Dryers Extract Lint

• As clothes tumble in a dryer, hot, dry air flows through the load to quickly evaporate and evacuate the removed water droplets. Tiny fibers that are loose, loosened by the washing machine's actions or poorly attached to the clothes detach from the garment and blow around the tub and its contents. These fibers, known as lint, collect on the clothes and the tub and must evacuate through small holes in the tub.
  
  

Dryers Evacuate Lint

• Manufacturers design dryers to catch the lint and evacuate it through the dryer's air vents; as air blows through the tub, it collects the lint and carries it through the holes to exit the dryer. On most modern models, a lint trap, sometimes known as a lint filter, collects the lint and prevents it from exiting through the dryer's air vents. Some lint fibers escape through the filter, though, and exit through the dryer's pipes and into the air vent.
  
  

Vent Blockages May Cause Lint Buildup

• When lint fibers pass through the lint trap or filter and exit into the air vent, the dryer's design allows it to use the exiting hot air to carry the lint through the vents and exit into the environment (where it naturally decomposes). In some cases, though, a blockage in the air vents may impede the flow of air or a hole in the vent work may divert the flow into surrounding areas. If a blockage impedes the flow of air through the dryer vents, the air must find another way to exit and often escapes through joints in the vent work; as the air escapes, it carries the lint fibers with it, allowing the fibers to collect around the joint where the air escapes. According to Dryer Vent Wizard, a dryer service company, lint buildup accompanied by reduced ability of the dryer to dry clothes is very likely a sign of blockage in the vent that must be cleared to resolve the issue.
  
  

Vent Holes Also Allow Buildup

• In some cases, exiting lint may build up even if no blockage exists in the dryer vents. If the air exiting the dryer encounters a hole in the vent work, it may escape through the hole rather than completing its journey to the outside environment. As the air exits through the hole, it carries its lint payload, which then collects around the hole. The website for Swede Sweep, a dryer vent installation company, recommends using solid metal pipes for dryer vents to prevent holes, as more flexible foil or plastic vent work may crush or tear to allow air and lint to exit the vent.