> What "Replacing the air fully" equates to in terms of volume is already a factor of the size of the room/house. Exactly. If one person lives in a castle, do

> What "Replacing the air fully" equates to in terms of volume is already a factor of the size of the room/house. Exactly. If one person lives in a castle, do we need to replace all the air every hour? Certainly not. If we are talking about a person in a 5sqm room (for sleeping) then replacing all air every hour won't be sufficient. There are more factors besides the number of people and the air volume, but I really didn't want to go into so much detail.