<P> A clean, unobstructed dryer vent improves the safety and efficiency of the dryer . As the dryer duct pipe becomes partially obstructed and filled with lint, drying time increases and causes the dryer to overheat and waste energy . In extreme cases, a blocked vent may result in a fire . Clothes dryers are one of the more costly home appliances to operate . </P> <P> Several factors can contribute to or accelerate rapid lint build - up . These include long or restrictive ducts, bird or rodent nests in the termination, crushed or kinked flex transition hose, terminations with screen - like features, and condensation within the duct due to un-insulated ducts traveling through cold spaces, such as a crawl space or attic . </P> <P> Dryers expose flammable materials to heat . Underwriters Laboratories recommends cleaning the lint filter after every cycle for safety and energy efficiency, provision of adequate ventilation, and cleaning of the duct at regular intervals . UL also recommends that dryers not be used for glass fiber, rubber, foam or plastic items, or any item that has had a flammable substance spilled on it . </P> <P> In the United States, the U.S. Fire Administration in a 2012 report estimated that from 2008 to 2010, fire departments responded to an estimated 2,900 clothes dryer fires in residential buildings each year across the nation . These fires resulted in an annual average loss of 5 deaths, 100 injuries, and $35 million in property loss . The Fire Administration attributes "Failure to clean" (34%) as the leading factor contributing to clothes dryer fires in residential buildings, and observed that new home construction trends place clothes dryers and washing machines in more hazardous locations away from outside walls, such as in bedrooms, second - floor hallways, bathrooms, and kitchens . </P>

Where does the water go in a tumble dryer