Standard rolling element bearing life calculations, as outlined in ISO 281, are not accurate for bearings used in refrigerant systems, because the lubrication quality parameter, κ, does not account for the behavior of refrigerant-oil mixtures. The presence of refrigerant reduces the viscosity and piezo-viscosity while increasing the compressibility of the mixtures. This paper presents a novel method for determining the reliability of rolling bearings using rheological measurements and elastohydrodynamic lubrication (EHL) simulations to produce a numerical value of the viscosity parameter κ, as opposed to the standard analytical one, based on a numerical estimation of the film parameter Λ. The proposed approach was validated with compressor tests using polyolester oil and R-1234ze(E) refrigerant under actual operating conditions from a real air-conditioning application. Scanning electron microscope examinations of the rolling bearings post-tests showed that the numerical κ from the new method predicted bearing condition more accurately than the standard κ. Although the example listed here uses a specific refrigerant-oil mixture, the method can be applied to other combinations of refrigerants and oils.