For the near future the expectation of experts is that the most promising systems will be based on demand-controlled hybrid ventilation technologies. The impact of further development and the improvement of fully mechanical or fully natural ventilation systems on energy savings and indoor air quality is reaching its limits. The hybrid part of the system is of course the minimisation of the electric power of the fan by improving the fan efficiency and low pressure ducting.
Hybrid ventilation systems can be described as systems providing a comfortable internal environment using different features of both natural ventilation and mechanical systems at different times of the day or season of the year. It is a ventilation system where mechanical and natural forces are combined in a two-mode system. The main difference between conventional ventilation systems and hybrid systems is the fact that the latter are intelligent systems with control systems that automatically can switch between natural and mechanical mode in order to minimise energy consumption and maintain a satisfactory indoor environment.