This type of window has two sashes. The first sash is found at the bottom, and it moves vertically while the other one is found at the top and it doesn’t move. When single hung windows are contrasted with fixed windows which consist of one sash that cannot move, or double hung windows that have two sashes that both have the ability to move up and down; a great difference can be clearly seen.
It is possible to find single hung windows in both replacement and construction window styles. The main advantage of a fixed window is that it limits air intrusion. This is because it has fewer seams that should be blocked by the use of window seals. With time, window seals get dry and hard. This creates cracks that allow for air seepage. Also, some fixed windows are less expensive compared to casement windows or double hung. This is due to fewer mechanical parts.