This article presents a physical and mathematical model for the utilization of a part of the heat flow passing through the exterior fence of a building. The option of using this flow to heat the supply air in the outer wall of the building, which has a ventilated layer in its design, is being considered. The article analyzes the thermal characteristics of walls with a ventilated interlayer, calculates the amount of recycled heat flow and evaluates the energy-saving effect of this approach. Possible problems and limitations of using this technology are also considered. The results obtained can be useful in the design and construction of energy-efficient buildings.