Interaction with user interfaces only with usage of hands and bodies was a few years back still science fiction, but now present reality. Touchless interfaces are slowly becoming main-stream and therefore it is of crucial importance to address them in a concise and standardized way. Usability is an important factor in all software quality models and a key factor during development of interactive applications. The objective of this paper is to address usability challenges the authors are facing during touchless application design. A conceptual usability case study is proposed with new human-computer interaction factors in mind. Factors like efficiency, ease-of-use, pleasure, fatigue, naturalness, smoothness, responsiveness and accuracy are identified and related to usability scenarios.