There are several types of windows commonly used in buildings, each serving different purposes. Single-hung windows have a fixed top sash and a movable bottom sash, allowing for ventilation. Double-hung windows feature two movable sashes, providing more airflow options. Casement windows are hinged on one side and open outward, offering excellent ventilation and unobstructed views. Sliding windows consist of two or more sashes that slide horizontally, making them easy to operate. Lastly, bay and bow windows extend outward from the building, creating additional space and enhancing natural light.