Connect the vent hose to the dryer outlet, then run it to the outside wall or roof
A dryer vent connection is straightforward: you attach a flexible or rigid duct to the outlet on the back of the dryer, find it with a hose clamp, and route it outside through the nearest exterior wall or roof. The entire job takes 30 to 60 minutes and requires only basic tools — a screwdriver, hose clamp, duct tape, and a drill if you need to cut through drywall. The vent must reach outside; venting into an attic, crawlspace, or interior wall will trap moisture and create mold and fire risk.
Most building codes require the vent to be as short and straight as possible, with no more than two 90-degree bends. Every bend adds resistance and reduces airflow, which means your dryer works harder and takes longer to dry clothes. A vent that is too long or has too many turns will also trap lint, which is a fire hazard.
Key Takeaways
- The vent hose connects to a metal outlet on the back of the dryer and must be secured with a hose clamp rated for the duct diameter.
- Flexible foil or semi-rigid aluminum duct works for most installations, but rigid metal duct is more durable and resists crushing better over time.
- The vent must exit through an exterior wall or roof with a damper hood that opens when the dryer runs and closes when it stops.
- Keep the vent run under 25 feet long and limit bends to two 90-degree turns; every additional bend reduces drying efficiency by about 5 feet of equivalent length.
- Inspect and clean the vent duct and hood at least once a year to prevent lint buildup, which is the leading cause of dryer fires.
Gather the right duct material and hardware
You have three choices for duct: flexible foil, semi-rigid aluminum, or rigid metal. Flexible foil is the cheapest and easiest to route around obstacles, but it crushes easily and traps lint inside the ridges. Semi-rigid aluminum is a middle ground — it bends but holds its shape better than foil. Rigid metal duct is the most durable and resists lint buildup, but it requires more planning because you cannot bend it to fit tight spaces.
Buy duct that matches the outlet diameter on your dryer — most are 4 inches. You will also need a hose clamp (also called a duct clamp) sized for that diameter, duct tape rated for high heat, and a damper hood for the exterior exit. The damper hood is essential: it prevents outside air, pests, and rain from entering the vent when the dryer is off. Look for a hood with a spring-loaded or magnetic damper that opens easily when air flows out.
If your vent run is longer than 8 feet or includes bends, buy a duct brush or lint trap designed for your duct diameter. These tools make cleaning easier and help catch lint before it travels far down the duct.
Disconnect the old vent and prepare the dryer outlet
Unplug the dryer from the electrical outlet or turn off the circuit breaker. If the dryer is gas-powered, also turn off the gas supply at the shutoff valve behind the unit. Wait a few minutes for any residual heat to dissipate.
Locate the vent outlet on the back of the dryer — it is a metal collar or fitting protruding from the rear panel. If a vent is already connected, loosen the hose clamp with a screwdriver and slide the old duct off. Wipe away any lint or dust from the outlet with a dry cloth. Inspect the outlet for damage; if it is cracked or dented, the dryer may need repair before you proceed.
Attach the new duct to the dryer outlet
Slide one end of the new duct over the dryer outlet. Push it on firmly so it overlaps the outlet by at least 1 inch. Position the hose clamp around the duct where it meets the outlet, then tighten the clamp with a screwdriver until it is snug — do not over-tighten, as this can crush the duct. The clamp should be tight enough that the duct does not slide off by hand, but not so tight that you deform the metal.
Wrap the joint with high-temperature duct tape as a backup seal. Tear off a piece about 2 inches wide and wrap it around the seam where the duct meets the outlet, overlapping the tape by half its width as you go around. This prevents lint from escaping at the connection.
Route the duct to the exterior and find it
Plan the shortest path from the dryer to an exterior wall or roof. Measure the distance and note where you will need to make bends. If the duct must pass through a wall, you will need to drill a hole slightly larger than the duct diameter — typically 4.5 to 5 inches for a 4-inch duct. Use a drywall saw or hole saw bit to cut cleanly.
Lay out the duct run and find it with duct straps or metal brackets every 3 to 4 feet. Do not let the duct sag or kink, as this traps lint and reduces airflow. If you are using flexible duct, avoid sharp bends; instead, make gradual curves. If you must make a 90-degree turn, use an elbow fitting designed for your duct size rather than forcing the duct to bend sharply.
