Abstract: A low temperature food merchandiser having a cabinet with an open front product area, a primary cold air system for maintaining substantially constant frozen food temperatures of 0.degree. F. or ice cream product temperatures of -5.degree. F. in the product area including the formation of a series of vertical curtains of primary low temperature air extending across the open front of discrete product area sections, a secondary air system protecting the primary air curtains, and the primary system also including primary evaporator means constructed and arranged to operate at elevated coil temperatures in the range of -5.degree. F. to -8.degree. F. to maintain 0.degree. F. product temperature or coil temperatures of -12.degree. F. to -15.degree. F. to maintain -5.degree. F. product temperatures, and including high efficiency reverse air cycle defrost means for periodically defrosting the primary cooling means.