This project deals with ways of cleaning windows via device which is mounted on a glass surface of medium height buildings (up to 50 m). There are detailed analysis of products that are currently active on market. Analysis is followed by some of the most important criteria for window cleaning robot. Function structure, ideas for function realisation and, later on, the concepts itselves are made, based on criteria, demands and functions of product. Detailed concept is to be chosen and is corroborated with 3D models, documentation and roughly calculations.