The building sector consumes, even today, about one third of primary energy used in countries like Germany, which, in addition to tons of CO 2 and depletion of energy sources, involves a cost of millions of Euros. This paper shows how, only through the optimization of the system technique regulations, energy savings by a margin of 30% can be achieved in offices and administrative buildings. This potential reduction or even elimination of expenses is possible with the use of the automation system that is proposed in this article.It is important to emphasize that simulation models of HVAC systems and rooms are very often used during the planning phase of a project for a proper system design. However, these simulation tools offer additional possibilities for control algorithm development and performance observation which are not used in practice so far.This article demonstrates that simulation based predictive control, using a system operation that is not depending on a main computer but on the components of an intelligent bus, offers the opportunity of a better utilization of the buildings and their thermal mass.