It is estimated that 40% of globally generated energy is consumed in buildings [2]. The European Community is setting the target to reduce CO2 exhaust by 20% until the year 2020 [1]. New regulations on the energy efficiency of buildings will help to achieve this target. Beside structural measures, building automation is the key to energy-efficient buildings. The seamless integration and communication of different technologies is the challenge. The complexity of building automation is very often underestimated.