How should an electric dryer vent terminate?

An electric dryer vent should terminate outside with a backdraft damper for several important reasons. First, allowing the vent to exit directly to the exterior ensures that moisture, lint, and any potential harmful gases are expelled from the interior of the home. This helps prevent the accumulation of lint and moisture, which can lead to mold growth, structural damage, and increased fire risks.

The inclusion of a backdraft damper is crucial because it prevents outside air from entering the vent when the dryer is not in operation. Without this damper, cold air can infiltrate into the ductwork, potentially leading to condensation build-up, which can also contribute to moisture-related issues. Moreover, the damper protects against pests and debris entering the vent system, ensuring that the airflow is not obstructed when the dryer is in use.

In contrast, terminating the vent inside the building or with a filter does not effectively manage the released moisture and lint, creating hazardous conditions. This could lead to indoor air quality issues or increase the likelihood of dryer fires due to lint build-up within the ductwork. Therefore, terminating the dryer vent outside with a backdraft damper is the preferred and safest practice.