How to Hook Up and Install Dryer Vents

How to install a rigid metal duct for a safer dryer.

Next Project

A full day






To speed up clothes drying and prevent lint build-up, install a smooth metal dryer vent. These step-by-step directions walk you through the tough parts. Rigid metal vents are safer than flexible plastic and metal types, which catch more lint, require more cleaning and can retard airflow. Even worse, flexible ducts are easily crushed, which blocks airflow and causes the dryer to overheat, which in turn can lead to lint fires. In this story, we'll show you how to cut and install 4-inch rigid metal duct, including the toughest part—drilling the exit hole through an exterior wall.

Tools Required

  • 4-in-1 screwdriver
  • Caulk gun
  • Corded drill
  • Drill bit set
  • Tape measure
  • Tin snips

Materials Required

  • 4-in. duct
  • 4-in. elbows
  • Duct cap
  • Exterior caulk
  • Foil tape
  • Pipe straps
  • Vent cap

Video: How to Install and Upgrade Your Dryer Vent

Project step-by-step (14)

Step 1

Choose the Shortest Route for the Vent

From an Underground Basement

  • If your dryer is in the basement and the basement is underground, run duct up the exterior wall and out the rim joist.
  • Set the vent a minimum of 12 inches above the outside ground.
    • Pro tip: Use no more than 25 feet. of 4-inch duct, and subtract 5 feet for every 90-degree turn and 2 1/2 feet for every 45-degree turn for dryer vent installation. For example, a dryer with a 90-degree elbow at the exhaust port and another at the top of the basement wall can run a maximum of 15 feet.

How to Install Dryer Vents

Straight Path From the Basement

  • If the dryer is against an exterior wall that is not underground, run the duct straight out from the back of the dryer.
  • Set the vent a minimum of 12 inches above the outside ground.
    • Note: This is the simplest, most ideal solution. The shorter the distance and fewer the turns the better for dryer vent installation.

How to Install Dryer Vents

Through the Attic to the Roof

  • If the dryer is an interior room of the house, vent through the attic to the roof.
    • Note: Vent a dryer through the roof only as a last resort. Cleaning lint buildup from roof vents is difficult, and nesting birds and squirrels often find roof vent caps irresistible.

How to Install Dryer Vents

Step 2

Go Shopping

  • Once you’ve decided on a vent location and planned the dryer duct route, measure the length of the run, allowing for bends.
  • Buy enough straight duct and fittings to complete the job, including an outdoor cap.
    • Pro tip: Use either galvanized steel (our choice) or aluminum duct, but don’t mix parts.

Step 3

Drill a Test Hole in the Rim Joist

  • Mark the center of the rim joist and drill a test hole with a 1/4-inch bit.
  • Locate the hole outside and check for obstructions.
    • Pro tip: If the hole is a little low or the cap doesn’t sit in the best position on the siding, it’s not too late to adjust it. If it’s really wrong, you can easily fill the hole and start over at a different location. 

Step 4

Adjust the Hole to Fit the Siding

  • Shift the hole so the top of the vent cap rests on the high point of the lap siding.
  • Pull the vent cap and duct apart to make measuring easier.

dryer vents

Step 5

Drill the Vent Hole in the Siding

  • Bore a 4-1/4 inch hole with a hole saw.
    • Pro tip: Hold the drill level and steady. Pull the drill back frequently to clear the sawdust and let the drill motor cool.

Step 6

Drill Through the Rim Joist

  • Stop and pry out siding and sheathing from the saw as you go.
  • Continue your cut through the rim joist.

dryer vents

Step 7

Install the Vent Cap

  • Insert the vent and screw the cap to the house (predrill screw holes).
  • Push foam backer rod into deep gaps.
  • Caulk all around with acrylic caulk.

How to Mount a Vent Cap on Vinyl Siding

There are two good ways to install dryer vents through vinyl siding. The first is to install a vinyl surface mounting block (shown here) that fits over the existing siding. You may need to scribe and trim the edges to precisely fit your siding profile. Fasten the surface mounting block to the house with screws, but remember to drill slightly oversize holes through the vinyl to allow for siding movement.

The second method is to remove a section of siding and install a special vinyl mounting block (not shown) against the sheathing. Cut the siding to fit around it. Both are available from vinyl siding dealers.

Holding cap over siding

How to Make the Vent Hole in Stucco and Brick Veneer

Getting through stucco and brick requires different techniques and tools than for wood and vinyl. You’ll need a masonry bit with a hammer drill for your pilot hole. Then trace a 4-1/2 in. circle and drill a series of closely-spaced holes around the circumference with the 1/4-in. masonry bit and hammer drill. Break out the masonry with a cold chisel. Snip the wire mesh back if you’re chipping out stucco. Then drill through the wood sheathing and framing with a 4-1/4 in. hole saw.

Chiseling the siding

Step 8

Cut the Vent to Length

  • Cut the straight sections to length with tin snips before you snap the seams together.
    • Pro tip: Wear leather gloves—the cut metal edges are sharp.

Step 9

Close the Seam on the Vent

  • Align the seam edges of the duct.
  • Working from one end, push the edges down slightly as you force them together.

Step 10

Tape the Elbow Joints

  • Start at the dryer and insert the crimped end of the first elbow into the first straight section.
  • Tape the joints with metal foil tape.

Step 11

Attach the First Vent Section

  • Slide the first fitting onto the dryer and push the dryer against the wall.
  • Measure, cut and assemble the other duct sections.

Step 12

Install the Remaining Vent Sections

  • Slide the last elbow onto the straight section coming up the wall.
  • Push the crimped end of the elbow into the duct cap section and tape it.

Step 13

Secure the Vent to the Wall with Straps

  • Anchor the duct to walls or ceilings every 6 to 8 feet with a pipe strap.
    • Pro tip: Loop the strap around the duct; don’t screw the strap to it.

Step 14

Turn on the Dryer

  • Plug the dryer in and turn it on.
  • Check outside to make sure the vent flap is opening.

A Note on Cleaning

Lint buildup reduces dryer efficiency, which means clothes take longer to dry. Check the vent cap frequently and brush out the lint. At least once a year, snake a vacuum hose into the dryer duct to clean it. Tapping on the dryer duct while you do this will help knock off lint that’s stuck to the sides and joints. To avoid fires, vacuum lint from around dryer drums, burners and motors at the bottom of the cabinet. Here are a few tips for cleaning your dryer vent.