Name: Window World Of Utah. Descripton:Window World of Utah is a family run licensee of Window World Inc. Owned and operated by Kathy and Doug Llewellyn, we are Utah's leading window replacement company! To better serve our replacement window customers, we have 2 locations, in Salt Lake City and Spanish Fork, serving the great state of Utah. Our objective is to provide you with the best vinyl replacement windows, doors, and vinyl siding at the lowest possible price.