In the BPF's own guidelines, they identify low maintenance as being a major benefit of PVC-U windows. We recommend regular cleaning with appropriate detergents and warm water, and the checking of certain hardware components such as gaskets and hinges, which may need lubrication from time to time. This would hold true for all materials, however, and is not unique to PVC-U.
In a report undertaken by the German Institute for Construction with Plastics on behalf of the German Federal Ministry for Environmental Planning, Construction and Urban Development, the long-term characteristics of PVC-U were identified as follows: "Faults on windows using PVC-U profiles occur usually in the operating mechanism or the seals, i.e. the components that are not made of PVC.
Hence the long term characteristics are determined by the durability, low maintenance and wear characteristics of the components installed into the PVC window frames, and not by those of the frame itself. Since the PVC window frames do not have to be painted with fungicides or protective coatings, no maintenance of the frame is required apart from cleaning".
PVC-U can be successfully maintained by following the guidance provided by the British Plastics Federation's Windows Group. It is important to remember that timber window frames are also subject to weathering, and they will require cleaning just the same as PVC-U. PVC-U windows, however, do not rot, warp, peel or chip.