In this paper, the test results of a performance analysis of new alternatives; R-410A, R-507, R-407C, R-408A and R-404A proposed as substitutes to HCFC-22 are presented. The test results were obtained using an air-source heat pump with enhanced surface tubing. Performance tests were conducted according to the ARI/ASHRAE Standards. The performance data demonstrated that as an interim replacement, the R-404A blend has a superior performance particularly at low temperatures among the proposed blends. Furthermore, the alternatives to R-22 are characterised by high discharge pressure compared to that of R-22. In particular, R-410A has the highest discharge pressure among the blend studied. R-407C has similar discharge temperature to R-22 at temperatures lower than - 8 degrees C. Copyright (C) 2000 John Wiley & Sons, Ltd.