This is a common misunderstanding of terms, as it’s entirely possible to have double and triple-glazing UPVC windows, as UPVC simply refers to the materials used in the frame of the window. UPVC windows are a popular choice due to their energy efficiency, durability and low maintenance. UPVC windows in Glasgow are a worthwhile investment due to their energy efficiency abilities – a key factor in the cold conditions of central Scotland – as well as their high levels of durability and low maintenance.