How to Clean a Dryer Vent (Step by Step)
April 13, 2026
Clogged dryer vents cause 2,900 house fires every year in the US. Beyond the fire risk, a clogged vent makes your dryer work harder, take longer, and use more energy... adding $18-$24/month to your electric or gas bill. Cleaning the vent takes 20-30 minutes, costs nothing if you already have a vacuum, and should be done once a year. Here's how to do it yourself.
Why This Matters More Than You Think
Lint passes through the lint trap screen every load... about 25% of it escapes into the vent system. Over a year, that lint accumulates in the vent duct, at bends, and at the exterior vent cap. When enough lint builds up, three things happen:
1. Airflow is restricted, so the dryer runs longer (clothes take 2-3 cycles to dry instead of 1) 2. Heat builds up in the duct, which can ignite the lint (lint ignites at about 480°F) 3. Moisture can't escape, leading to mold in the vent and potentially in the wall cavity
If your clothes take longer to dry than they used to, or the dryer is hot to the touch on top after a cycle, or the laundry room feels humid when the dryer is running... your vent needs cleaning.
What You Need
A dryer vent cleaning kit ($15-$25 at any hardware store or Amazon) is the easiest approach. It includes flexible rods that connect together and a brush head that fits inside 4-inch dryer duct. The rods attach to a drill for powered rotation, which scrubs the lint off the duct walls.
Alternatively, you can use a vacuum with a long hose attachment, a leaf blower (surprisingly effective for short, straight runs), or just disconnect the duct and shake/vacuum it by hand.
You'll also need: a screwdriver or nut driver (to disconnect the duct clamp), and optionally a flashlight to see inside the duct.
Step 1: Pull the Dryer Away from the Wall
Unplug the dryer (electric) or turn off the gas valve (gas dryer). Pull the dryer away from the wall enough to access the back. Be careful not to kink or damage the gas line if you have a gas dryer.
This is also a good time to vacuum behind and under the dryer. The amount of lint that accumulates back there is alarming... and it's a fire hazard too.
Step 2: Disconnect the Vent Duct from the Dryer
The flexible or rigid duct connects to the dryer's exhaust port with a clamp (usually a worm-drive clamp tightened with a screwdriver or nut driver). Loosen the clamp and slide the duct off the dryer port.
Look inside the duct opening on the dryer itself. There's often a thick buildup of lint right at this connection. Pull it out by hand or vacuum it.
Step 3: Clean the Duct from Inside
Insert the brush rod into the duct from the dryer end. If you're using a drill-powered kit, attach the brush to the drill and push it into the duct while spinning. The rotating brush scrubs lint off the duct walls and pushes it toward the exterior vent.
Add rod sections as you push deeper. Keep going until you reach the exterior vent cap. You'll feel less resistance as the duct gets cleaner.
If you don't have a kit, a vacuum hose inserted as far as it reaches works for the accessible portion. A leaf blower inserted into the dryer end blows lint out the exterior vent... messy but effective.
Step 4: Clean the Exterior Vent Cap
Go outside and find where the vent exits the house (usually a 4-inch cap on an exterior wall or through the roof). Remove the vent cap cover if possible and clear any lint buildup. This is often the most clogged spot because lint catches on the flap or screen.
If there's a screen over the exterior vent, consider removing it permanently. Screens catch lint and defeat the purpose of the vent. The flap damper alone is sufficient to keep animals out while allowing lint to exit freely.
Step 5: Reconnect and Test
Reattach the duct to the dryer, tighten the clamp, push the dryer back into position (don't crush the duct), and plug it back in.
Run the dryer on air-dry (no heat) for 5-10 minutes to blow out any remaining loose lint. Go outside and verify you can feel strong airflow coming from the exterior vent cap. If the airflow is weak, there may be a blockage you didn't reach... especially at bends in the duct.
When to Call a Professional
DIY cleaning handles most situations, but call a professional vent cleaning service ($100-$200) if:
- The vent run is longer than 25 feet or has more than 2 bends (the kit can't reach) - The vent goes through the roof (difficult and dangerous to access) - You can't feel airflow at the exterior after cleaning (there's a blockage you can't reach) - The duct is crushed, kinked, or made of plastic/foil accordion material (this should be replaced with rigid or semi-rigid metal duct)
A professional has commercial-grade equipment that can clean longer runs and uses a camera to verify the duct is clear.
Prevent Future Buildup
Clean the lint trap before every load. This alone prevents 75% of lint from entering the duct.
Clean the vent duct once a year... or twice a year if you do a lot of laundry (6+ loads per week).
Replace flexible plastic or foil accordion duct with rigid or semi-rigid aluminum duct. The smooth interior surface catches less lint, and rigid duct doesn't sag and create low spots where lint accumulates. The cost is $10-$30 for the duct plus 30 minutes to swap.
Keep the vent run as short and straight as possible. Every 90-degree bend is equivalent to adding 5-10 feet of straight duct in terms of airflow restriction.