The exhaust fan should be positioned in such a way that the fresh air drawn in will move throughout the room or building to prevent the formation of air pockets. The best results are usually obtained when the fan is fitted on a wall opposite the inlets. The Fan should not be installed too close to open doors or windows as this will cause the air movement to be short circuited between the fan and the adjacent inlets and the other parts of the room will remain unventilated. Also, the Fan should be fitted at the highest possible level so that smoke, steam or odour laden air, normally warmer than the ambient temperature within the room and which tend to rise, can be effectively exhausted. The Exhaust Fan should also be installed at greater height than ceiling Fan blades, if both are located in the same area.