A hopper window is hinged at the bottom. These windows are designed to open inward to a point completely perpendicular to the wall, allowing for maximum ventilation in basements or small spaces like bathrooms. What makes the hopper window versatile for small spaces is the fact that they open completely. A smaller window occupies a limited amount of space already and those that slide open only allow half the area of the window to be used for ventilation. A hopper window, because the entire window opens from the top, allows ventilation through the entire surface area of the window. It is, therefore, commonly found in basements and in bathrooms where there is a window in the shower or tub area. Though less common, they are sometimes used above other, larger style windows.
The hopper window features a hinged bottom and a locking mechanism at the top. There is a small, lever-style handle that is used to open and shut the window that also fits into the locking mechanism for security. Depending on the size of the window, security features are important because of the fact that the window is often at or close to ground level, making them easily accessible for intruders.