Today the air-cooled reversible chillers are among the most widespread technologies on the European air-conditioning market. The investment costs of such units have become comparable to the nonreversible ones. Exergy-based methodology can identify location, magnitude and causes of thermodynamic inefficiencies within the energy conversion system. So called avoidable parts of exergy destruction being obtained on the base of the exergy analysis determine potential improvement of processes which can be reached in future due to availability, cost of materials and manufacturing methods. The work presents the results of exergetic analysis of reversible chillers providing both cooling and space heating in varying operational modes. Two types of applications are studied for temperatures at rating conditions defined by EUROVENT. In the first case cooling is designed for 12/7 °C system and heating – for the 40/45 °C system. The second type of system has 23/18 °C design temperatures for cooling and 30/35 °C for heating. Compared to the first one the second type of the reversible chiller has a 26% and a 20% decrease, respectively, of the total and avoidable exergy destruction. The outcomes obtained showed that the both inside and outside heat exchangers have the highest priority for improvement revealing the biggest shares of avoidable exergy destruction within the system. Compared to the heat exchangers the compressor enhancement was found to lead to the lowest potential decrease of exergy destruction