Double glazing window replacement cost: what the job involves and who is registered to do it

How double glazing window replacement cost works

1. Diagnose the frame before pricing the window. Open and close every sash. A frame that binds, that has to be lifted on its hinges, or that shows daylight along a closed seal has moved. Test timber at the bottom rail and the cill with a blunt point. If the frame is sound and only the glass has misted, you are buying sealed units and the rest of this is not your job.
2. Price the units separately where they can be. Sealed units are made to measure and fitted into the existing frame with new beads and gaskets. It is a glazier's visit rather than an installation, and asking for it as its own quote stops it being folded into a whole house price you did not need.
3. For real replacement, schedule the whole run. If the frames are going, price every opening in the run at once. Doing a house in stages costs more in fixed visits, and it leaves you matching a profile and a colour to something bought years earlier, which manufacturers change more often than homeowners expect.
4. Budget the making good. Old frames rarely come out cleanly. Expect internal plaster damage at the reveal, expect the cill to need attention, and expect external sealing. Whether the installer does this or leaves it for you is the largest hidden difference between two quotes for the same windows.
5. Keep the certificate with the deeds. Registered installers issue a certificate for notifiable work. It is asked for at the point of sale and reproducing it years later is harder than filing it now, so put it wherever the boiler paperwork and the electrical certificates already live.

Insurance and paperwork

Common questions

How do I know if it is the unit or the window that has failed?

Misting or water between the panes is the sealed unit and only the unit. Draughts, difficulty closing, water inside the room, or a frame that has visibly dropped is the window. The two problems look nothing alike once you know which you are looking at.

Can I replace one window to match the others?

Usually, if the system is still made and the colour is still available. Profiles change, so ask the installer to check the match before ordering rather than after, and be prepared for the closest match rather than an identical one.

Is replacing double glazing with triple glazing straightforward?

It is a new window rather than a new pane, because the sealed unit is thicker and the frame has to take the weight and the depth. Treat it as a replacement window decision, not a glass upgrade.

Registered contractors by region

• Registered roofers in the East Midlands postcode area
• Registered roofers in the East of England postcode area
• Registered roofers in the London postcode area
• Registered roofers in the North East postcode area
• Registered roofers in the North West postcode area
• Registered roofers in the Scotland postcode area
• Registered roofers in the South East postcode area
• Registered roofers in the South West postcode area
• Registered roofers in the Wales postcode area
• Registered roofers in the West Midlands postcode area
• Registered roofers in the Yorkshire and The Humber postcode area