Actually, there is a way to have multiple dampers installed.
This is beneficial if someone is attempting to trap the cold air column within the chimney.
Sometimes, when using only a top mounted damper, there is still a significant cold air effect present and shutting the primary damper will stop of slow down this effect.
Is this a common practice? If so, on masonry or metal chimneys or both? Are there any studies or research to show its actual effectiveness?
Just Curious,
Aaron
