The energy is an important parameter for all countries and the usage of it needs to be planned carefully. In the world, energy consumption HVAC equipment in residential buildings ranges between 16% and 50% of total energy consumption, depending on the countries. This energy is mostly used by central heating systems (CHS) for heating. Design of CHS in buildings is very important in terms of rational energy usage. CHS’s are generally designed using energy analysis (First Law). However this analysis is not adequate itself, so second law analysis is also required for evaluation of system performance. In this study, energy and exergy analyses of a heating system are performed using the data and experiments of 3 years in a multipurpose building (a shopping center) which needs heating in an area of 80.000 m2 in Ankara, Turkey. As a result of the energy analysis, it is shown that the lowest efficiency is in the heating exchanger, and the highest efficiency is in the boiler. On the other hand, there is an opposite situation for exergy analysis. These results indicate that exergy analysis is more realistic than energy analysis, and system performance can be increased by improving the boiler.