What should NOT be installed at the termination of a clothes dryer exhaust duct?

The correct answer is that a screen should not be installed at the termination of a clothes dryer exhaust duct. A screen can trap lint and debris, which poses significant fire hazards as these materials can accumulate and block airflow. This blockage can cause the dryer to overheat or malfunction, potentially leading to fires. Additionally, a screen can impede the efficient expulsion of moist air from the dryer, which is essential for effective drying and preventing moisture buildup in the home.

On the other hand, flap mechanisms and vent caps are designed to facilitate the safe exit of air while keeping pests and debris from entering the duct system. Duct tape, while it might initially seem like a possible option, is not a good long-term solution due to its durability issues in high-heat scenarios, therefore it's not recommended for securing dryer ducts.