In 40 seconds
Most UK homes pay £400–£900 per uPVC window supplied and fitted, or roughly £4,000–£9,000 to replace all the windows in a typical 8–10 window house in 2026. Aluminium typically costs 30–50% more than uPVC, and timber is usually the most expensive. If a sealed unit has misted or “blown” but the frame is sound, replacing just the glass costs around £60–£200 per unit — far cheaper than a new window. Replacement windows are notifiable under Building Regulations, so the work should be done by a FENSA or CERTASS registered window installer, who self-certifies compliance and issues a certificate you will need when selling. Look for a good Window Energy Rating (A++ to E) or a low U-value, get at least three itemised quotes, and check that the certificate is included.