A window system for use in windows, sliding glass doors, skylights, casement windows and other openings in a building. The window system enables different windows of the same building to be individually customized for different impacts of coastal area weather and security concerns and also have the same external appearance despite employing various window protection steps. Panels, interior or exterior, are secured to the header and sill. Windows may be covered with exterior panels or include interior panels or impact resistant glass when the window is high on the building, or where security is a concern Windows including casement windows and other building penetrations may also accommodate interior panels, in combination with exterior protection. The window framing may have a uniform exterior appearance, notwithstanding different levels of protection.