Abstarct: The energy crisis and the need to improve energy efficiency in buildings have increasingly highlighted the importance of utilizing renewable technologies. One such technology is solar greenhouses, which help reduce energy consumption for heating and cooling by capturing and storing solar energy, thereby enhancing the thermal performance of buildings. This study investigates the performance of a solar greenhouse connected to a residential building in the cold and semi-arid climate of Shahrood city. To analyze and simulate the energy performance of the building, DesignBuilder software (version 6.1) was used. Various parameters, such as solar greenhouse depth, type of glass, thermal mass, and roof angle, were examined in the simulation. The results showed that the baxse building (without a solar greenhouse) consumes 4322.5 kWh of energy annually for heating and 2918.1 kWh for cooling. By adding a solar greenhouse to the southern facade of the building, with specifications such as a 2-meter depth, double-glazed glass with argon gas, 10 cm of thermal mass, and a 90-degree roof angle, heating energy consumption decreased by 24.1% and cooling energy consumption by 5.3%. Furthermore, further investigations revealed that increasing the greenhouse depth to 2 meters, using triple-glazed glass, increasing the thermal mass to 20 cm, and adjusting the roof angle to 45 degrees could lead to the most optimized system performance, resulting in even greater energy savings.