What a window quotation should include

Frame material and system, opening style, colour and finish, glass specification, hardware, and what the installation covers. It should also state what happens to the old frames and whether making good is included. A single total with no breakdown cannot be compared against anything.

Compare specification before price. Differences usually come from the glass build-up, whether aluminium is thermally broken, the hardware grade, reinforcement, and how much of the finishing work is included. Two quotes for the same opening can describe substantially different products.

Commonly the finishing work: removal and disposal of old frames, making good to render, plaster or tiling, and any external sealing. Glass specification is another frequent difference, since a basic sealed unit and a solar-control unit can look identical on paper.

Yes. Pane thicknesses, cavity width, any coating and any lamination all change performance and cost. "Double glazing" alone does not describe what is being supplied and makes comparison between quotations impossible.

Made-to-measure windows are manufactured for one opening and cannot be resold, so a deposit is normal practice. What matters is that the amount, the payment stages and what each stage covers are stated in writing before the order is placed.