Why It's Better to Repair Your uPVC Windows Instead of Replacing Them Repairing your uPVC window is often cheaper than replacing it. This is also more sustainable and will cause less disruption in your daily routine. Be sure that the window's bottom sash is properly in place against the frame. http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=1214438