A double glazing quote is hard to read until you break it down to a per-window figure. This auditor does that for you: enter the number of windows and the total fitted price, and it works out the cost per window and flags it against the fair 2026 band of £400 to £1,000 for a uPVC casement. It is a sanity check, not a verdict on the installer, but it tells you quickly whether a quote is in the right ballpark, suspiciously cheap, or on the high side.
How the benchmarks work
The fair band comes from 2026 fitted prices cross-checked across Checkatrade and installer guides. A uPVC casement runs £400 to £1,000 per window fully fitted, which covers supply, labour, removing the old window, sealing and the FENSA certificate. Anything well below that band usually signals a missing element, often that the figure is supply-only or excludes VAT. Anything well above it should be matched to a reason: sash and bay styles, timber frames, large openings, upper floors or a premium glass specification.
What a per-window figure does not tell you
Price per window is the fastest filter, but it is not the whole story. A cheap quote with a 10-year guarantee and a clear A-rated specification can be better value than a mid-priced one with vague paperwork. Always confirm the frame material, the glazing rating, the guarantee length and whether the installer is FENSA-registered. A quote uses that vocabulary without stopping to explain it, and terms such as WER, uPVC and FENSA are defined in a line each in our double glazing glossary, so check anything unfamiliar against the Double Glazing Glossary before you accept that a quote is complete. If a quote passes the per-window check but the sales approach feels pushy, that is its own red flag. For a full whole-house benchmark by property type, see our cost by house size guide.
Frequently asked questions
For a fully fitted uPVC casement window, the fair range in 2026 is £400 to £1,000 per window. Around £650 is typical. Below £400 is suspiciously cheap and worth questioning, while above £1,500 is high unless the window is timber, sash or a bay.
Be careful. A price under £400 per window for a fully fitted uPVC casement is below the fair band, so check exactly what is included. It may be supply-only, exclude VAT, leave out removal of the old window, or use a thin specification without an A-rating or FENSA certificate.
A figure above £1,000 to £1,500 per window can be fair for sash, bay or large windows, for upper floors needing scaffolding, or for a premium glass specification such as acoustic or triple glazing. Ask the installer to itemise what the extra buys you before you accept it.