If the use of air inlet valves is virtually impossible or if you want to ventilate on the basis of equal pressure, the air can be brought in by applying a partial vacuum or by using an intake fan. The air supply chimney features a unique air distribution unit made up of stainless steel fins. They can be positioned in the direction required in order to easily avoid any obstacles such as purlins. The built-in recirculation section ensures that hot air in the house is mixed with the incoming fresh outside air. The insulated upper section of the chimney and the stationary air layer of 8 mm between the inner and outer walls prevent the air from condensing in the chimney. The backdraught shutter determines the recirculation air-to-outside air ratio.