortest path for air to travel and the easiest to install, whether you are doing it yourself or hiring someone. The vent opening sits flush with the wall or slightly recessed, and a damper flap on the outside closes when the dryer is off to keep cold air and pests out.
The main limitation is location: you need an exterior wall close enough to the dryer that you can run ductwork without excessive bends. If your dryer is in a basement and the nearest outside wall is far away, or if the wall faces a neighbor's property, a wall vent may not be practical. If the wall is brick or stone, cutting through it costs more than drywall or vinyl siding.
Wall vents also need regular cleaning because lint accumulates at the vent opening on the outside. Lint buildup reduces airflow and can trap moisture, so check the outside vent every few months and clear away any debris.
Roof vents work but require more maintenance
A roof vent runs ductwork up through the attic and out through the roof. This option works when no suitable exterior wall is available, or when the dryer is in a central location and a wall vent would require very long ductwork. Roof vents are less efficient than wall vents because the air has to travel upward and the duct is longer, which means more lint settles inside the duct.
Roof vents also collect ice in cold climates and are harder to inspect and clean from the ground. If you choose a roof vent, plan to have the ductwork cleaned professionally every year or two, especially if you dry heavy loads frequently. A clogged roof vent can cause moisture to back up into the attic, leading to mold and rot.
Make sure the ductwork runs through the attic without sagging or kinking, because low spots trap lint and water. The duct should slope slightly upward toward the roof to help moisture drain back toward the dryer.
Basement rim joists and band boards for below-grade dryers
If your dryer is in a basement, you can vent through the rim joist or band board — the horizontal beam that sits on top of the foundation wall where the basement meets the outside. Drilling or cutting a hole through the rim joist and running ductwork to the outside is faster than running ductwork up through the house to a wall or roof vent.
This option only works if the rim joist faces the outside of the house and is not buried underground. If your basement is partially below grade, the rim joist on the buried side will not work. You will need to run ductwork to a wall or roof vent instead.
Rim joist vents are vulnerable to water intrusion if they are not sealed properly, so use a vent hood with a damper and caulk around the ductwork where it enters the rim joist. Check the seal every year, especially after heavy rain or snow.
Never vent into an attic, crawlspace, or unvented basement
Venting a dryer indoors — into an attic, crawlspace, or basement without an exterior exit — is prohibited by building codes in all states. A dryer produces roughly 5 gallons of water per load, and that moisture has nowhere to go if it is not vented outside. The water condenses on framing, insulation, and stored items, creating mold, rot, and structural damage that can take years to become visible.
Indoor venting also voids the dryer's warranty and can trigger a fire if lint accumulates in an enclosed space. Some older homes have dryers that vent into basements or crawlspaces, but those installations are not safe and should be corrected.
The only exception is a condensing dryer, which cools the exhaust air inside the unit and drains the water into a tank or directly into a drain line. Condensing dryers do not require an exterior vent, but they cost significantly more than standard dryers and dry clothes more slowly.
Check your local building code before you install or move a vent
Building codes vary by city and county, and some jurisdictions have specific rules about where dryer vents can be located. Some codes prohibit roof vents in certain areas, require vents to be a minimum distance from windows or doors, or mandate that vents be inspected before a home can be sold. A few jurisdictions require a permit before you cut a hole in an exterior wall or roof.
Contact your local building department or code enforcement office before you plan a new vent location. They can tell you what is allowed, whether you need a permit, and whether an inspector needs to sign off on the work. This step takes a phone call and can save you from having to move a vent after it is installed.
Ductwork material and length matter for airflow
The duct that carries air from the dryer to the outside should be rigid metal or semi-rigid metal, not flexible plastic or vinyl. Flexible plastic ducts trap lint more easily, can kink, and are a fire hazard if lint builds up inside. Rigid metal ducts are smoother, easier to clean, and safer.
The duct should be as short and straight as possible. Every 45-degree bend adds resistance to airflow, and long runs with multiple bends force the dryer to work harder and dry clothes more slowly. If the duct is longer than 25 feet, or if it has more than four bends, the dryer's performance will suffer noticeably.
Insulate the ductwork if it runs through an unheated space like an attic or crawlspace. Insulation prevents moisture from condensing inside the duct and reduces heat loss, which improves drying efficiency.
Frequently Asked Questions
Can I vent my dryer into the garage?
No. Venting into a garage is not permitted by building code because the moisture and lint will accumulate in the garage, and lint is a fire hazard near vehicles and fuel. The dryer must vent to the outside of the home.
What if my dryer is in the middle of the house and far from any exterior wall?
Run ductwork to the nearest exterior wall or roof vent, even if the duct is long. A long duct is better than an indoor vent. If the run is very long, consider a condensing dryer instead, which does not require an exterior vent, though it costs more and dries more slowly.
Do I need to hire a professional to install a dryer vent?
If you are comfortable using a drill and cutting tools, and the vent location is straightforward (a nearby exterior wall), you can do it yourself. If the vent requires cutting through brick, running ductwork through walls, or venting through the roof, hiring a contractor is safer and faster.
How often should I clean my dryer vent?
Clean the lint trap after every load. Inspect the exterior vent opening every few months and clear away lint and debris. If you have a roof vent or a very long duct run, have the entire ductwork cleaned professionally every one to two years.
Can I use a flexible dryer vent hose instead of rigid metal duct?
Flexible hose is not recommended because it traps lint more easily, can kink and restrict airflow, and is a fire hazard. Use rigid or semi-rigid metal duct instead. Flexible hose is acceptable only as a short connector between the dryer and the main duct, and even then it should be as short as possible.