Global pressures on hydrofluorocarbon (HFC) refrigerants have reached new levels. With ongoing country ratifications of the Kigali Amendment to the Montreal Protocol and refrigerant shortages across Europe driven by the F-Gas regulations, equipment manufacturers are working hard to implement lower global warming potential (GWP) solutions. R-404A is one of the higher GWP refrigerants (GWP100 Year = 3,922, per AR4) used widely in commercial refrigeration. Several very low GWP (LGWP) candidates have emerged as potential replacements. For many hermetic and split system applications, hydrofluoroolefin-based (HFO) blends represent lower flammability alternatives to hydrocarbon (HC) refrigerants, that also allow for significantly larger charge sizes. Two mildly flammable, very LGWP blends, XL40 (R-454A) and XL20 (R-454C) were tested and compared to the R-404A baseline performance of a commercially available, double-door, upright reach-in freezer via soft-optimization testing. Refrigerant compatibility with lubricants and other system materials was also examined. Miscibility, water solubility, and dielectric properties were also characterized