A pressure support system configured to provide pressure support therapy includes a humidifier that holds an enhanced amount of liquid while enhancing the power consumption of the pressure support system and enabling relatively rapid adjustments to humidity level. The humidifier includes a humidification chamber and a holding chamber, and a partition that divides the holding chamber from the humidification chamber such that liquid from the holding chamber replenishes liquid held in the humidification chamber. The partition, however, also provides a level of thermal isolation for the humidification chamber from the holding chamber.