An Often-Overlooked Cleaning Task: Your Dryer Ductwork and Vent

Cleaning dryer ventsYour clothes dryer has a filter to catch lint as clothing tumbles inside, but the filter cannot catch it all. Some inevitably passes into the ductwork leading to the outdoor vent. Proper maintenance requires that this ductwork and vent be cleaned regularly.

It is crucial that your dryer ductwork is cleaned. The US Fire Administration reports that more than 2,900 home fires are started by clothes dryers every year. The leading cause of these fires is a buildup of lint.

Lint is made up of small particles of cloth and fiber, dirt, pet hair, and dander that is loosened from laundry by the agitating water during the wash and rinse cycles. Lint gets trapped in the crevices deep inside the lint filter trap- and all along the dryer ductwork as it makes it way to the outside vent opening. Lint build-up restricts airflow and can lead to overheating, which can ignite the lint.

Warning signs of lint buildup include:

  • Clothes take longer to dry or don’t fully dry
  • Clothes are hotter than usual at the end of the drying cycle
  • The outside of the dryer gets very hot
  • Outside exhaust vent flapper doesn’t open as it should
  • The laundry room gets very humid during the drying cycle
  • There is a burning smell in the laundry room

DIY Dryer Ductwork and Vent Cleaning

To do the job right, you will need the following tools:

  • Vacuum with a long hose attachment
  • Dryer vent brush kit
  • Screwdrivers
  • UL-listed metal foil duct tape

Thorough dryer vent cleaning requires special brushes. Vacuum attachments alone do not work as well because they do not agitate the lint to remove it from the walls of the duct, and they can’t reach deep enough inside the dryer’s lint filter housing. A brush kit comes with a long-bristle brush to clean the lint filter area and a round-bristled brush that can clean out a four-inch round rigid dryer duct. The brush tip fastens to a flexible fiberglass shaft that can be lengthened in sections.

Step-by-Step Instructions

Remove and clean the lint trap filter.

Vacuum the lint trap housing using a long, skinny hose attachment.  Clean it again using the long flexible brush from the brush kit, extending the brush all the way into the bottom of the cavity. Gently twisting the brush, pulling it out to extract clumps of lint. Clean the brush bristles with the vacuum and reinsert the brush into the lint trap housing until no more lint can be removed.

Disconnect the dryer ductwork. Unplug the dryer’s power cord and turn off the gas valve at the dryer. Disconnect the duct joint closest to the dryer and gently p0ull the dryer away from the wall. Disconnect the remaining exposed sections of dryer duct. If the sections are taped, remove and discard the tape.

Vacuum the Ductwork.
Attach the round duct brush head to the flexible fiberglass shaft, following the instructions that come with your brush kit. Insert the brush into each duct section and sweep it clean using a rotating motion, while moving the brush back and forth. Pull out the brush and clean the head frequently. 
Clean the rest of the duct using the same techniques, adding more sections of the flexible shaft, as needed, to reach the end of the rigid duct. Repeat until no more lint is removed.

Clean the Vent Cap. Check the vent cap at the exterior end of the duct to make sure it is clean, and its flapper door works properly.

Note: Some brush kits can be connected to a portable drill to spin the brush inside the duct. If you use this option, run the drill at slow speed and advance the brush gradually through the duct.

Safety Considerations

The flexible plastic or metal foil ductwork that was once commonly used to connect dryers to outside vents are now prohibited by most building codes. These vent tubes were popular because of the ease with which they can be routed through difficult spaces, but their inside surfaces are ribbed, so they can easily catch lint and cause fires due to overheating.

If you have one of these flexible ducts installed, it is best to replace it with smooth-walled metal ductwork. If you can’t remove and replace it, the ductwork should be regularly removed and carefully cleaned out from one end to the other.

If you have questions about dryer vent cleaning, call one of our technicians at Nashoba Air & BoilerWorks at 855.465.0600.