Where the duct passes through a wall or roof, use a duct collar or boot to seal the opening. This prevents air leaks and keeps pests out. Caulk around the collar with silicone or polyurethane sealant rated for exterior use.
Install the damper hood on the exterior exit
The damper hood is the final piece. It attaches to the end of the duct on the outside of your home and allows moist air to escape while blocking rain, insects, and outside air from entering. Slide the duct into the hood opening and find it with a hose clamp, just as you did at the dryer. Wrap the joint with high-temperature duct tape.
Mount the hood to the exterior wall or roof with the fasteners provided — usually screws or bolts. Make sure the damper flaps move freely and are not blocked by lint or debris. Test the damper by hand to confirm it opens and closes smoothly.
If you are venting through a roof, use a roof flashing kit to seal the opening and prevent leaks. Slide the flashing under the shingles above the hole and over the shingles below, then nail and caulk it according to the kit instructions.
Test the connection and check for leaks
Plug the dryer back in or turn the circuit breaker back on. If it is gas, turn the gas supply back on. Run the dryer on a short cycle — 15 to 20 minutes — and watch for the following: the damper hood should open and stay open while the dryer runs, moist air should flow out steadily, and you should not see lint escaping around any joints.
Go outside and feel the air coming from the hood. It should be warm and moist. If the airflow is weak, the duct may be kinked, too long, or have too many bends. If you see lint around the hood or at any joint, tighten the hose clamps and add more duct tape.
After the test cycle, turn off the dryer and wait a minute. The damper should close completely. If it stays open or closes slowly, the damper may be stuck or the duct may be clogged with lint. Clean the duct with a brush before running the dryer again.
Maintain the vent to prevent lint buildup and fire risk
Lint is the enemy of dryer vents. It accumulates inside the duct, on the damper flaps, and in the hood, reducing airflow and creating a fire hazard. Clean the vent at least once a year, or more often if you dry large loads frequently or notice that clothes take longer to dry.
Start by unplugging the dryer. Remove the lint trap from inside the dryer door and empty it. Then disconnect the duct from the dryer outlet and use a duct brush or lint trap to pull out accumulated lint. Push the brush through the entire length of the duct, working from the dryer end toward the exterior end. Go outside and clean the damper hood and flashing as well.
If lint is packed tightly or the duct is long, you may need a dryer vent cleaning kit with a flexible rod that attaches to a power drill. These kits are inexpensive and make the job faster. Never use a vacuum cleaner inside the duct, as lint can clog the vacuum motor.
Frequently Asked Questions
Can I use PVC pipe or flexible plastic duct for a dryer vent?
No. PVC and plastic ducts are not rated for the heat and moisture a dryer produces. They can warp, crack, or release toxic fumes. Use only foil, semi-rigid aluminum, or rigid metal duct rated for dryer venting. Check the packaging to confirm it is approved for high-temperature use.
What if I cannot vent outside because my dryer is in the middle of the house?
You have limited options. The best solution is to relocate the dryer closer to an exterior wall or roof. If that is not possible, you can run a longer duct run, but every foot of additional length and every bend reduces efficiency. Some people use a condensing dryer, which collects moisture in a tank instead of venting it, but these dry clothes more slowly. Never vent into an attic or crawlspace.
How long should a dryer vent duct be?
Keep it under 25 feet if possible. Most building codes allow up to 35 feet, but every foot over 25 feet reduces drying efficiency. Each 90-degree bend counts as an additional 5 feet of equivalent length, so a 20-foot duct with two bends performs like a 30-foot straight duct. Shorter is always better.
Do I need a damper hood, or can I just cut a hole in the wall?
You must use a damper hood. A bare hole allows rain, cold air, and pests to enter when the dryer is off. The damper hood closes automatically and protects your home. It also helps contain lint and makes cleaning easier.
What if the duct is crushed or kinked after installation?
A crushed duct traps lint and reduces airflow, so it should be replaced or straightened. If it is flexible duct, you may be able to gently reshape it by hand or with a duct straightener tool. If it is semi-rigid or rigid duct, replacement is usually the only option. Do not leave a kinked duct in place, as it will accumulate lint and become a fire risk.