PVC Windows, PVCu Windows and UPVC Windows all refer to the same material and they are exactly the same. Their official name is PVC-U windows.
UPVC changed its name to PVC-U in the late 1980’s to be consistent with the rest of Europe. It’s believed Europe called it PVC-U because European languages mostly place the noun (being PVC in this case) before the adjective (U).
The U stands for Unplasticised and PVC stands for Poly Vinyl Chloride. Commonly referred to as PVC, many people are aware of this material because of its use for many typical products such as bags, shoes and faux leather.
In order to be used for the manufacturing of windows and doors, pure PVC-U needs a small number of additives to ensure longevity, UV resistance and weatherproofing. Furthermore, the additives are also necessary for achieving the familiar white colour found on windows and doors.