The structural features of the thermal unit for the production of molded heat insulation materials and their technological parameters must be in full compliance with the properties of the initial materials and are determined by the production program of the enterprise. Based on the peculiarities of gas dynamics formation, the structural parameters of the thermal chamber are determined: dimensions, shape of the internal surface, presence of longitudinal and transverse seals, extent and parameters of heat treatment. Method of thermal calculation including separate consideration of conditions of mineral wool carpet heating in heat chamber and formation of heat carrier flow in furnace is proposed.