High heat Ventilation is based on the principle that the difference in pressure between the air inlet and exhaust air vents in a building allows natural air exchange to take place. The pressure differences arise due to; a) the buoyancy forces in the building caused by differences in density between the air in the building and the outside air, and the difference in height between the air inlet and exhaust air vents; b) the air currents in the building. Accordingly, the volume of air flowing through the buildings depends on the surplus heat in the building - caused by the convection heat that is emitted into the room air (internal cooling load), the external cooling load (transmission through insolation), wind speed, wind direction, and building geometry.