Advanced energy-efficient ventilation.

It is often stated that advanced ventilation or air conditioning is expensive or energy-wasting. There are, however, several examples of highly energy-efficient air conditioning systems in industrial, commercial and public buildings. Energy-efficiency can be achieved by - optimizing air flows or demand-controlled ventilation - avoiding simultaneous heating and cooling (except if "free") - advanced automatic control system - good operation and maintenance The performance of ventilation and air-conditioning depends on several factors in the building process. The most important one is the "end user": inhabitant or other occupant. We should build ventilation for ordinary people who also should know what to require. Of course there are several persons or bodies who are responsible of the result: the owner of the building, the builder, the designer, one or several contractors and the maintenance personnel. If the end users become more aware of the elements of good indoor air and learn to require it, then it is obvious that the quality of ventilation systems will be improved.