Sash Window Products. Our uPVC sliding sash windows are ideal for those who own an older property or those who prefer traditional aesthetics. We offer an updated design that enables them to maintain the essence of the classic sliding sash window design without missing out on any of the modern innovations that enable them serve as a worthwhile investment for your home. Manufactured using an industry-leading profile, these windows are able to achieve an unrivalled standard of thermal efficiency, security, durability, weather proofing, longevity, functionality, and performance. When added to your home, they are sure to make it a safer and more comfortable place for you to be throughout the year. We use only German Engineered frames VEKA and extremely energy efficient glass units from Pilkington or Planitherm. All components used in our products are of the very highest quality.