Homeowner checklist
Dryer vent warning signs
Updated November 2026. Each sign links to the agency that names it.
The clearest sign of a clogged dryer vent is clothes that are still damp after a normal cycle.[1] Next, run the dryer and check that the outdoor flap opens and air is coming out. If either check fails, clean the vent before your next load. Failure to clean is the leading factor in home dryer fires.[6]
Signs you notice while doing laundry
Clothes are still damp after a normal cycle
The CPSC says damp clothing at the end of a typical cycle, or drying that takes longer than normal, may be a sign that the lint screen or the exhaust duct is blocked.[1]
What to do: Clean the lint screen first. If drying is still slow, the vent itself likely needs cleaning.
Drying takes longer than it used to
NFPA advises cleaning lint out of the vent pipe once a year, or more often if you notice it is taking longer than normal for your clothes to dry.[2]
What to do: Treat a slower dryer as a cleaning reminder, not just an annoyance.
Signs at the outdoor vent
The outdoor flap does not open, or no air comes out
With the dryer running, check the outside vent. The CPSC says if exhaust air is not escaping, the vent or exhaust duct may be blocked. NFPA and the U.S. Fire Administration also say to make sure the outdoor vent flap opens while the dryer operates.[1][2][3]
What to do: Clear what you can safely reach at the hood. The CPSC notes that removing a blockage may require disconnecting the duct from the dryer; reconnect it before you run the dryer again.
A bird or animal nest in the vent
The U.S. Fire Administration notes that dryer exhaust vents can be blocked by the nests of small birds or other animals, and a compromised vent will not exhaust properly, which can lead to overheating and fire.[4]
What to do: Do not run the dryer until the nest is removed and the hood closes properly.
A screen over the vent opening
Screens trap lint. Florida's residential code, adopted from the International Residential Code, says screens shall not be installed at the dryer duct termination and requires a backdraft damper instead.[5]
What to do: Replace a screened cover with a proper dryer vent hood that has a backdraft damper.
Signs in the duct behind the dryer
Plastic or foil accordion duct
The CPSC recommends replacing plastic or foil accordion-type duct with rigid or corrugated semi-rigid metal duct. Flexible plastic or foil duct can more easily trap lint and is more likely to kink or crush, which can greatly reduce airflow.[1]
What to do: Swap it for metal duct. Most dryer manufacturers specify metal.
Crushed, kinked or disconnected duct
The U.S. Fire Administration says to check the venting system behind the dryer to make sure it is not damaged, crushed or restricted.[3]
What to do: Leave a few inches behind the dryer so the duct is not pinched against the wall.
A vent that ends indoors, in the attic or in a crawl space
Florida's residential code requires dryer exhaust ducts to terminate on the outside of the building and says exhaust air shall not be discharged into an attic, soffit, ridge vent or crawl space.[5]
What to do: Have the duct rerouted to an exterior termination. This is an installation fix, not a cleaning job.
A 10-minute vent check
- Clean the lint filter and wipe out lint around the drum.[2]
- Start a load, go outside, and confirm the vent flap opens and exhaust air is escaping.[1]
- Unplug the dryer, pull it out, and check the duct for foil or plastic, kinks, crushing or gaps.[3]
- Note how long a normal load takes. If it is still damp after a typical cycle, book a cleaning.
Want it on paper? Print the free dryer safety checklist. For the numbers behind these warnings, see dryer fire statistics.
When to call a professional
Call a pro if the outdoor flap does not open, the duct runs through walls or the roof, there is a nest, or drying is still slow after you clean the lint filter. The Chimney Safety Institute of America certifies dryer vent technicians through its CDET credential.[7] Read what CDET means, how to choose a cleaner and what a cleaning costs, or start with the top rated pros in your city.
Source note: code references come from the Florida Building Code, Residential, 8th Edition (2023), Section M1502 Clothes Dryer Exhaust (adopts the 2021 International Residential Code with amendments). Your city may enforce a different edition or local amendments.
Frequently asked questions
What are the signs of a clogged dryer vent?
The most common signs are clothes that are still damp after a normal cycle, drying that takes longer than it used to, and an outdoor vent flap that does not open or blows little air while the dryer runs. The CPSC and NFPA both name slow drying as a sign the lint screen or exhaust duct may be blocked.
Is foil or plastic dryer duct safe?
The CPSC recommends replacing plastic or foil accordion-type duct with rigid or corrugated semi-rigid metal duct, because flexible plastic or foil duct traps lint more easily and is more likely to kink or crush.
Can a dryer vent end in the attic?
No. Florida's residential code, based on the International Residential Code, requires dryer exhaust ducts to terminate outside the building and does not allow exhaust into an attic, soffit, ridge vent or crawl space. Check the code your city enforces, but an indoor termination is a red flag.
Can a bird nest block a dryer vent?
Yes. The U.S. Fire Administration notes that nests of small birds or other animals can block dryer exhaust vents, and a vent that cannot exhaust properly can overheat and start a fire.
How often should a dryer vent be cleaned?
NFPA recommends cleaning lint out of the vent pipe once a year, or more often if drying takes longer than normal. Clean the lint filter before or after every load.
Need a dryer vent cleaned?
Seeing one of these signs? Pick your city and send one free request to local dryer vent pros.
Run a dryer vent business?
Listings are free. Featured pros appear first in their city and get homeowner quote requests first. First month free, then $19/month.
Sources
- U.S. Consumer Product Safety Commission, “Overheated Clothes Dryers Can Cause Fires, Publication 5022,” revised February 2012.
- NFPA, “Clothes Dryer Safety tip sheet,” 2018 edition.
- U.S. Fire Administration (FEMA), “Clothes Dryer Fire Safety flyer,” accessed 2026.
- U.S. Fire Administration (FEMA), “Clothes Dryer Fires in Residential Buildings (2008-2010), Topical Fire Report Series Vol. 13, Issue 7,” published August 2012, NFIRS data 2008-2010.
- Florida Building Code, “Residential, 8th Edition (2023), Section M1502 Clothes Dryer Exhaust (adopts the 2021 International Residential Code with amendments),” read on UpCodes, 2026.
- NFPA (National Fire Protection Association), “Home Dryer Fires, Marty Ahrens,” published June 2020, 2014-2018 annual averages.
- Chimney Safety Institute of America (CSIA), “Certified Dryer Exhaust Technician (CDET),” accessed 2026.