The effective use of plan area is more crucial in high-rise buildings, since they are mostly narrow compared to the conventional buildings. The measurement of the overall thermal transmittance of lightweight steel-framed walls, including the effect of thermal bridges due to metal structure, is a challenge for designers, engineers and energy audits. In this paper the energy efficiency light-weight wall technology for over story of buildings was considered. In this work was developed a mathematical model of non-stationary heat transfer through the enclosing wall using the lightweight wall technology and evaluated the efficiency of various designs of lightweight wall. In this model, the profile perforation is taken into account due to the results of the solution of the test problem while maintaining the possibility of using structured grids with the number of elements not exceeding 1 million, which allowed to obtain more accurate results.