Occupants of buildings usually have the opportunity to control the indoor environment with the help of different elements and devices. These include, for example, windows, luminaires, radiators, and shading systems. Depending on the availability and effectiveness of these devices, the quality of the indoor environment is affected. Due to the fact that there is a lack of certification procedures for this aspect of the indoor environment of buildings (i.e., controllability) this master thesis deals with the specification potential of the Ecological Valency in built spaces. Toward this end, first a potential theoretical foundation for this purpose is identified (in terms of the Vienna School of Human Ecology) and previous related efforts are briefly reviewed. Subsequently, a specific attempt for an Ecological Valency evaluation method is presented. As part of this approach, five main categories of control equipment are suggested to be documented in various rooms of a building. They include windows, shading, lights, heating and cooling systems. Whereas, the first component of this method deals with the availability of these control devices and elements, the second part looks at their spatial distribution, effectiveness (both objective and subjective), interface quality, and ecological quality. The presented evaluation method is tested for six different rooms of an office area in an educational building in Vienna, Austria. About thirty participants conducted the evaluation of this area based on the proposed method individually. This is done to test the usability of the method itself but also to document the degree to which the different evaluation results could diverge when the same room is evaluated by different participants. While some of the participants work in this office area, others were not familiar with it before conducting the evaluation. Hence, aside from the overall consistency of the results, the difference between the results from the occupants and the visitors is analyzed as well. The Outcome of this experiment but also the feedback from the participants are included in this master thesis.