What is involved in making a window larger?
To make a window taller, or come closer to the floor, you will need to do some re-framing. But it usually does not require altering the load bearing, or structural part of the framing. In order to make a window wider, you will have to change the header of the window. This is much more involved because the roof or second story will have to be held up while the header is being replaced (the header is the framing that usually holds up the roof or second story). Obviously, to widen a window, is going to cost more than just making a window taller.