Their windows come in essentially all styles used in home building. You can choose your replacement windows from 12 different product lines, all of which meet ENERGYSTAR® guidelines. Simonton provides options for grille patterns, hardware finishes, interior and exterior frame colors, even the type of glass used. Want triple pane windows? They will do that, too. Simonton windows and doors are made in Vacaville. The company is part of the PlyGem group within Cornerstone Building Brands, headquartered in Cary, North Carolina. Cornerstone Building Brands is North America’s leading exterior building products manufacturer.