The once-a-year rule and where it comes from
NFPA’s clothes dryer safety tips say to clean lint out of the vent pipe once a year, or more often if you notice clothes taking longer than normal to dry, or to have a dryer lint removal service do it for you. The U.S. Fire Administration gives similar advice: have the dryer’s venting system cleaned periodically, especially if drying is taking longer than normal.
The reason is fire. The U.S. Fire Administration estimates 2,900 clothes dryer fires in residential buildings are reported each year, and failure to clean was the leading factor behind them, at 34%. Those numbers come from 2008–2010 data, the most recent in that report.
When to clean sooner than once a year
A year is the baseline, not a promise. Some vents clog faster than others:
- Long runs, or runs with several turns. The U.S. Fire Administration notes that moisture condenses in long, bendy vents and attracts lint.
- Laundry rooms upstairs or in the middle of the house, which often need a longer vent to reach an outside wall.
- Plastic or foil accordion hose behind the dryer, which CPSC says traps lint more easily and kinks or crushes.
- A flap that sticks, or birds and nesting material at the outside hood.
- Clothes that take more than one cycle, or come out hotter than usual.
Apartments, condos and townhomes
Shared buildings aren’t exempt. The U.S. Fire Administration found 17.4% of residential clothes dryer fires happened in multifamily dwellings (2008–2010 data). Long interior runs can make those vents harder to reach and easier to forget.
If you rent or live in a condo, ask your landlord or association who handles dryer vent cleaning and when it was last done. The same warning signs and the same once-a-year baseline apply.
What to do between cleanings
Clean the lint filter before or after every load, and never run the dryer without one. NFPA and CPSC both put this first.
Every so often, run the dryer and step outside to make sure the flap opens and air is blowing out. Keep the area around the dryer clear of boxes, cleaning supplies and clothes, and don’t leave the dryer running when you leave home or go to bed, as NFPA advises.