The submitted diploma thesis deals with wind machines in densely populated areas. The aim of the work is to design a appropriate wind machine for use on the roofs of buildings, including all the specifics that the air flow in the city may contain. At the beginning, the work focuses on the production of electricity in cities in general, which results in an ideal system of obtaining energy for households. Furthermore, the work deals with the wind in general, where all its specifics are taken over. A very important part of the work is the study of the specifics of air flow in the urban environment together with the numerical simulation of this flow, which results in certain regularities of the location of wind machines on the roofs of buildings. The work then passes to a search of used wind machines, from which the most suitable candidate for use in cities is subsequently selected. The last part of the work is the design of the machine itself for a specific location. In this chapter, the design wind speed is determined from the measured data, which is later followed by the calculation of the geometry of the blades, and finally its benefits and advantages are determined from the properties of the wind machine