What is a potential issue if a clothes dryer duct terminates within 3 feet of a door or window?

The termination of a clothes dryer duct within 3 feet of a door or window presents the risk of dryer exhaust gases returning back into the house. This issue arises because the exhaust stream, which can carry moisture, lint, and potentially harmful gases, might be blown back inside by the wind or air movement caused by the opening and closing of the door or window. Such a situation can lead to poor indoor air quality and create a hazardous environment, as these gases can include carbon monoxide and other contaminants.

Other potential issues such as increased energy consumption or noise disturbance are less directly related to the specific concerns of duct termination in this context. While reduced drying efficiency could result from improper venting, the most significant and immediate risk linked to terminating the duct too close to an opening is the possibility of exhaust re-entering the living space.