The object of research is a ventilated facade with air buffer zones. The problem of heat flow rejection from double skin facade buffer zones by aeration is urgent to reduce the cooling systems load of buildings and reduce energy costs in the summer period. Methods. The article presents a method for calculating heat flow rejection from double-skin facade buffer zones by aeration. The methods is based on the application of the following mathematical equations and calculation methods: the equation of external air density and air in the buffer zone, the equation of gravitational pressure and mass external air flow through the supply hole. Results. The dependence of the heat flow rejection from double skin facade buffer zones by aeration from different internal air temperatures is established and can be represented by a linear dependence of the form  The calculation of the heat flow rejection from double skin facade buffer zones by aeration of the Tower high-rise building «Lakhta Center» located in the cold continental climate zone (Dfb) is presented. The heat flow removed from the buffer zone during its aeration is 14676 W. Based on the linear approximation of the dependence graph  the following coefficients are obtained: a= – 3873.4; The coefficients can be used to determine the load on the cooling system of the building. The results can be adapted to calculate the heat flow rejection from double skin facade buffer zones by aeration for any façade building with air buffer zones for any climatic conditions.