The performance of pupils is unquestionably closely related to comfort. This is strongly dependent on the room environment, which in turn can be controlled to create the optimal conditions. In a natural way, interior wall greening systems can contribute to positively influence the microclimate in the classroom and thereby increase individual performance during the lesson. In this master thesis the influences of two such greening systems in two different schools are analyzed, whereby the role of the ventilation type and their impact also stands in the foreground. The two schools participate in the project "GRÜNEzukunftSCHULE" and are ventilated naturally, meaning manually, and mechanically. Essential aspects to be considered in the measurements are: air temperature, humidity, carbon dioxide concentration and additionally the reverberation time. The first step is to compare the systems in the respective schools and then to compare the classrooms of the two schools with the same interior wall greening system. Researched reference values are used for the evaluation of the processed measurement data. Two findings will emerge. The interior wall greening systems achieve an improved room environment, the greened classes clearly stand out from the reference rooms, and mechanical ventilation makes a positive as well as a negative contribution. Depending on the point of view, this has a supportive or even counterproductive effect.