Summary To improve the energy efficiency in buildings, a computational optimization method is suggested in this article. The method is designed based on the structure of the adaptive façade. This type of façade system can adjust its visible and thermal transmissivity for actively changing weather conditions. The main concept of this system is the optimization process. This process integrates the DesignBuilder as the building energy simulation tool with an optimization method, called arithmetical optimization algorithm, through the MLE+ toolkit. It is notable that the proposed approach can be applied to different building types and is also not involved in any specific optimization tool. In this regard, two case studies, a typical single office room, and a medium office building are selected to show the capability of the presented approach to improve the energy effectiveness of the building. Based on the results, the energy consumption is decreased by 15.0%–29.1% for the first case study and 14.3%–22.4% for the second case compared to the static façades. The adaptive façades' potentiality is indicated by the important achievements in this study.