A heater assembly for a heating, ventilation, and/or air conditioning (HVAC) system has a heater and a controller enclosure. The heater has a plurality of heating elements in a frame that has two opposing ends. The controller enclosure has two end walls and a plurality of side walls in a non-rectangular polygonal configuration. One of the two opposing ends of the frame is coupled to one of the two end walls such that an orientation of the heating elements may be changed based on respective locations of the plurality of side walls of the controller enclosure.