The present invention provides single units that contain a large lower chamber, and one or more display shelves above this chamber on the inside of the unit. A roller grill or other large appliance may be provided in the lower chamber, or the chamber may be left open to display large food products or other items. The shelves may be heated for keeping foods displayed on the shelves warm; however, the shelves need not be heated for food products that do not need to be kept warm. Heating elements, lights and sensors may be adjusted using electronic controls to provide optimum temperatures inside the various chambers of the display units. Display units of the present invention allow store owners to utilize the space above a roller grill or other appliance to merchandise additional food products as opposed to requiring a separate food merchandiser to occupy additional valuable counter space. The performance of the roller grills of the present invention is improved over stand-alone roller grills, thereby reducing the potential for lost sales due to food not being sufficiently heated.