This paper presents pressure-drop data for inside evaporator and condenser coils of refrigeration and air conditioning systems using hydrofluorocarbon (HFC) refrigerants and blends. Computational fluid dynamics (CFD) was used to simulate the two-phase flows of different refrigerants through two types of coil common to the evaporator and condenser components found in a typical vapour-compression system. A comparison of single-phase and two-phase flows is made with respect to pressure drop across the evaporator, firstly at constant temperature for single-phase saturated vapour, and secondly at increasing temperature with varying components such as density and viscosity for two-phase vapour. Pressure losses of HFC refrigerants and blends were compared with data for conventional refrigerants and data provided by other researchers.