The actual cost of uPVC windows depends on several factors, including the size of the window and your choice of glazing. Many uPVC window sites have a dedicated uPVC windows price calculator – all you need to do is take some measurements and then plug in some other details, such as the number of panes or openings and whether the window is for the first or second floor. The choice of brand affects the cost, as does the window hardware you choose to complete the units.