There is a difference. You've got two things mixed up.
ACH50 is the air changes a building goes through at pressure. Requires a blower door to measure.
ACH without the blower door will be lower, quite a bit lower.
Passivehouse, green, blue, red, purple, star, diamond, etc standards and comparisons are made at the ACH50 level. You need 0.6ACH50 to get to be a passivehaus.
This doesn't mean it's exchanging 60% of its air with all the doors and windows shut without the blower door in place.
Think about this. If I open my window and put my furnace 800CFM (48000CFH) blower into it and open all the rest of my windows, I'll only be at 2.73ACH. That's a furnace blower maxxed out, plenty of wind there!
There is a difference between a static air exchange through infiltration and forced infiltration with a blower door. The level of air exchange will not be the same.
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