The article deals with the problem of the choice and introduction of energy-saving ventilation installations for the buildings of the housing stock of the early years of construction. Ventilation systems in the housing stock are worn out, do not meet the requirements of the law and in fact are a source of at least a quarter of the energy losses from total energy consumption in the operation of buildings of residential and non-residential funds. Normative documentation regulating the norms of air consumption in living quarters, classification of ventilation systems in the countries of the European Union are given. The paper presents data of a comparative assessment of the use of combined extract and input ventilation with a different composition of equipment. On the basis of these calculations, the most economical ventilation units are distinguished, compared to the operating costs and the cost of thermal energy for the year.