How to clean a dryer vent

Clean the lint screen every load and the vent duct at least once a year, because failure to clean is the leading cause of home dryer fires.

Man pouring liquid detergent into a stacked washer and dryer in a modern laundry room. — Photo: RDNE Stock project / Pexels

Area: HomeFrom age 18Time to learn: 5 minutes for the lint screen; about an hour for the first full vent cleaning

Clean the lint screen before or after every load, and clean the duct and outside vent at least once a year, or sooner if clothes start taking longer to dry.

SafetyUnplug the dryer before you touch the duct, and on a gas dryer turn off the gas supply first. If you smell gas, do not touch any switch: leave the house and call your gas company or 911 from outside. NFPA advises having a gas dryer inspected by a qualified professional to make sure the gas line and connection are intact and free of leaks, and Toronto Fire Services advises a carbon monoxide alarm in any home with a natural gas or propane dryer. If the duct runs through a wall, ceiling or roof you cannot reach, hire a certified dryer exhaust technician (the Chimney Safety Institute of America certifies them) rather than forcing a brush through it.

Why it matters

Lint is fine, dry fiber that catches fire easily, and a dryer pushes hot air past it every cycle. NFPA research found that failure to clean is the leading cause of home dryer and washer fires, and that dust, fiber or lint is the item most often first ignited in dryer fires. A clear vent also dries clothes faster, so the machine runs for less time.

From 2010 to 2014, US fire departments responded to an estimated 15,970 home fires a year involving clothes dryers or washing machines. Dryers were involved in 92 percent of them, and the leading cause, at 31 percent, was failure to clean.

Source: National Fire Protection Association, Home Fires Involving Clothes Dryers and Washing Machines, 2017.Measured

How to do it

Clean the lint screen before or after every load. Pull it out, roll the lint off with your fingers, and push the screen fully back into its slot. Never run the dryer without the screen in place.
Scrub the screen with a soft nylon brush at least every 6 months, or sooner if it looks clogged. Wash it in warm soapy water, rinse it, and let it dry completely before you put it back.
Clean the duct once a year, or sooner if a normal load needs more than one cycle. Unplug the dryer first. On a gas dryer, also turn off the gas supply valve, and move the dryer gently so you do not kink or strain the gas line.
Pull the dryer out far enough to reach the back. Loosen the clamp and slide the duct off the dryer's exhaust outlet.
Clean the duct from both ends. Vacuum each end, then push a dryer-vent brush through the whole run, adding extension rods until the brush comes out the far end. If you spin the brush with a drill, follow the kit's instructions. Most say to turn it clockwise only, at low speed, with the rod joints tightened and taped, because turning it backward can unscrew a rod and leave the brush stuck in the duct.
Go outside to the vent hood. Pull lint off the flap, clear out any nest, leaves or snow, and check that the flap swings freely. Do not fit wire screen or cloth over the opening, because it traps lint.
Vacuum the dryer's exhaust outlet and the floor behind and under the dryer, where lint builds up.
Inspect the duct. If it is white plastic or thin coiled foil, or is crushed or torn, replace it with rigid metal duct. In the US, residential codes based on the International Residential Code require the flexible connector between dryer and wall, called the transition duct, to be a single length listed to UL 2158A, no longer than 8 feet (2.4 m), and never hidden inside a wall or ceiling. In Canada, follow the dryer maker's installation instructions and your local code.
Reconnect the duct and tighten the clamp. Push the dryer back without crushing the duct, plug it in, and turn the gas back on if you turned it off. Run the dryer empty and check outside that the air pushes the flap open.

Common mistakes

Cleaning only the screen. Lint still collects in the duct and behind the machine, so the duct needs its own yearly cleaning.
Using plastic or foil duct. It kinks, sags and gets crushed, which traps lint, and plastic can melt and burn.
Ignoring slow drying. If towels or jeans take longer than usual, or clothes come out hotter than normal, the vent is probably clogged.
Leaving the dryer running when you leave home or go to bed.

You can do this when …you clean the screen every load without being reminded, can take the duct off and put it back with the clamp tight, and have stood outside to watch the flap open while the dryer runs.