A ventilation system performs an essential role in the elimina- tion of pollutants originating in the air-space [3]. In addition, the performance of the mechanical ventilation system has an impact on thermal comfort; for example cold draughts can produce an unpleasant living or working environment for the occupants. Studies have shown that ventilation systems in buildings are largely responsible for Sick Building Syndrome. These ventilation systems are either wrongly designed or are poorly maintained. Ventilation is an important parameter in the air quality. All the injurious contaminants need to be exhausted effectively using the ventilation system [76].