The walls of a normal modern insulated house are already completely air tight, first layer behind the walls seen from the inside is a plastic sheet to prevent h

The walls of a normal modern insulated house are already completely air tight, first layer behind the walls seen from the inside is a plastic sheet to prevent humidity from indoor human activities to get into the insulation. After building a new house they literally try to inflate it like a balloon and measure the pressure to ensure there is no leakage. Controlling humidity and air freshness is done through vents, usually combined with a heat exchange to not let out all the warm air you just heated up. Condensation accumulating larger drops might be a bigger issue with glass though, but only if it's already humid on the inside.