The project deals with the reduction of the energy intensity of the building of Karel Jeřábek Primary School 941, Roudnice nad Labem, the district of Litoměřice located on the plot of parc. no. 1595 in k.ú. Roudnice n. L. The object of the project is to replace the filling of the openings (windows, doors) of the envelope of the building and the insulation of the soil space in the historical part of the building, which is located in the urban monument zone. This is a comprehensive project to reduce the energy performance of the building, combined on 2 applications, of which the 2nd application (5.1b) is dealt with by RZT with recovery.