A humidifier system for humidifying a microenvironment in a neonatal incubator includes a reservoir configured to hold water to be evaporated for humidifying the microenvironment. A chamber divider defines a heating chamber within the reservoir, and a movable heating element is positioned at a surface level of the water inside the heating chamber so as to heat the water at the surface level inside the heating chamber. The heating element is configured such that it is moved downward within the heating chamber so as to maintain the heating element at the surface level of the water as an amount of water in the reservoir decreases.