Which type of window has a side-hinged sash that swings inward or outward?

The casement window features a side-hinged sash that can swing either inward or outward, depending on how it is designed and installed. This type of window allows for excellent ventilation since it can be opened wide to capture breezes effectively. Additionally, when fully opened, casement windows provide an unobstructed view, making them popular in various architectural styles.

Casement windows operate with a crank mechanism or a simple handle, which enhances their functionality and ease of use. The hinge on the side allows the sash to open outward and catch the breeze, promoting airflow into the home.

Stationary windows do not open at all, thus lacking the function of ventilation or airflow. Double-hung windows, while they do provide operability, feature two vertically sliding sashes instead of side-hinged sashes. Hopper windows, typically used in basements or as transoms, swing inward and are specially designed for easier ventilation in tight spaces. However, they do not meet the criteria of being primarily side-hinged like casement windows. This clarity of function and design makes the casement window the correct answer to the question.