Buying · 6 min read · Updated 2026
How to compare window and door quotations properly
Most people collect three quotations and then discover they cannot be compared, because each describes something different. Here is how to normalise them.
Ask every quotation to state the same eight things
If a quotation is missing any of these, ask for it in writing before you decide.
- The profile system and manufacturer, by name
- Whole-window U-value or Window Energy Rating
- Glass make-up, including spacer type and gas fill
- Colour inside and out, plus texture or foil reference
- Hardware make and finish, and the security standard achieved
- Whether the installation is PAS 24 / Secured by Design compliant
- Exactly what making good is included — internal plaster, external silicone, cills, trims
- The guarantee: length, what it covers, who underwrites it
Red flags
Discounts that only exist today. Prices that drop dramatically when you hesitate. Pressure to sign at the kitchen table. Quotations that name no product system. Deposits well above a third of the value.
None of these tell you anything about the quality of the windows — they tell you about the sales model.
The questions worth asking
Who will actually fit the windows, and are they employed or subcontracted? What happens if a frame is damaged in transit? How is the job certified for Building Regulations? What is the lead time, and what happens if it slips?