Air source heat pumps (ASHPs) have been increasingly used to promote energy savings and reduce environmental pollution. However, the evaporator frosting is one of the largest problems in ASHP systems during the heating operation. To examine this issue, a novel frost-free ASHP system has been developed. Nonetheless, the system performance and energy consumption are significantly dependent on the climate conditions. This research aims to identify the characteristics of the novel frost-free ASHP system with radiant floor heating in three different climate zones, China. TRNSYS 17.0 software was employed to investigate the seasonal performance of the new system based on the typical envelope thermal characteristic parameters in the entire heating period in three cities, i.e. Beijing (cold A zone), Xi'an (cold B zone), and Chengdu (hot summer and cold winter zone), located in different climate zones, China. The results showed that the heating seasonal performance factors (HSPFs) of the studied system were 3.9%, 1.9% and 9% higher than the conventional system in Xi'an, Beijing and Chengdu, respectively. It was concluded that the system could operate effectively and reduce substantial energy consumption in comparison with the conventional ASHP system for space heating in cold climate zones.