Nowadays, with the intensification of environmental crises, attention has been paid to approaches such as green buildings and buildings Energy Retrofit. Including educational buildings that consume a lot of energy and environmental quality is very important to them. In this study, to improve the building of a school under construction in Gorgan with the green building approach, two strategies for improving the building envelope and fenestration and shadings have been studied and compared. In selecting improvement strategies, reducing energy consumption and cost have been the basis for comparing the solutions. The research methodology was based on simulation and descriptive-analytical approaches.Firstly, the base model of the building was made in DesignBuilder software, and then various options for improving the building envelope and modifying fenestration and shadings were modeled. These options were determined based on previous studies and technical and economic conditions and were limited to a few options. The results and outputs of energy consumption and daylighting were reviewed and compared and the best options were identified. Based on the results, window dimensions and the addition of shading devices contribute to approximately a 27% reduction in energy consumption. In comparison, enhancing the building envelope and increasing insulation result in about a 3% reduction in energy consumption. In economic comparison, this option has a lower priority than improvement fenestration and shadings. The results of this study indicate the importance of fenestration and shading design, especially in educational buildings in temperate and humid climates compared to the building envelope.