Bay windows protrude from an exterior wall and create a small shelf in the home. Bay windows rely on flat windows set into an angled frame that are built out of the home. A bay window costs more to install as it is a larger window that requires a skilled installer. The average cost to install a bay window could be anywhere from $1,150 to $3,550. This usually consists of a center window, from which two side windows are angled at 30 to 40 degrees.
