Average Double Glazing Prices – Double Glazing Cost in South West Mid Glamorgan Wales from your local company Fensa registered supplying and fitting HQ uPVC Double glazing near you with the very best prices quotes and low cost to you the customer and for your house and home. Average Price For New Windows In Wales double glazing costs can vary WHY? Depends on the frames colours and hardware to your preference choice and choices you make. There are many factors to consider which will affect the overall cost of double glazing.