The school was planned with a very sophisticated energy concept. Now, the questions are: how well does the concept stand up in practice, and how can operation of the technical systems be optimised? In order to answer these questions, a large volume of data, e.g. electricity consumption of individual components (heat pumps, ventilation systems, auxiliary electricity for pumps, controllers, lighting), room temperatures, and consumption of heating and cooling energy, was measured for the entire building, recorded in the technical centre, and reported. The results from 2005 confirm the predicted high thermal comfort with good air quality, both in winter and in summer. The air-tightness measurement (n50 = 0.34-1) showed that while the entire building met the requirements, the technical centre indicated significant leaks. Here, subsequent improvements were necessary, most of which are now complete. The wood pellet boiler was practically unnecessary in 2005, as the output of the heat pumps was sufficient. To date, the energy consumption values still show deviations from the planned values. For instance, the heating consumption of 37 kWh/m² p.a. in 2005 is somewhat higher than the calculated value of 30 kWh/m² p.a. The low maximum heat pump supply temperature of 28°C which was planned, was greatly exceeded in 2005 (up to 48 °C) for control-related reasons. This deviation and a number of other problems (e.g. pumps' running times and cycle times) were successfully corrected by optimisation of operations (fig. 6).

The electricity consumption of individual components shows that the optimisation of systems operation had a measurably positive effect. In the summers of 2005 and 2006, due to the high performance of TABS, the building was cooled more than was required. Thus, optimisation measures are being implemented now, and in the future, for adjustment purposes, i.e. for reduction of cooling, in order to lower the pumps' energy consumption in summer (fig. 7). Overall, the support initiative's energy objective, a primary energy characteristic value for heating, ventilation, cooling and lighting of 100 kWh/m² p.a., was not yet fully achieved in 2005, with 116 kWh/m² p.a. (fig. 5). However, it can be expected that this target will be reached in the future, due to the measures which have already been taken, especially regarding the control technology.