Thermodynamic properties of two fluorinated ethers, that meet the criteria of the potential new-generation refrigerants with considerably low global warming potential (GWP) and the zero ozone depletion potential (ODP), are studied in the present paper. The recommended candidates are pentafluoroethyl methyl ether, CF3CF2OCH3 (245cbE beta gamma), and heptafluoropropyl methyl ether, CF3CF2CF2OCH3 (347sE gamma delta), proposed as alternative refrigerants to replace 1,2-dichloro-1,1,2,2-tetrafluoroethane, CClF2CClF2 (R-114) and trichlorofluoromethane, CCl3F (R-11), respectively. The present paper summarizes the current thermodynamic property studies of the above fluorinated ethers, and their thermodynamic property modeling will be presented. The formulations are developed exclusively on the basis of the PVT property data, both in the single phase and at the saturation states. Using estimated ideal gas heat capacity data, derived properties including heat capacities and speeds of sound are calculated in a wide range of temperature and pressure, and their behaviors show the typical and physically sound characteristics of pure fluid.