In addition to classic lighting and sun protection control, applica- tions for heating, ventilation and air conditioning (HVAC) in particular form an essential part of modern room and building automation. As a worldwide standard for home and building system technology, KNX also integrates further applications. Considering that home and build- ing automation accounts for 40 % of the total energy consumption, energy e ciency is paramount as well as an increase in comfort. The energy e ciency of buildings as well as the in uence of building automa- tion is described in the European standard EN 15232. The methods described there evaluate the in- uence of the building automation and the technical building manage- ment on the energy consumption.