The construction industry is an important segment of the national economy of the Republic of Belarus. In recent years, strict environmental safety requirements have been imposed on the quality of housing being built. The carbon dioxide content in the classrooms’ air of the university as model objects was investigated by the authors. It has been shown that the content of this pollutant can exceed 2,000 ppm. The use of mechanical ventilation systems, especially with heat recovery, allows to solve the problem of poor air quality in residential premises. However, for the successful functioning of ventilation systems, systematic training of the inhabitants and the implementation of educational programs are required.