Dryer Vent Cleaning: How to Remove Lint and Prevent Fires

Quick Answer

Cleaning a dryer vent involves removing lint buildup from the ductwork connecting the appliance to the exterior wall. The primary fix is using a vacuum or specialized brush kit to clear the entire length of the vent.

A clogged dryer vent is the number one cause of house fires from laundry appliances. Ignore it long enough and your dryer starts overheating, your clothes take two cycles to dry, and eventually something ignites. I've seen it happen. Clean this thing at least once a year, more if you've got a big family or wash a lot of towels and blankets.

GenericDryerSeverity: moderateDifficulty: intermediate75% DIY Success

Time to Fix

15–90 min

Difficulty

intermediate

Parts Cost

—

Tools Needed

Dryer vent brush kit with flexible rods (at least 12 feet worth), Shop vacuum or strong household vacuum with crevice tool

What Does the HOW-CLEAN-VENT Code Mean?

This is one of those maintenance jobs that takes maybe 45 minutes and a $20 brush kit, but people skip it for years until their dryer dies or worse. Your vent duct is a tunnel from the back of your dryer all the way to the outside wall, and lint packs into it a little bit every single load. Most folks clean the lint screen and call it done, but that screen only catches maybe 60-70% of the lint. The rest goes into the duct.

Common Causes

Lint packed into the duct over years of use, especially near the elbows where airflow slows down and the stuff just sticks to the walls and builds up layer by layer.
The lint screen only catches the bigger stuff, so fine fibers from microfiber towels, fleece, and pet bedding pass right through it and coat the inside of the ductwork.
Crushed or kinked flexible duct behind the dryer, usually because somebody pushed the machine too close to the wall and folded the hose.
A bird or small animal built a nest in your exterior vent cap. Happens constantly in spring. I pulled a full robin's nest out of a vent cap last April and the homeowner had no idea why their dryer was taking forever.
The duct run is too long or has too many 90-degree elbows. Every elbow adds resistance equivalent to about 5 feet of straight duct, and most manufacturers max out around 25 feet total equivalent length.
Plastic or foil accordion flex hose instead of rigid metal duct. That ribbed interior surface catches lint like velcro and you can never fully clean it out. If you've got that stuff, replace it.

Symptoms You May Notice

Clothes are still damp after a full normal-length cycle and you're running it twice to finish the job.
The dryer exterior or the area around the exhaust gets noticeably hot, and the laundry room feels humid while it's running.
A burning or hot dust smell coming from the dryer or from outside near the vent cap.
The outside vent flap barely opens or stays shut entirely when you check it during a cycle.
Drying times have slowly gotten worse over the past several months and you can't pinpoint when it started.

Can you reset a Generic dryer to clear the HOW-CLEAN-VENT code?

There's no error code to reset here since this is a maintenance procedure, not a fault code. After cleaning, just plug the dryer back in, turn on the gas if it's a gas unit, and run a test cycle. If your dryer was showing an actual error code related to overheating before you cleaned the vent, unplug it for 5 full minutes to let the thermal sensors reset, then plug it back in and try a cycle.

Tools Required for Diagnosis

Dryer vent brush kit with flexible rods (at least 12 feet worth)Shop vacuum or strong household vacuum with crevice toolPhillips #2 screwdriverFlathead screwdriverFlashlight or headlampWork glovesDust maskPliers (for hose clamps if present)

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Frequently Asked Questions

How often should I clean my dryer vent?

Once a year minimum for an average household. If you've got a big family doing 10+ loads a week, pets that shed a lot, or you wash a ton of towels and blankets, bump it up to every 6 months. The other thing that matters is duct length. A short straight run stays cleaner longer than a 30-foot run with three elbows. Basically, if your drying times are creeping up, don't wait for the annual cleaning date.

Can I clean it myself or do I need a professional?

You can absolutely do it yourself. A $20 brush kit from the hardware store handles 90% of residential vent runs. The only times I'd say call a pro are if your duct runs through the attic or a wall cavity with no access, if it's over 25 feet long, or if you found evidence of a fire in there like scorching or melted material. Duct cleaning services run $80-150 and they've got vacuum equipment that does a thorough job. Worth it once every few years even if you DIY in between.

What happens if I just don't clean it?

Short term, your clothes take way longer to dry and your energy bill goes up. Your dryer works harder than it needs to and wears out faster. Long term, the thermal fuse trips and the dryer stops heating entirely, which is a $20-40 part but annoying to replace. And worst case, the lint in the duct catches fire. Around 15,000 house fires a year in the US are attributed to dryers, and the vast majority of those are clogged vents. It's not a theoretical risk.

My dryer takes two cycles to dry clothes. Is that the vent?

Probably, yeah. Restricted airflow is the most common reason for long dry times, especially if it got worse gradually over time. But it could also be a worn drum seal letting air bypass the clothes, a heating element that's partially failed, or a clogged moisture sensor. Clean the vent first since it's free and easy. If drying times are still bad after that, clean the moisture sensor strip inside the drum with a cotton ball and rubbing alcohol. After those two things, if it's still slow, you're looking at a heating component issue.

Is flexible plastic duct OK or do I need rigid metal?

Rigid metal is way better and honestly most building codes require it now. The plastic accordion stuff has ridges on the inside that catch lint constantly, you can't fully clean it, and it can sag and trap moisture. Semi-rigid aluminum duct is the minimum you should use for the connection behind the dryer. For runs inside walls or the attic, it needs to be smooth-wall rigid metal. If you've got the old white plastic flex hose, do yourself a favor and replace it when you do your next cleaning. The whole thing costs like $15.

What's the exterior vent cap supposed to look like?

It should be a metal or plastic housing with a flap or louvers that open when there's airflow and close when there isn't. The flap should move freely with just a light touch. There should be no screen on the interior side since screens catch lint and clog fast. A lot of older homes have screened caps and that's a problem. Replace them with a louvered style that's open inside. Also make sure the cap is pointed down or sideways, not up, so rain can't get in.

Written by

Mike Sullivan

Lead Appliance Repair Technician · 20 years experience

Last verified for technical accuracy on March 17, 2026