Main problem: recently, much attention has been paid to energy saving in production, especially when it comes to industrial units that burn fuel. There are several ways to maximize the use of the heat released during the combustion process, for example, to reduce the temperature of the flue gases at the outlet of the unit, by maximizing its use, both in the technological process itself and by installing additional heat-receiving units, for example, air heaters or other heaters. Another way to save money is to reduce heat losses through the lining of these high-temperature units. Metallurgical units that consume a large amount of energy and fuel require an analysis of their consumption, and ways to save their consumption based on the results of the analysis. Purpose: this article considers the possibility of replacing the existing inner insulation layer of the second and third sections of a high-temperature unit - a metallurgical furnace, with a new one with better technical and economic indicators. Methods: the possibility of replacing the existing inner insulation layer of the second and third sections of the high-temperature unit with a new one, with the best technical and economic indicators, was considered. The calculation of heat losses by thermal conductivity through the side surfaces and the roof with new insulation was performed, and the economic efficiency of the proposed solution was proved. Results and their significance: replacing the existing inner layer of insulation - refractory concrete PHLOCAST M30 (thermal conductivity coefficient from 1,4 to 1,45) with the proposed CERALIT GUN HK 70070 (thermal conductivity coefficient from 1,03 to 1,12) will reduce heat loss to the environment, and thus to reduce fuel consumption for the furnace.