To find the best double glazing prices for windows or doors, it is useful to compare quotes from different installers. By comparing the price of double glazing online, you can save up to 50% on what you might otherwise have paid. To find out how much double glazing costs for you, whether you're looking for a single window or a whole house, you can compare double glazing prices online. As a rough guide, the average price of double glazed windows for a three-bedroom house is around £4,000.