Learning how to install a dryer vent involves some planning and attention to detail, but it’s an essential step of dryer installation. Venting a dryer removes the warm, moist air created from forced heat evaporating the water from your freshly washed laundry. The dryer’s output may be mixed with hazardous gases such as carbon monoxide which is a byproduct of combustion. This guide teaches you how to hook up a dryer vent properly, whether you are venting a gas dryer or an electric dryer.
Safety Tip: If venting a gas dryer, check with local building codes or manufacturer’s instructions. Maintain safe clearances around windows and other potentially problematic areas.
Plan the Dryer Vent Path
The first step of installing a dryer vent in a new location is to map out a path for the ductwork. The route should be as short as possible but there are other guidelines to follow when venting a dryer:
- The typical maximum-allowable duct run for dryers is 25 feet. The final length depends on the model dryer and type of dryer duct piping you choose. Check the manufacturer’s instructions for specifics.
- The rule-of-thumb for route length should be reduced for each turn in the path. Subtract 5 feet for each 90-degree turn and 2 1/2 feet for each 45-degree turn.
- Be sure to take into account distance adjustments created from appliances resting on top of washer and dryer pedestals. Washer and dryer stacking kits available for some appliance models can decrease the vertical length of ductwork by elevating the height of the dryer.
- Use a 4-inch rigid metal duct pipe for a safer option that also requires less maintenance.
- Semi-rigid and flexible ductwork varieties are prone to collecting more lint. Lint restricts air flow and these types of ducts need more frequent cleaning. Insulate the duct in unconditioned space to keep the moist air inside it from condensing. This will minimize lint build-up within the pipe.
- Never use flexible vinyl ductwork to vent a clothes dryer as these pose a serious fire hazard.
- Seal duct joints using foil duct tape. Never use sheet metal screws because the fasteners will catch lint, which is a fire hazard.
It’s best to route the dryer vent in a horizontal path to the home’s outside wall. All horizontal runs should pitch 1/4-inch per foot to the outside. This will help to avoid moisture from sitting in the pipe or draining back to the dryer. Some basement installations require a vertical ascent using 90-degree elbows to reach an outside wall.
If washers and dryers are located within an upper level interior room, it may be possible to vent through the roof depending on the dyer model, so be sure to check with the manufacturer’s guidelines.
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. However, the gas poses a danger when it is allowed to accumulate. If it builds up within the garage it will be lethal to people and pets. In addition, the dryer vent will raise moisture levels in the garage. This may contribute to a mold problem developing that could later require expensive remediation.
Cut the Vent Hood Opening
After locating the shortest route for the ductwork, determine the location of the dryer vent exit. When installing a dryer vent for laundry centers in basement locations, keep in mind that 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.
Install the Dryer Vent Hood
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. This way any moisture that might get behind the hood can escape.
Measure, Cut and Assemble Vent
With the vent hood securely in place, begin connecting the exit point and the dryer. 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.
- Duct pipe usually comes in 5-foot lengths. Cut straight lengths of rigid pipe using tin snips.
- Assemble the cut pieces of duct pipe, ensuring that the crimped end of the pipe fits into the pipe above it. This allows the exhaust from the dryer to flow smoothly to its exit at the vent hood.
Secure the Vent Ducts and Test
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.
- Use foil tape wrapped around seams to seal connections. Do not use screws as these will collect lint inside the duct.
Now slide the dryer into place and use the level to see that it rests flat on the floor. Adjust the dryer legs as necessary and then lock them into place. Then turn on the dryer to test the flow of the dryer vent installation. Go outside to check that the louver or flap on the vent hood is operating.
After installing a dryer vent, keep it clean. A clean dryer vent increases dryer efficiency and reduces potential fire hazards. Use a vacuum hose annually to remove lint from inside the duct. Check the vent hood frequently and brush out any visible buildup.
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