Constantly increasing energy and heat prices lead us to search for more effective use of technologies that reduce their consumption and hence operating costs during the life cycle of buildings and also reduce the negative effects on environment. In the past, we asked for a particular emphasis on the amount of purchase / investment costs by project assessment. Gradually, we recognize that it is important to monitor the future operating costs and realize that the thermal attributes of building materials, which affect the cost of acquisition of the object, also affect the amount of the operating costs of buildings in the phase of use. One way to reduce operating costs is the thermal insulation of buildings. How is it but with the effectiveness of funds spent? Heating do automatically reduce costs after insulation? What time will it take to get the investment returned and what are the factors that matter? These questions should be asked by the organizations providing / making the rental apartments
