Does a manual pipe damper hold heat in a stove?
This came up on another thread and thought it deserves a thread of its own. To me, It's a matter of perspective. Is the glass half full or is it half empty?
I think everyone could agree that in order for heat to be lost up a chimney, it needs a vehicle to catch a ride on. In this case, That vehicle would be excess air. Air in equals air out. Let's consider two scenarios. A tight well sealed stove and a leaky not so well sealed stove.
With the well sealed stove (with independent primary and secondary controllable combustion air) the manual damper weakens or strengthens the negative pressure in the fire box. This pressure dictates how much volume of combustion air enters the stove and effectively controls the burn rate. I can slow the burn rate which makes the fire box cooler by closing the manual damper which is exactly what I see happen.
Now for the leaky stove with fixed secondary combustion air. With excessive air (manual damper open), heat is carried up and out the chimney and also this excessive air can have a cooling effect on the fire box. With manual damper closed, the excessive air coming in is limited so those ill side effects are lessened.
So, in a technical aspect does the manual damper "hold heat in the stove"? In my opinion, not really... It limits air in by limiting air out. That's just my perspective.