Deflecto Dryer Vent Draft Blocker, 4-Inch Inline Backdraft Damper, White

Keep unwanted outdoor air where it belongs with the Deflecto 4-Inch Dryer Vent Draft Blocker BD04. With its 4‑inch diameter opening, this draft blocker connects securely to standard 4-inch diameter dryer ducts, bathroom exhaust fans, and residential venting systems. Measuring 5” wide by 5” high with 2.5"" depth, it installs inline between vent pipe and exterior hood, making it versatile for multiple applications. The heart of the design is a gravity‑balanced damper flap that responds instantly to airflow. When your dryer or exhaust fan is running, the flap opens to allow air to pass freely. Once the appliance is off, the flap closes automatically, creating a one‑way seal that limits drafts and keeps outdoor debris from entering into your home through your vent. This simple maintenance-friendly design provides steady one-way airflow operation without complicated components. Constructed from durable calcium-filled polypropylene, this vent draft blocker is designed for dryer vent applications and everyday residential use. The lightweight plastic construction makes it rust-resistant while standing up to heat commonly found in venting systems. Its compact profile also allows installation in areas with limited space. The unit arrives fully assembled and ready for installation. Compatible with a variety of installation methods for flexible and rigid duct systems, allowing you to choose the clamps, adhesive, or sealant appropriate for your vent configuration. Mounting hardware not included.

• FITS STANDARD 4-INCH DUCTS: Built with 4‑inch diameter opening to connect securely with dryer ducts, bathroom exhaust fans, and residential venting systems. Measures 5” wide by 5” high with 2.5" depth, allowing inline installation between ductwork and exterior hood for versatile draft‑blocking applications.
• AUTOMATIC BACKDRAFT DAMPER: This gravity-balanced backdraft damper functions as a draft blocker for dryer vent, opening when the dryer or exhaust fan is operating and closing when airflow stops to promote one-way airflow. It helps lessen cold air infiltration while limiting drafts, dust, and outdoor debris from entering through the vent.
• VERSATILE VENTING APPLICATIONS: Ideal as a dryer vent damper, backflow preventer and bathroom exhaust fan draft blocker, for laundry rooms, utility spaces, bathroom exhaust fans, and other residential ventilation systems.
• EASY INSTALLATION: Designed for straightforward installation in standard 4-inch dryer duct and exhaust vent systems. This dryer vent damper arrives fully assembled and functions as a backdraft damper for residential ductwork. Mounting hardware not included.
• HEAVY-DUTY PLASTIC CONSTRUCTION: Made from calcium-filled polypropylene designed for dryer vent applications. The lightweight 4-inch backdraft damper's rust-resistant material withstands heat while providing steady performance for everyday residential use.