Profile: America's Best Choice of Atlanta specializes in providing replacement windows. Single-hung windows have one bottom vertically sliding sash. The top sash is fixed. Casement windows have one main sash that uses a side hinge to crank out 90° for peak ventilation. Sliding glass doors have two or three panels with one panel that slides. Swing doors come in many variations such as in-swing, out-swing, single operation and double operation swing doors.