This paper is devoted to the solution of an actual problem — to energy conservation and increase of energy efficiency of buildings. Synthesis of regional experience of design and construction of energy effective buildings is executed. Architectural and planning, constructive and technical aspects of design of buildings are affected. The complex of energy saving actions realized in projects of buildings is developed. The assessment of a thermal performance and energy efficiency of buildings according to requirements of the actual edition Construction Norms and Regulations 23-02–2003 “Thermal performance of the buildings" is executed. On the basis of the carried-out calculations classes of energy saving of buildings are defined. The assessment of energy efficiency of buildings is executed taking into account climatic conditions, the chosen space-planning decisions, orientation of the building, thermal performance properties of the enclosing structures, the accepted system of a heat supply, and also application of energy saving technologies. The received results promote improvement of design buildings quality.