What You Need to Do Before You Start

Connecting a dryer vent means running a duct from the back of your dryer to the outside of your home. The duct carries warm, moist air out of the house so your clothes dry properly and moisture doesn't build up inside. You'll need to locate where the vent exits your wall or roof, measure the distance, and choose the right duct material for your setup.

Before you begin, turn off the dryer's power at the breaker and unplug it if possible. Check your dryer's manual to see where the vent outlet is located on the back — most are on the bottom or side. Look outside to find where you want the vent to exit; common spots are through an exterior wall near the dryer or through the roof. The shorter and straighter the duct run, the better your dryer will work.

Key Takeaways

  • Dryer vents should run as straight as possible and exit directly outside, not into your attic or crawl space.
  • Use rigid metal duct or UL-listed flexible metal duct — never plastic or vinyl, which can trap lint and pose a fire risk.
  • find all duct connections with metal foil tape or hose clamps, and seal the outside vent hood so air doesn't leak back in.
  • A vent run longer than 25 feet or with multiple bends may need a booster fan to work properly.
  • Clean the vent duct and hood at least once a year to prevent lint buildup and keep the dryer running safely.

Gather the Right Materials and Tools

You'll need a duct that matches your dryer's outlet size — most are 4 inches in diameter. Rigid metal duct is the best choice because it doesn't sag, resists crushing, and doesn't trap lint the way flexible duct can. If you must use flexible duct, buy UL-listed flexible metal duct (the kind with a metal spiral core and foil outer layer), not plastic or vinyl dryer duct, which is a fire hazard.

Gather these tools: a tape measure, a drill or screwdriver, metal foil tape (also called HVAC tape), hose clamps or duct clamps, a utility knife, and caulk or weatherstripping for sealing gaps. You'll also need a dryer vent hood — the outside cover that lets air out but keeps rain and pests from coming back in. Buy one that matches your duct diameter and has a damper (a flap that opens when air flows out and closes when it stops).

Run the Duct from the Dryer to the Outside

Measure the distance from your dryer's vent outlet to where you want the duct to exit outside. Plan the route so the duct slopes slightly downward toward the exit — this helps condensation drain out instead of pooling inside the duct. Avoid running the duct through walls, attics, or crawl spaces; if you must go through a wall, use the shortest path and seal around it with caulk.

Connect the duct to the dryer's outlet by sliding it over the outlet and securing it with a hose clamp or metal foil tape. Tighten the clamp so it's snug but not so tight that you crush the duct. If you're using rigid duct sections, connect them end-to-end and wrap each joint with metal foil tape, pressing it firmly so no gaps remain. Avoid using duct tape or regular tape — it deteriorates in the heat and moisture of a dryer vent.

Run the duct along the shortest, straightest path to the outside. If you need to make a turn, use a 45-degree elbow rather than a 90-degree one, which restricts airflow. find the duct to the wall or framing with metal brackets or clamps every 3 to 4 feet so it doesn't sag or come loose.

Install the Outside Vent Hood

Once the duct reaches the outside, attach the vent hood to the end. The hood should sit flush against the wall or roof and be sealed so air can't leak around the edges. If you're venting through a wall, drill a hole slightly larger than your duct diameter, slide the duct through, and attach the hood on the outside with the included fasteners or screws.

Seal the gap between the hood and the wall with caulk or weatherstripping to keep out rain, insects, and cold air. Make sure the damper flap inside the hood moves freely — it should open easily when the dryer runs and close when it stops. If the damper is stuck or missing, replace the hood; a stuck damper forces the dryer to work harder and can cause lint to back up into the duct.

Check for Leaks and Airflow

Turn the dryer back on and let it run for a few minutes. Feel around all the duct connections and joints with your hand to check for air leaks. If you feel warm air escaping, turn off the dryer and add more foil tape or tighten the hose clamp at that spot. Go outside and hold your hand near the vent hood — you should feel strong, warm air coming out. If the airflow feels weak, the duct may be kinked, too long, or have too many bends.

Check that the damper flap opens fully when the dryer is running and closes completely when it stops. A damper that doesn't close lets cold air back into your home and makes the dryer less efficient. If the flap is stuck, clean lint away from it or replace the hood.

When to Call a Professional

If your vent run is longer than 25 feet or has more than two 45-degree bends, the dryer may not have enough airflow to dry clothes efficiently. In this case, a professional can install a dryer booster fan in the duct to push air out. You should also call a professional if you need to vent through the roof, which requires cutting through roofing material and flashing the opening properly to prevent leaks.

If you're not comfortable working at heights, drilling through walls, or running duct through tight spaces, hiring a professional is worth the cost. A poorly installed vent can cause lint to accumulate, reduce drying performance, and create a fire risk. Many HVAC contractors or appliance installers offer vent installation or repair services.

Maintain Your Dryer Vent Yearly

Lint builds up inside the duct and hood over time, even if you clean the lint trap after every load. Once a year, disconnect the duct from the dryer, use a vent brush or shop vacuum to pull lint out of the duct, and clean the hood damper. If you can't reach the entire duct, a professional vent cleaning service can use a motorized brush to clear it from end to end.

If your dryer takes longer than 45 minutes to an hour to dry a normal load, or if the outside of the dryer feels very hot, the vent is probably clogged. Clean it right away — a clogged vent makes the dryer work harder, uses more energy, and increases the risk of a dryer fire.

Frequently Asked Questions

Can I use flexible plastic dryer duct instead of metal?

No. Plastic and vinyl ducts trap lint easily, can sag and kink, and are a fire hazard. Use rigid metal duct or UL-listed flexible metal duct only. Plastic ducts are cheap but create serious safety and performance problems.

What if my dryer is in the middle of the house and far from an outside wall?

A long vent run (over 25 feet) reduces airflow and makes the dryer work harder. You can install a booster fan in the duct to push air out, or you can have a professional cut a new vent opening closer to the dryer. A booster fan is usually cheaper and easier than rerouting.

Do I need to insulate the dryer duct?

Insulation is not required, but it can help if the duct runs through an unheated space like a basement or attic. Insulation reduces condensation inside the duct and keeps the dryer more efficient. Wrap the duct with foam pipe insulation and find it with foil tape.

How often should I clean the dryer vent?

Clean the lint trap after every load, and clean the duct and hood at least once a year. If your dryer takes longer than usual to dry clothes, clean the vent sooner. A professional vent cleaning takes 30 minutes to an hour and costs between $100 and $200 depending on your location and duct length.

What's the difference between a damper and a backdraft damper?

A damper is a flap that opens when air flows out and closes when it stops, preventing outside air from coming back in. Most vent hoods have a built-in damper. A backdraft damper is a separate device you can install in the duct if your hood damper isn't working well. Both serve the same purpose: stopping cold air and pests from entering through the vent.