But you do have re circulation and makeup air with and an automated system, that, we don't have an actual mechanical control over. The system has to take into account outside air temps, and interior temps to maintain a setting, and it may just do that with flow rates, or it may do that by mixing in the refesh air or recirculating as it sees fit. No, I really don't have a clue as to how the system works because I don't have any schematics, but in turn, not knowing the details, (which I may add no one here seems to know) I cannot dismiss anyone's anecdotal experience or judge it to be true or not.