Abstract: A steam exchange humidifier including a heat exchanger inside a tank, the tank includes a drain and fluid inlet port for fluid in and out of the tank and a steam outlet. The heat exchanger includes a heat exchanger array, a steam collector, a condensate collector, a steam supply port and a condensate return port. The steam collector is connected to the steam supply port, and the condensate collector is connected to the condensate return port, the steam collector and the condensate collector being connected by the heat exchanger array, the tank being a generally vertical body.