For those with a keen eye for detail, our Heritage sliding sash uPVC window is, arguably, the most authentic-looking uPVC sliding sash window available on the market. Unlike most other uPVC windows, the Heritage is hand-built using mechanical joints to replicate the traditional mortise and tenon method of timber windows. The Heritage comes, as standard, with an authentic-looking white woodgrain foil, but is available in any RAL colour.