In this thesis, a batch furnace with internal dimensions of 2750 × 2750 × 3050 mm, which is heated by 6 burners with a total heat flow of 1758 kW, was analyzed. The fuel used in this furnace is methane with a mass flow rate of 0.03516 kg/s. The actual mass air flow is 0.385 kg/s. The insulation of the furnace on the sides and on the top is made of ceramic fibers, and the bottom is made of refractory bricks. The construction of the furnace with doors, insulation, burners, pipelines, heat exchanger and other main parts is drawn in the Autodesk Inventor Professional program. The temperatures and thermodynamic characteristics of the furnace, which are achieved in the furnace, were analyzed by analytical calculations made in the Engineering Equation Solver (EES) program, and numerical analysis in the Ansys Fluent CFD program. The results of the analytical calculation and numerical analysis indicate that this furnace can achieve an adiabatic temperature between 1953 and 2177 K, and the actual temperature around 1340 K. Numerical analysis showed that a uniform temperature and good mixing inside the furnace are achieved, which favors the heat treatment of a larger number pieces. The results indicate that this furnace can be used for various heat treatments of different types of materials, where the atmosphere in which the pieces are processed is not of crucial importance, because the products are in direct contact with flue gases. Deviations of analytical calculation and numerical analysis results are on average around 20%, which is acceptable.