This paper presents the heat-transfer assessment of different low GWP substitutes for traditional HydroFluoroCarbon (HFC) refrigerants obtained by applying both an experimental analysis based on the direct measurement of thermal (heat transfer coefficients) and hydraulic (pressure drops) performances and a theoretical analysis based on a specific Performance Evaluation Criteria (PEC), the Total Temperature Penalisation (TTP), in the specific case of boiling and condensation in a commercial Brazed Plate Heat Exchanger (BPHE). The results of both the experimental and the theoretical assessment confirm that the refrigerant R32 has comparable heat transfer characteristics to R410A. Similarly the refrigerants R290 and R1270 exhibit superior heat transfer performance to R404A; the refrigerants R152a, R1234yf and R1234ze(E) show heat transfer characteristics comparable to R134a and R1234ze (Z) exhibits superior heat transfer performance to R236fa. The coupling of experimental and theoretical assessments provides a sound procedure for the heat-transfer assessment of the low GWP alternatives for traditional HFC refrigerants. (C) 2019 Elsevier Ltd. All rights reserved.