Comparing window specs fairly
The cheapest quote is rarely the worst window, and the dearest is rarely the best. The only way to know is to line up quotes on the same specifications — so you are comparing like with like, not price against product. Here is the method pros use.
Why raw prices mislead
Two quotes for “the same” job can differ by hundreds of pounds simply because they describe different windows. One might use a five-chamber frame, laminated glass and a whole-window U-value of 1.2; another a basic profile, air-filled units and 1.6 — both labelled “double glazing”. Compare the totals alone and you reward the corner-cutting. Compare the specs and the real picture appears.
Normalise before you compare
Put every quote onto the same footing first. Line up these rows for each one:
| Row to normalise | Make sure each quote states… |
|---|---|
| Scope | Supply and fit, same number of windows and styles |
| Glass make-up | Coating, gas fill and spacer, not just “A-rated” |
| U-value | Whole-window, never centre-pane |
| Frame | Profile, chamber count and reinforcement |
| Security | PAS 24, locking and any laminated glass |
| Fitting | Removal, disposal and making good included |
| Guarantee | Length, certification, insurance backing |
Missing cells are as revealing as filled ones. If a quote cannot state its whole-window U-value or its glass build, that is information in itself. Our guide to reading a technical window quote shows where to find each figure.
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Once the rows line up, a fair comparison is simple: for a given specification, which installer offers the best price, guarantee and reputation? A quote that is dearer but delivers a lower U-value, laminated security glass and a longer insurance-backed guarantee may be far better value than a cheaper, thinner spec. Equally, you should not pay a premium for features you do not need — a third pane where double vs triple glazing specs shows it adds little, for example.
Beware the false economy and the hard sell
Two traps catch buyers. The first is the false economy — a low price hiding a “supply only” scope or a budget frame that will underperform for decades. The second is pressure selling: a “today only” discount is a tactic, not a saving. A genuine quote holds for a reasonable period and stands up to comparison. Take your time; the specifications do not change if you sleep on it.
Widen the picture
Fair comparison also means understanding the market. It helps to compare glazing types side by side so a like-for-like uPVC comparison is not accidentally pitched against aluminium or timber, and to weigh how you collect quotes — there are real differences to getting window quotes online versus in-home. Cross-check the fundamentals in the window specifications hub or revisit the grading system in window energy ratings A to G before you decide.
Compare fairly, decide confidently
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