The present invention provides a binary refrigerant mixture that can be used in single or dual evaporator refrigeration systems to provide for efficient cooling without the use of a high global warming potential (GWP) hydrofluorocarbon refrigerant such as R-134a and that is less flammable than a hydrocarbon refrigerant such as R-600 (n-butane) or R-600a (isobutane). Further, the binary refrigerant mixture can be classified as an A2 refrigerant in that it has a heat of combustion of less than 19 kilojoules per kilogram. In addition, the binary refrigerant mixture has a comparable energy efficiency when compared to R-134a and can be used in refrigeration systems designed for use with R-600 or R-600a refrigerants without having to change their design (i.e., without having to change the compressor design).