Heating, Ventilating, and Air Conditioning (HVAC) systems play a major role in energy consumption of modern buildings. Nowadays, the main challenge for the design of HVAC systems is the development of efficient methods of control to reduce energy consumption and provide comfortable climate conditions in buildings. One of the key factors influenced on climate conditions is the number of people in the room. The main goal of our study was to implement the modified Rule-based control that used occupancy information. The comparison between traditional Rule-based control and standard control of the HVAC system in the building shows the potential to increase the efficiency of HVAC systems.