[Exeric]

I guess I should add that one really can't retrofit MORE leakage into the house after the house is completed. If you did everything right in sealing it and you got your house passivehaus tight you can't go back in and create a balancing vent hole without creating a drafty point in the house. Rather than create a balancing vent it might just be best to go with an HRV at that point.

The whole idea of having a house that's not extremely airtight, but is consistently airtight, is that there is no big area that leaks more than all the others. There won't be a drafty point in the house then and it will be a happy accident type of thing where a ventilation fan works just fine. It's probably difficult to purposely engineer that "happy accident" into a house but it happens often enough by accident that you would be considered unlucky if it didn't happen in the process of building your house. But if you were that unlucky then you are basically screwed and would have to go with an HRV unless you can cope with at least one big drafty area.