Building occupants have a considerable interest in the current state of their environment. Studies have shown that making building data transparent helps occupants to understand their energy consumption. In addition, transparent data can help to increase the Indoor Environmental Quality (IEQ) and therefore increase the occupants’ health. However, such data is often not accessible, intransparent and mostly not easy to understand for a typical user. Modern buildings equipped with various sensors tend to collect massive amounts of data, but often fail to provide information in an accessible, user-friendly and meaningful way. To give an example, a level of particulates at 170.000 ppcm might not be a helpful answer to understand the air quality. I pose the research hypothesis that an effective visualization of IEQ-related data in a smart building helps its occupants to develop an awareness about their IEQ. Furthermore, many smart environments offer diverse proprietary and therefore incompatible controlling systems. In order to interact with these or to gather information, its occupants have to switch between multiple interfaces. As a solution, I combine comprehensive and meaningful IEQ information with the possibility to control and improve the environment using a mobile application. The system’s usability is evaluated in iterative cycles with application domain experts and by means of two user studies. The first study serves the purpose of illustrating the user’s comprehension of the design concept whereas the second study evaluates the resulting system’s performance in terms of usability. The studies show that the mobile application enables users to get a better understanding for IEQ-relevant data.