IoT solutions enable to gather more detailed consumption data, and by adding other types of sensors to the system, it brings us to new functionality for process and business related monitoring and management. As a measurement object a whole building is selected, which is built in the last few years, already has the Building Management system, lighting, HVAC systems, and in consumption it is comparable also to industrial buildings. The building and measurement data for experimental purposes are arranged in three levels, where the zone level is focusing on rooms covered by one ventilation machine. For data analysis, real measurement parameters like electrical power consumption, room temperatures, humidity, CO2levels, heat energy, ventilation system pressures and also data from the meteorological weather station are obtained simultaneously for several months, using LoRaWAN network and sensors, thus giving ability to have wide data analysis options, to crosscheck complex systems. Detailed measurements and further data analysis show that even new building management systems have errors and there are possibilities to improve the energy efficiency, especially during the exploitation period, where many human errors could be traced and corrected using smart algorithms.