A refrigerator appliance includes a cabinet that defines an opening with a plurality of racks mounted in the cabinet. A door is mounted to the cabinet at the opening. A divider is configured to separate the cabinet into a first cabinet portion and a second cabinet portion. The divider includes an insulation block with a top cover mounted to the insulation block. The top cover includes a top foil heater. Also included in the divider is a bottom cover mounted to the insulation block. The bottom cover includes a bottom foil heater. A plastic extrusion is mounted to a side of the insulation block, and the top cover and the bottom cover include a forming on at least two sides. The forming of the top and bottom covers engages with the plastic extrusion.