How to Install a Dryer Vent

Drying your clothes produces hot, humid air in your dryer. A dryer wall vent allows this air to escape through a system of ducts or pipes connected to the back of the dryer. Also called clothes dryer venting, this type of dryer duct installation removes moisture and lint so your clothes can dry. Without proper ventilation, your dryer won’t perform well if at all. Over time, moisture and lint can build up causing mold, mildew and even a fire hazard.

Figuring out how to install a dryer vent starts with choosing the best materials. PVC or plastic ducts are common because they’re easy to install but they can trap lint. For clothes dryer venting, a 4-inch, rigid aluminum or galvanized steel duct pipe is a better option. They let air flow more freely and reduce lint buildup.

Below are the tools and materials you’ll need:

• Measuring tape
• Drill
• Screwdriver
• Duct or pipe cutters
• Level
• Ladder
• Dryer duct
• Duct clamps
• Dryer wall vent and vent cover
• Gloves

Tip: If dryer noise is a problem, consider using insulated ducts that muffle sounds.

When figuring out how to install a dryer vent, first map out the shortest route from the back of the dryer to the outside of the house. Avoid a lot of turns or twists for the duct work. You don’t want places where lint can build up. Here are other guidelines to follow when venting a dryer:

• When installing a dryer vent for laundry centers in basement locations, the vent hood on your home's exterior must be at least 12 inches from the ground.
• A dryer duct should be 25 feet or less. Subtract 5 feet for each 90-degree turn and 2 1/2 feet for each 45-degree turn.
• Because washer and dryer pedestals have a higher height, they can require a shorter length of ductwork. Adjust your final duct work measurements for these types of appliances. This can also be true of washer and dryer stacking kits.
• Route the dryer vent horizontally to the home’s outside wall.
• Duct work should pitch 1/4-inch per foot to the outside. This keeps moisture out of the pipe.
• For basement laundry areas where your ductwork will run vertically to the outside wall, you may need to use 90-degree elbows.
• If your washer and dryer is in an upper-level room, check the manufacturer’s guidelines about venting through the roof.

Once you’ve figured out the shortest route for the ductwork, figure out where the dryer vent will exit. The vent hood on the exterior of your home must be at least 12 inches from the ground.

• Use a section of vent pipe to mark a circle where the opening will be from inside of your home.
• Drill a test hole in the center of the marked circle.
• Use a power drill fitted with a 1/4-inch pilot that is long enough to reach the outside.
• Check the hole from outside the home. Place the vent cap over the hole so that its top rests on the high point of the siding.
• If the hole is a little high or low, measure the distance from the pilot hole to the center of the vent cap duct.
• Transfer that measurement inside, if necessary, to mark the new dryer vent center.

If you are installing a dryer vent through a finished wall, remove a small section and check to be sure you won’t be cutting through any wiring, plumbing or ductwork.

• Use a 4 1/4-inch hole saw to cut the vent opening.
• Remove the hole saw frequently to keep it cool and to remove debris.
• Once the hole saw’s pilot bit pops through the exterior, go outside to complete the hole using the pilot hole as a guide.
• Finishing the hole from the opposite side will help make a smoother opening and minimize uneven splintering on the home’s exterior.
• If cutting through stucco or brick, use a hammer drill and a 1/4-inch masonry bit to create both the pilot hole and to cut out the vent hole.
• For masonry, drill closely spaced holes around the circumference of the circle that marks the opening. Then, chip the masonry away with a chisel.

After the hole is completed, get the dryer vent hood into place from the exterior of your home.

• Insert the duct pipe on the vent hood through the hole.
• Position the assembly so that the opening faces toward the ground.
• Secure the dryer vent hood to the siding on the home’s exterior using wood screws. For masonry homes, use appropriate anchors instead of wood screws.
• Caulk around the top and sides of the hood to seal it from the elements using an exterior-grade silicone caulk.
• Do not caulk along the bottom. Any moisture that might get behind the hood needs to escape.

With the vent hood securely in place, begin connecting the ductwork exit point with the back of the dryer.

• Duct pipe usually comes in 5-foot lengths. Cut straight lengths of rigid pipe using tin snips. When cutting rigid dryer duct pipe, wear gloves to protect your hands. Freshly cut edges of duct metal are extremely sharp and even light contact with an edge can cause injury.
• Depending on the location of your vent, you may require an elbow to connect to the vent hood duct. You may have two elbows back-to-back to get the run to line up the path from the dryer. Install a duct elbow onto the dryer, if necessary.
• Measure the distance between the elbows, including the overlap from the connection at each end.
• Assemble the cut pieces of duct pipe. Make sure that the crimped end of the pipe fits into the pipe above it. This allows the exhaust from the dryer to flow smoothly to the exit at the vent hood.

Each connection of duct pipe needs to be held together and any lengths of pipe longer than a few feet need to be supported.

• Attach the straight run to the elbow at the vent hood.
• Attach the other end of the straight run to the dryer, shifting the elbow or elbows as necessary to complete the connection.
• Use a carpenter’s level to ensure the runs slope slightly toward the vent exit.
• Attach hanger straps to support the duct, if necessary.
• Use foil tape wrapped around seams to seal connections. Do not use screws as these will collect lint inside the duct.

• Line up the ductwork with the exit vent behind the dryer.
• Slide the dryer back and secure the connection.
• Use a level to make sure it rests flat on the floor.
• Adjust the dryer legs as necessary and then lock them into place.
• Turn on the dryer to test the flow of the dryer vent installation.
• Go outside and see if the louver or flap on the vent hood is operating.
• If there is no airflow or airflow is weak, re-check all your duct connections.

• A gas dryer should never be vented into a garage or any other enclosed space. Gas dryers expel carbon monoxide, an odorless, colorless gas. It can be harmlessly vented into the open air. Otherwise, it builds up and is lethal to people and pets.
• Never use sheet metal screws because the fasteners catch lint, which is a fire hazard.
• Seal any duct joints using foil duct tape.
• Insulate the duct in areas without climate control. This will keep the moist air from condensing and minimize lint build-up within the pipe.
• Never use flexible vinyl ductwork to vent a clothes dryer as these pose a serious fire hazard.
• Semi-rigid and flexible ductwork can collect more lint, so clean these types of ducts more frequently.
• Regularly check for clogs and clean out lint and debris.