One of priority directions in modern building is maintenance of energy efficiency of buildings and constructions. This problem can be realized by perfection of architectural, constructive and technical decisions. The particular interest is represented by an influence estimation of temperature and moisture mode of enclosing structures on a thermal performance and energy efficiency of buildings. The analysis of the data available in the literature has shown absence of effective calculation methods of temperature and moisture mode in edge zones of enclosing structures that complicates the decision of this problem.The purpose of the given work is an estimation of edge zones influence on a thermal performance and energy efficiency of buildings. The design procedure of energy parameters of a building for the heating period, realized in the computer program is developed. The given technique allows settling an invoice power inputs on heating, hot water supply, an electrical supply. Power inputs on heating include conduction heat-losses through an envelope of a building taking into account edge zones, ventilation heat-losses and leakage air (infiltration), internal household thermal emissions, heat-receipt from solar radiation. On an example it is shown that the account of edge zones raises conduction heat-losses through an envelope of a building on 37 %, the expense of thermal energy on building heating on 32 %, and the expense thermal and electric energy on 13 %. Consequently, thermal and moisture mode in edge zones of enclosing structures makes essential impact on building power consumption. Perfection of the constructive decision leads to decrease of transmission heat-losses through an envelope of a building on 29 %, the expense of thermal energy on building heating on 25 %, the expense of thermal and electric energy on 10 %. Thus, perfection of edge zones of enclosing structures has high potential of energy efficiency.