The basic connection: duct, clamps, and the wall
A dryer vent hookup means connecting the exhaust port on the back of your dryer to ductwork that carries warm, moist air outside. The connection itself is straightforward: a flexible or rigid metal duct slides onto the dryer's outlet, gets secured with a hose clamp or band clamp, and runs to either a wall vent or a longer duct system that exits your home. Most people can do this in 15 to 30 minutes with basic tools.
The duct material matters. Flexible aluminum duct (the accordion-style tubing) is easiest to install around corners and obstacles, but it can sag and trap lint if not supported. Rigid metal duct (smooth, straight sections) resists lint buildup better and lasts longer, but requires more planning and elbows to navigate around obstacles. Many building codes now discourage or ban the plastic-looking flexible duct called dryer vent hose because it's a fire hazard—check your local code before buying.
You'll need the duct itself, at least two hose clamps (stainless steel or aluminum, sized to fit your duct diameter), a screwdriver or socket wrench, and a vent hood or wall cap if you're installing a new exit. A duct brush or lint trap is not part of the hookup but should be installed inside the duct to catch lint before it clogs the system.
Key Takeaways
- Slide the duct onto the dryer outlet and tighten two clamps—one at the dryer end and one where the duct enters the wall or longer duct run—to prevent air leaks and lint escape.
- Use rigid metal duct or flexible aluminum duct, never plastic dryer vent hose, which is a fire hazard and banned in many jurisdictions.
- Keep duct runs as short and straight as possible; every elbow and long horizontal section slows airflow and increases lint buildup.
- Install a lint trap or duct brush inside the duct system to catch lint before it reaches the wall vent or roof cap.
- Test the connection by running the dryer on air-only mode and feeling for warm air at the outside vent; no air means a blockage or loose clamp.
Measuring and choosing your duct diameter
Most household dryers have a 4-inch exhaust outlet, which means you need 4-inch duct. Some older or compact dryers use 3-inch outlets. Check your dryer's manual or measure the outlet opening before you buy duct—buying the wrong size means a poor seal and wasted air.
Once you know the diameter, measure the distance from the dryer outlet to where the duct will exit your home (through a wall, the roof, or into an existing duct system). Add a few feet for bends and elbows. If the run is longer than 25 feet, or if you're using more than two elbows, you may need to upgrade to a larger duct or install a booster fan to maintain airflow—ask the duct supplier or your dryer manual for guidance on your specific setup.
Step-by-step connection at the dryer
First, unplug the dryer or turn off its circuit breaker. Slide the duct onto the dryer's exhaust outlet—it should fit snugly but not require force. If it's too loose, you have the wrong diameter; if it's too tight, the duct may be slightly crushed and won't seal properly.
Once the duct is seated, place a hose clamp around the connection point where the duct meets the dryer outlet. Tighten the clamp with a screwdriver or socket wrench until it's snug—not so tight that you crush the duct, but tight enough that you cannot slide the duct by hand. The clamp should be within an inch of the dryer outlet to create a seal that stops lint and air from escaping into the wall or crawlspace.
If your duct run is long or has multiple elbows, add a second clamp where the duct enters the wall or transitions to a longer run. This prevents the duct from sagging or disconnecting under its own weight or vibration from the dryer.
Running duct through walls and to the outside exit
If you're running duct through a wall to the outside, drill or cut a hole slightly larger than your duct diameter. Slide the duct through and find it on the outside with a wall vent cap or hood—the cap prevents rain and pests from entering and allows air to escape. Caulk around the cap on the outside to seal gaps and prevent water intrusion.
If the duct run is longer—for example, from a basement dryer to a roof vent—use rigid metal duct sections connected with elbows and couplings. Each connection should be sealed with a hose clamp. Rigid duct is heavier, so support it with metal straps or hangers every 4 to 6 feet to prevent sagging. Avoid running duct horizontally for long distances; if you must, slope it slightly downward toward the exit so condensation drains out rather than pooling inside the duct.
Never vent a dryer into an attic, crawlspace, or interior wall cavity. The moisture will rot framing and insulation, and lint will accumulate in spaces where it cannot be cleaned. Always vent to the outside.
Installing a lint trap or duct brush
A lint trap (also called a duct lint trap or lint interceptor) is a small chamber that sits inside the duct run and catches lint before it travels to the wall vent. It has a removable screen or basket that you empty after each load or every few loads. Installing one adds a few minutes to the hookup but saves you from having to disassemble ductwork to clean out lint later.
Slide the lint trap onto the duct between the dryer outlet and the wall vent, and find it with clamps on both sides. Some lint traps have a hinged door so you can empty them without disconnecting duct. If you don't use a lint trap, install a duct brush—a flexible brush on a rod that you push through the duct periodically to dislodge lint. Neither replaces cleaning the dryer's lint screen after every load, but both extend the time between professional duct cleanings.
Testing the connection and checking for leaks
Once the duct is connected and secured, plug the dryer back in or turn the circuit breaker on. Set the dryer to air-only mode (no heat) and run it for a few minutes. Feel the outside vent cap or wall opening—you should feel warm air flowing out steadily. If you feel little or no air, the duct may be kinked, a clamp may be too tight and crushing the duct, or the duct may be disconnected somewhere along the run.
Check all visible clamps to make sure they're tight and the duct is not sagging or pinched. If the duct is flexible, straighten any kinks by hand. If the problem persists, disconnect the duct at the dryer and check that the outlet is clear of lint or debris. Reconnect and test again.
You can also check for leaks by holding a tissue near the dryer outlet and the duct connection while the dryer runs—any air escaping will flutter the tissue. If you see air leaking around a clamp, tighten it further. If air is leaking where the duct meets the dryer outlet, the duct may be the wrong diameter or the outlet may be damaged.
When to call a professional
If your dryer is in a location where the duct run is longer than 35 feet, requires more than three elbows, or needs to go through multiple walls or the roof, hire a professional. They have the tools to install rigid duct properly, support it correctly, and seal all connections. A poor long-distance duct run will clog with lint and reduce dryer performance within months.
Also call a professional if your dryer outlet is damaged, if you're unsure about your local building code for vent materials, or if you need to install a booster fan. If you've connected the duct but the dryer still runs hot and takes a long time to dry clothes, the duct may be partially blocked—a professional can clean it with a power brush or camera to find the blockage.
Frequently Asked Questions
Can I use flexible plastic dryer vent hose?
No. Plastic hose is a fire hazard because lint can accumulate inside and ignite from the dryer's heat. Most building codes ban it. Use flexible aluminum duct or rigid metal duct instead.
How tight should the hose clamp be?
Tight enough that you cannot slide the duct by hand, but not so tight that you crush or dent the duct. If you crush the duct, airflow is blocked. Tighten until snug, then try to move the duct—if it doesn't budge, the clamp is tight enough.
What if the dryer outlet is on an interior wall with no straightforward way to vent outside?
You must vent to the outside; there is no safe alternative. If the outlet is far from an exterior wall, run duct through the attic or crawlspace to a roof vent or wall cap. This is a longer job and may require professional installation, but it's the only code-compliant option.
Do I need to clean the duct after I hook it up?
Not when ready, but you should clean it annually or whenever the dryer takes longer than 45 minutes to dry a full load. A clogged duct reduces efficiency and is a fire risk. Use a duct brush or hire a professional duct cleaning service.
Can I connect two dryers to one vent?
No. Each dryer must have its own dedicated vent to the outside. Sharing a vent creates backpressure, reduces airflow, and traps moisture and lint in the duct. Install separate vents for each dryer.