When designing the enclosing structures (ES) of buildings, calculating their required heat transfer resistance and choosing the order of arrangement of structural layers, it is important to take into account the quasi-stationary and non-stationary nature of transfer processes in ES, which brings the mathematical model closer to the real structure. The ES calculation methods discussed in the article make it possible to trace the changing pattern of heat propagation in the ES throughout the day for the cold (CP) and warm (WP) periods of the year, under different boundary conditions (BC) on the inner and outer surfaces of the fence. Numerical modeling of similar transfer processes for various multilayer ES was carried out using Mathcad and Excel, then the reliability of the results obtained was assessed by comparing them with the results of numerical calculations in Elcut and Ansys Fluent.