what is a ventilation damper
A vent damper is an automatic devise that shuts off the flue pipe when the burner is not running. A vent damper has no effect on the running efficiency of the appliance. It only saves off-cycle losses of heated air. Therefore, if the appliance is in an unheated space, there is no benefit to a vent damper. A vent damper can achieve up to 10% annual fuel savings.