This research aimed to implement a finite element heat transfer model to simulate the thermal cycle of steel ladles using an open‐source tool. FEniCS was selected, as it can solve partial derivative equations such as the heat transfer ones, which describes the thermal state of the steel ladle via finite element method. For this, each step of the steel ladle cycle (preheating, waiting steps, and holding) had its own model, comprising specific combinations of boundary conditions. An energy consumption analysis was carried out based on the calculation of the heat flux for each stage of the ladle cycle according to three selected configurations of the refractory lining chosen for the simulation. The results showed that the solutions obtained by both the open‐source method and by the commercial tool (Abaqus) were equivalent. The comparison of different lining configurations, especially using insulators, presented several advantages from the energy point of view. The attained conclusions can be of great interest to the refractory engineers who seek novel solutions to improve the insulating performance of the steel ladle. The present framework makes it possible to test a multitude of different designs and processing operation conditions, making the proposed tool a cost‐effective solution to aid the required improvements to reduce the carbon footprint of critical industrial processes such as steelmaking.