Multi-criteria decision support for the procurement of retrofit ventilation systems in educational buildings

Better indoor air quality is becoming more and more important. Especially in educational buildings such as schools and universities, where many people are in a confined space, it is beneficial if ventilation concepts can be compared with each other. In this paper, cost-effective extract ventilation systems are compared with conventional natural window ventilation, with the aim of creating a multi-criteria decision-making tool, which informs decision-makers when retrofitting a room with an additional hybrid system. Both quantitative parameters such as temperature, relative humidity, CO2 concentration, capital costs, air volume flow and draughts, but also qualitative parameters such as comfort and aesthetics are compared as part of this investigation. With the help of empirical measurements as well as survey data, which are intended to record the subjectivity of the occupants, the data necessary for the preparation of the decision tool were collected. After the development of the multi-criteria decision-making tool, the tool was tested, with the aim of a balanced decision for or against the purchase of the extract system by the test person. In the future, this assistance can be used by schools and universities with the aim of improving the indoor air quality of classrooms or seminar rooms through the constant supply of fresh air, thus improving thermal, acoustic and visual comfort.