Bi Metal Vent Damper

Bi metal vent dampers were very popular from the 1970-1980’s as a means of conserving energy. The theory is that the bi metal fingers will open from the heat and allow the gases to exhaust and close when cooled to reduce lose of conditioned air from the interior. They are supposed to fail in the open position, but we have found numerous cases where this has not occurred. We recommend that they be removed from both hot water heater vents and furnaces as a safety precaution.