Master thesis presents dependence between thermal stability of the enclosure structure and its design. Influence of thermal resistance on the enclosure structure average temperature is considered. For the research, three frequently used types of enclosure structure in Russia were taken. The average temperature and cooling time were found for each wall. It was proved that thermophysical characteristics of materials directly affect the thermal processes in the wall. Big thermal resistance does not mean big thermal stability. Thermal stability of the building envelope increases with the increase of thermal conductivity coefficient, specific heat and density. The paper considers the possibility of applying the research for effective selection of materialsin construction and for heat loss reduction.