Research on energy efficiency of today's buildings focuses on the monitoring of a building's behavior while in operation. But without a formalized description of the data measured, including their correlations and in particular the expected measurements, the full potential of the collected data can not necessarily be exploited. Who knows if a measured value is good or bad? This problem becomes more virulent as smart control systems sometimes exhibit intelligent, but unexpected behavior (e.g. starting heating at unconventional times). Therefore we defined a methodology starting already at the design of the building leading to a formalized specification of the implementation of a building's management system, which seamlessly integrates to an intelligent monitoring. DIN EN ISO 16484 proposes a method to describe functional requirements in an easy to understand way. We extended its use of state machines to our proposed concept of state based modeling. This proved to be a wholesome approach to easily model buildings and facilities according to the DIN EN ISO 16484 while providing the possibility to apply sophisticated and meaningful analysis methods during monitoring.