Mechanical and natural ventilation systems have developed separately during many years. The natural next step in this development is development of ventilation concepts that utilizes and combines the best features from each system into a new type of ventilation system - Hybrid Ventilation. Buildings with hybrid ventilation often include other sustainable technologies and an energy optimisation requires an integrated approach in the design of the building and its mechanical systems. Therefore, the hybrid ventilation design procedure differs from the design procedure for conventional HVAC.
Natural ventilation is a sustainable, energy-efficient and clean technology that is well accepted by occupants. It can be used to provide fresh air for occupants as necessary, to maintain acceptable air quality levels and to cool buildings in cases where climatic conditions allow. The successful application of natural ventilation techniques and the effectiveness of natural ventilation are determined by the prevailing outdoor conditions and microclimate as well as by building design and building use.