Could a powered zone damper prevent leaks in a bathroom or kitchen exhaust?
Spring or gravity backdraft dampers prevent air from coming into a house through kitchen or bathroom exhaust ducts, but they can let air out when the exhaust fan is off. When air goes out through the backdraft damper, it’s letting air in somewhere else in the house. These dampers just make the exhaust duct a one way hole in the house instead of a two way hole.
The closing force on spring or gravity backdraft dampers must be minimized to reduce obstruction of air flow. Because fairly low forces are involved, the damper may get stuck open or closed when moisture, dust, or grease collect in the exhaust duct.
A powered damper would ensure that the damper only opens when the exhaust fan is running, and it greatly reduce the chance of a stuck damper. A Larson damper/fan combination is mentioned in some other questions on GBA. http://www.larsonfan.com/index.php?app=cms&ns=display&ref=Why
Are there any other powered dampers for exhaust ducts that aren’t blower/damper combos? Many different HVAC powered zone dampers and fresh air intake dampers are available. Could a powered zone damper like this Suncourt be used on a kitchen or bathroom exhaust?
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