The increase in the global population, along with the industrialization of human life, has led to a daily rise in energy consumption. This trend has, in turn, contributed to issues such as greenhouse gas emissions. A significant portion of energy consumption is attributable to the building sector. Nowadays, various technologies, such as atriums, are employed to reduce energy consumption in buildings. In this study, four atrium designs were proposed and evaluated for a school building in Tehran. The Design Builder software was used to assess the respective systems. The results indicate that Sketches 3 and 4 are not energy-efficient and lead to an increase in the building’s overall thermal load. In Sketch 2, the heating load decreased by 23.15%, while the cooling load increased by 9.59%, resulting in an overall reduction of the building’s total thermal load by 7.56%. With Sketch 1, the heating load dropped by 19.52%, while the cooling load rose by 17.47%, leading to an overall decrease in the building’s thermal load by 1.73%. Given that using an atrium increases the window-to-wall ratio, a concurrent reduction in heating load and increase in cooling load is expected. Based on the building’s total thermal load, Sketch 2 is ultimately recommended as the optimal atrium design for this building. Implementing an atrium according to Sketch 2 would lead to a 7.56% reduction in the building’s total energy consumption.