A CPAP apparatus is configured to deliver a flow of pressurized, humidified breathable gas to a patient's airways. The CPAP apparatus includes a blower, a humidification unit and a dehumidification unit. The blower is configured to generate a flow of breathable gas pressurized within a predetermined pressure range. The humidification unit is configured to humidify the pressurized breathable gas discharged from the blower. The dehumidification unit is configured to draw condensation from ambient air and operate at the same time as the humidification unit. An air outlet of the CPAP apparatus is sealingly attachable to an air delivery tube and patient interface assembly.