A Deaerator generally consists of two sections: the Deaerating Heater in the upper part and the storage section in the lower part. The configuration of the Deaerating Heater classifies units into three types: Vertical Heater Single, Vertical Heater Double, and Horizontal Heater Double.

Deaerators are also classified by their deaeration method into Tray type and Scrubber type. In the Tray type, Tray assemblies are stacked in a defined arrangement inside the Deaerator to increase the contact area and contact time between the water and the heating steam to induce deaeration. In the Scrubber type, a structured arrangement of scrubbers is installed inside the Deaerator to bring the water and heating steam into contact and also induce deaeration.