Masonry FP ..glass doors?
I've got a masonry fireplace with an outside combustion air vent into the firebox.
I thought, I'd like to add a "glass door fire screen" to save some of the inside air from going up the chimney. I have looked at one at Home Depot, which looks to be decent quality, but ... it says "the doors must be open, while burning the fireplace". Since the unit has a slide damper at the bottom and tempered glass, it doesn't make sense, to me, that the doors must remain open. If that is the case, there would be no reason for the slide damper .... ?? All of the pictures, I see of glass doors, show them burning with the doors closed.
Anybody have any thoughts on this?