What device should be installed at the open end of the dryer vent to prevent the intrusion of pests?

The correct choice is the damper, which plays a crucial role in preventing undesired elements from entering the dryer vent. A damper is a flap or valve that opens when the dryer is in operation, allowing moist air and lint to escape while closing off the vent when the dryer is not in use. This closure effectively keeps pests, such as rodents or insects, from entering the vent duct, which could pose a fire hazard or lead to clogs in the system.

Using a damper is essential for maintaining airflow and ensuring that the drying process is efficient. It also helps protect the integrity of your ventilation system, as stagnant air and debris can lead to a decrease in performance or even damage over time. A filter, while useful for trapping lint, does not provide the same level of protection against pest intrusion, as it does not seal off the vent when the dryer is not in use. Similarly, a dampener is typically used for adjusting airflow rather than providing a protective barrier, and a latch does not serve the specific function of preventing pest entry. Thus, the proper installation of a damper at the open end of a dryer vent is key to both functional efficiency and pest control.