Dormers are one of the best ways to expand the living space in your home without having to move. You may wonder exactly what they are? People use the term dormer to refer to different things: a converted upper-level room; a horizontal extension of a converted room; or a window in the room itself. A good way to recognize a dormer is to look at the pitch of a roof, and whenever you see any gabled windows rise from its surface, you are observing a dormer at work.