Dryer lint? Clear it every load.

Why agencies treat dryer lint as a fire problem

CPSC’s dryer-fire safety alert says fires can occur when lint builds up in the dryer or in the exhaust duct: lint can block airflow, cause excessive heat build-up, and result in a fire in some dryers. NFPA’s tip sheet states the leading cause of home clothes dryer fires is failure to clean them. USFA/FEMA’s flyer puts the risk in one line: you are at higher risk of a clothes dryer fire if you do not clean your lint filter and dryer vents. [S1] [S3] [S4]

Seattle Fire’s 2024 client memo repeats the same cleaning habits and notes dryer-fire incidence figures attributed to NFPA. Those numbers are background for why fire departments care; they are not a forecast for any one house. The habit this guide keeps is the shared prevention list, not a statistics stack. [S7]

Clear the lint filter every load

CPSC says to clean the lint screen/filter before or after drying each load of clothes. NFPA matches that cadence: clean the lint filter before or after each load, remove lint that collected around the drum, and do not use the dryer without a lint filter. USFA/FEMA says do not use the dryer without a lint filter and to clean the lint filter before and after each cycle, and not to forget the back of the dryer where lint can build up. One dryer maker’s consumer how-to recommends cleaning the lint filter after each use and, if fabric softener is used, washing the filter periodically in warm soapy water. It’s cited here as an example of maker wording, not a brand pick. [S1] [S3] [S4] [S8]

CPSC also flags a practical warning sign: if clothing is still damp at the end of a typical drying cycle, or drying takes longer than normal, that may mean the lint screen or the exhaust duct is blocked. Treat longer dry times as a reason to clear the filter and check the vent path before running another load. [S1]

Where the sources pull in different directions. Filter timing: CPSC and NFPA say before or after each load; USFA/FEMA says before and after each cycle. We treat every load as the non-negotiable minimum and treat “before and after” as the stricter reading of the same habit. Duct wording: CPSC says replace plastic or foil accordion-type ducting with rigid or corrugated semi-rigid metal; NFPA says rigid or flexible metal venting; DOE’s weatherization job aid specifies rigid or semi-rigid metal, outdoors termination, a backdraft damper, and no cage/grille/screen on the termination. We keep CPSC’s metal-not-plastic/foil accordion rule as the homeowner takeaway and DOE’s no-screen termination as the outdoor-cap detail. Vent cleaning interval: NFPA, Seattle Fire and PNNL point to about once a year, or sooner when drying takes longer. We stay with that annual-or-sooner line and tell readers to follow their own manual when it is stricter. [S1] [S3] [S4] [S5] [S6]

Check the outdoor vent while the dryer runs

CPSC says to clean the dryer vent and exhaust duct periodically, and to check the outside dryer vent while the dryer is operating to make sure exhaust air is escaping. If it is not, the vent or exhaust duct may be blocked; clearing a blockage may mean disconnecting the exhaust duct from the dryer, and CPSC reminds you to reconnect the ducting to the dryer and outside vent before using the dryer again. NFPA says make sure the air exhaust vent pipe is not restricted and the outdoor vent flap will open when the dryer is operating, and to clean lint out of the vent pipe once a year, or sooner if clothes take longer than normal to dry, or to hire a dryer lint removal service. USFA/FEMA adds: check the venting system behind the dryer for damage, crushing or restriction, and make sure the outdoor vent covering opens when the dryer is operating. [S1] [S3] [S4]

PNNL’s Building America guide says the duct should vent to the outside, not into an attic or crawlspace, and that the outdoor cap should be a single flap or a louvered flap without a screen, because screens trap lint and block airflow. DOE’s job aid makes the same outdoor-termination and no-cage/screen points and notes that long runs or excessive bends create a fire hazard and increase dry time. NFPA also says to make sure the outdoor vent flap is not covered by snow. [S6] [S5] [S3]

These branches summarize agency and lab guidance. They are not a fire inspection of your laundry room.

Keep the path clear, plus a few rules while you dry

Beyond the filter and outdoor flap, the sources share a short operating list: have the dryer installed and serviced by a professional; keep the area around the dryer clear of things that can burn; do not overload; follow the maker’s instructions; turn the dryer off if you leave home or go to bed; and take special care with clothes soiled with gasoline, cooking oils, cleaning agents, finishing oils or similar solvents. CPSC prefers washing more than once and hanging to dry when possible, and if a dryer is used, the lowest heat setting with a cool-down period, without leaving dried clothes in the dryer or piled in a basket. NFPA and Seattle Fire say clothes that contacted flammable substances should be laid outside to dry, then washed and dried as usual. [S1] [S3] [S7]

Before the next laundry day