Indoor climate systems in passive houses

According to the definition, passive houses in Europe meet a target energy demand for heating of less than 15 kWh per square meter and per year. This low level for the heating demand is based on heating by a small post-heater in the hygienic ventilation system at 52 0C maximum, while the ventilation system can be dimensioned purely for ventilation purposes. In theory thus the installed heating power is less than approximately 10 Watts/m2. But what happens in practice? The practical realization can be different from the definition and user experiences with indoor climate systems for passive houses may require further adaptations. Belgian example projects and the indoor climate systems in winter and in summer were studied. The study includes inspection of technical details and interviews with occupants of some passive houses in Belgium. The results illustrate the concerns of occupants considering winter and summer comfort in especially bedrooms, low air humidity creating respiratory problems and complex control of installations including temperature control. The research shows that occupants tend to prefer new adapted types of post-heating. Also, a good realization of (passive) cooling techniques is a very important issue in passive houses. The paper gives recommendations on how to improve the user friendliness of indoor climate systems for passive houses