So, why are UPVC windows still the biggest selling type of replacement window in the UK. Well, I think the answer is pretty easy really it’s mainly down to price against insulation value. If you compare UPVC windows to any other type of replacement windows you will find them hard to beat when you price up the energy saving against the cost of installing the windows. Most of the window fitters who come into our window trade counter in Harleston buy and fit plastic (UPVC) windows because the client has specified them. But even when the fitter has offered an alternative most window consumers (the public) still go for UPVC windows. Maybe one day it will be different but for now the figures say loud and clear… Plastic Window are King.