The poetic name “air fountain” gives you a clue as to what this 15m-deep shaft is for. It was built in 1890 and serves to ventilate the halls.
For a large structure such as the main building of the University of Vienna, heating and air circulation are essential. Today, fresh air is still pulled into huge shafts like this one in the arcaded courtyard and sent by a motor-run ventilation system through a labyrinth of underground passages to filters. The air is then warmed and humidified if necessary and sent to the Main Ceremonial Chamber, Audimax and large reading room. The air system has since been renovated – it now operates using pressure, meaning it is able to carry cold and warm air to where it is needed. The amount of air used per hour could be reduced from 46,000m3 to 20,000m3 in this way.
The circulating air used to be heated with various methods throughout the University. There was a steam air heater for the large reading room, Main Ceremonial Chamber and Audimax, a direct steam heater for some lecture halls and individual stoves for the dean’s offices.
Nevertheless, or perhaps because of this, teachers and students often complained about the heating in the first decades of the University’s existence. Again and again rooms would stay cold. These problems have been a thing of the past since the heating was centralised in the 1960s and the changeover to district heating in 1986.