u-pvc or pvc-u whats the difference.??

It is the same thing. uPVC changed it’s name to PVCu (you may also see it as PVC-U) in the late 1980s to fall in line with Europe. It is called PVCu there because most European languages place the noun (the word PVC in this case) before the adjective (U). The ‘PVC’ part of it stands for Polyvinyl Chloride. The ‘U’ stands for Un-plasticised.