The invention relates to a ventilation system (2) for a building having an air suction opening (4), an air guide duct (6) adjacent to said opening, in which duct a heat exchanger (16) containing a phase exchange material is located, a ventilator (10), and an air outlet opening (8) arranged at the end of the air guide duct (6), characterized in that the ventilation system (2) has a system for supplying a liquid, having at least one port opening (20) from which the liquid that exits from the port opening (20) reaches the surface of the heat exchanger (16).
