Assuming that "northern climate" means that cold is more of a problem than heat, then its a bit odd, yes. Long time since I had to do any of this, but the answer used to derive from the heat source. If it involves any form of flued combustion, then there needs to be a fixed air-intake vent of at least the same cross-sectional area as the flue, or you start running out of oxygen if the sealing of the building envelope is too effective. If there's no combustion then it never used to matter, but with excessive sealing it would depend on the system. Reverse cycle A/C includes an amount of air replacement, but a lot less than 15 c.f. / minute. And it can't measure the number of persons can it? So probably the question is "how long is a piece of string?". There are infinite variations for "person". Adults? children? Don't forget the family dog(s) :-)
It may not be politically correct, but you cannot entirely eliminate user interaction: "Can you open the window a touch? it's a bit stuffy in here ... "