The project is a side project to the main project to reduce the energy performance of the Karl Jeřábek elementary school building 941, Roudnice nad Labem, Litoměřice district located on the plot of parc. no. 1595 in k.ú. Roudnice n. L., in the urban conservation zone The object of the project is the installation of a forced ventilation system with heat recovery consisting of 2 VZT units. This is a comprehensive project to reduce the energy performance of the building combined on 2 applications.