Abstract: The present disclosure relates to a ventilation system for a building including a conditioning unit, a ventilation unit and a control unit. The conditioning unit is mounted in at least one of a door and a wall of the building for conditioning air as it moves through or into the building. The conditioning unit includes at least one air inlet and an air outlet, spaced from the air inlet. The at least one air inlet communicates with at least one of air within the building and atmosphere and the air outlet communicates with air within the building. The ventilation unit is spaced from and communicates with the conditioning unit for expelling air from the building to atmosphere. The ventilation unit includes an air inlet and an exhaust air outlet, spaced from the air inlet. The air inlet communicates with air within the building and the exhaust air outlet communicates with atmosphere.