Dryer Emissions

• A clothes dryer discharges a significant amount of warm, moist air from the drum while tumbling clothes dry. The emissions are released through the dryer's exhaust system, which starts at the vent collar, continues through the ducting and ends at the external vent. On the way to the external vent, moisture tends to linger in the ducting and sometimes collects on its walls. Although the moisture normally dries up after the drying cycle ends, in certain cases it remains there and attracts lint. When lint combines with moisture it develops into a tacky residue that diminishes airflow in the ducting. If air circulation is constrained, moisture that collects in the exhaust might eventually drip into the drum after the dryer stops running.
  
  

Clean the Exhaust System

• One of the first things to do when you find moisture in the drum is to clean the exhaust system. Start by emptying the dryer's lint screen. If the screen is full, it's a sign that there might be a block in the exhaust system. Review your dryer's user guide for directions on how to clean the exhaust system. It might recommend that you purchase a cleaning kit or special tools, which you can usually find at a home improvement store or appliance retailer. You can prevent clogs from developing by making a habit of emptying the dryer's lint screen after each laundry load is done. Also, clean the dryer's exhaust system about once every two years, and more often if you use your dryer a lot.
  
  

Modify the Exhaust System

• If cleaning your dryer's exhaust system didn't rid your dryer of moisture, the next thing you want to do is inspect your ducting for possible defects. Moisture is more likely to form on certain ducting materials more so than others. For example, moisture develops quicker in plastic ducting, especially with ribbing than heavy-duty, non-ribbed metal ducting. Air circulates better and more freely in ducting with a smooth surface; a ribbed surface ribbing draws moisture and lint. Switch out plastic ducting for metal, and replace ribbed sections with non-ribbed ones.
  
  

Considerations

• Measure the length of the dryer's ducting. The ducting shouldn't be longer than 25 feet, and it's even better if the ducting's length is shorter. If the ducting is close to 25 feet or longer, look for ways to shorten it. If you're unable to shorten it, add a blower fan at about 15 feet of the way through the ducting to enhance air circulation and reduce condensation. Furthermore, the straighter and more horizontal the ductwork, the less likely that condensation will collect inside, and eventually end up back in your dryer. Eliminate needless elbows or bends in the ducting.