The viscosity, thermal conductivity and Prandtl's number of HFC and HFO refrigerants were studied using an excess entropy scaling approach. Based on it, the complex temperature and pressure dependence of refrigerants under consideration were reduced to simple functions of the residual entropy computed using Polar PC-SAFT. The model coefficients were fitted to experimental data at saturated conditions and used to predict transport properties across a wide range of temperatures, up to 1000 bar. The model was able to capture the minimum in Prandtl's number observed near the critical point. The uncertainties in thermal conductivity predictions are comparable with those obtained with the well-correlated NIST REFPROP extended corresponding states approach (ECS), with maximum average deviations of around 3%. Moreover, predictions of the HFO refrigerants viscosities showed lower deviations than ECS. This work is a step forward in the development of predictive models for the design of optimal low GWP refrigerants.