Mainly this research paper investigates passive systems used for buildings. Heating, ventilation, and air conditioning were the major energy consumers in the building industry globally. Due to its proximity to the equator, Sri Lanka has high average temperatures. Therefore, suitable ventilation and daylighting systems must be considered while designing a building or any other type of structure. Natural ventilation and passive cooling have received attention due to the growing contribution of ventilation and air conditioning to the overall energy consumption of buildings. Courtyard passive system used for proper ventilation in old houses as well as modern building designs. In addition, Passive stack ventilation is a widely popular natural ventilation method in residential structures. This method for various applications in buildings is environmentally sustainable. The stack effect caused by the temperature difference between the air inside and outside a building drives passive stack ventilation. A solar chimney & courtyard are some ways to enhance passive ventilation on hot, sunny days when there is a slight temperature differential between the internal and external air. Also, to get good passive lightning from sun. Therefore, this report discusses different types of passive systems and the application of solar chimneys to passive cooling & courtyard systems inside buildings.