The article raises the problem of improving the energy efficiency of buildings in operation with a constant increase in energy prices, which is now becoming increasingly important. The analysis of the design deci-sions of the buildings of educational institutions of Donetsk region was carried out; the main typical series of the region were highlighted and given. The issues and the factors affecting the heat and moisture characteristics of enclosing structures of educational institutions were discussed. The values of resistance to heat transfer for the most common standard series of secondary schools are given. The modeling of temperature fields of nodes of public buildings of standard series was made. The most unfavorable design solutions of serial buildings were identified by the following factors: the temperature of the inner surface of the outer enclosures and the temperature difference between the average temperature at the surface and the air temperature in the room. Possible ways of thermo-modernization of such buildings with consideration of the requirements for temperature and breathability are considered. The influence of heat-conducting inclusions on the heat-moisture regime of external enclosing structures during partial and full thermal modernization is estimated. The analysis of various methods and ways of warming the buildings of educational institutions are performed. The advantages and disadvantages of the proposed options from an economic point of view are indicated, as well as on the basis of the requirements of fire regulations.