Three Quotes, Three Prices: Why the Same Window Costs Twice as Much

Article

October 26, 2026

Three suppliers, three quotes, one window — and the prices differ by a factor of two. The instinct is to conclude that two of them are overcharging, or that one of them is cutting corners. Usually neither is true. What differs is what each quote actually contains, and the only way to find out is to take them apart in the same order.

The evidence below comes from buyers describing their own projects in procurement forums. Those accounts are self-reported and not independently verified, and they are used here for the shape of the spread rather than as measured fact.

This article sets out the five places the difference comes from, gives the one question that separates each of them, and ends with a grid that will normalise three quotes in about twenty minutes.

Five Places the Difference Comes From

Every price gap between two quotes for “the same window” comes from one of five places, and they are worth checking in this order, because this is roughly the order in which the differences get large:

1. Scope — what is included at all.
2. Glass — the make-up hidden behind the words “double glazed”.
3. Hardware — grade, locking points, brand.
4. Installation — and what “installation” covers.
5. The chain — how many hands the order passes through before it reaches a fabricator.

The first two usually explain the larger part. The last one explains the gaps that look irrational.

Scope First, Then the Glass Inside It

One buyer describing a project in Germany reported component-only quotes of EUR 13,000 and EUR 22,000–25,000 for the same scope, while quotes that included installation ran from EUR 17,000 to EUR 40,000. The account is self-reported and unverified, but the shape of it is the instructive part: the supply-only spread was under two to one, and the installed spread was more than two to one. Adding installation to a comparison does not merely raise the number — it widens the range, because installation is priced by local labour and local practice, not by the factory.

The second reason sits inside the first line of the specification. “Double glazed” covers a spread of its own: a plain air-filled unit, the same unit with a Low-E coating and argon, the same again with a warm-edge spacer, and a laminated build where the situation requires it. On a mid-range unit that spread alone can reach 30 to 40 % of the glass line, which is a quarter of the window.

This is the point at which a supplier ought to be honest about the limits of its own product. Our standard build is 5 mm + 20 A + 5 mm double glazing, with a U-value of 1.8 W/(m²·K) or lower. If one of your three quotes is for triple glazing, that quote is for a different product — thermally better, and not something we will pretend to match. The useful move is to compare the double-glazed quotes with each other and treat the triple-glazed one as a separate decision about budget, not as a price to beat.

Hardware Grade, Which Photographs Cannot Show

Hardware is 10 to 18 % of a window price and it is the line buyers inspect least, because the visible part — the handle — looks nearly identical across grades.

Three things actually differ. Locking points: a three-point lock and a seven-point lock are the same in a photograph and are not the same product. Hinge count against sash weight: a heavy sash hung on the minimum number of hinges will sag, and the sag shows up two years later as a draught along the closing edge. Brand versus “branded”: “German hardware” names a country, not a product; a quote that cannot name the model has not specified anything.

None of this is visible on delivery either. It becomes visible at the first winter, which is why it belongs in the comparison rather than in the complaint.

What “Installation” Means in Each Quote

What installation covers varies more than the windows do. One buyer in Ireland reported a project where installation was promised in two to three weeks and took twelve, with drilled holes breaking glass and debris left between the units. That account is self-reported and unverified; the mechanism it describes is not unusual, because installation is the part of the job that gets subcontracted, scheduled last, and priced on the assumption that nothing goes wrong.

Two quotes can both say “installed” and differ by 40 %. The five questions that resolve it are: are the old units removed, are the reveals made good and with what, is the internal sill included, is waste removed from site, and is access equipment included and arranged by whom. Each missing answer is a cost that reappears later at a worse price.

A supplier who answers those five questions before being asked is telling you something about how the job will run. A supplier who answers them only after the third email is telling you something too.

How Many Hands the Quote Passed Through

The last reason explains the gaps that look irrational — where one quote is so far above the others that no product difference can account for it.

A buyer in Cape Town reported quotes for the same aluminium windows ranging from about R15,000 to R70,000. In one case, according to that account, the R70,000 quote was passed to a fabricator at R30,000. If the account is accurate, the product was the same product. What the extra R40,000 bought was a layer.

This is not automatically bad. A layer can buy a single point of contact, a warranty enforceable in your own jurisdiction, someone to chase when something is late, and someone to absorb the risk of a bad installation. Those are real services with real costs. But you should know that you are buying them, and roughly what they cost — which is exactly what the R15,000-to-R70,000 spread makes visible.

The tell is simple: ask who fabricates the units. A supplier who will not name the factory — or who names a brand rather than a plant — is selling a layer. That may be what you want. You should still be able to see it.

One Question That Separates All Five

Ask every supplier the same thing: can you re-quote this exactly as it stands, once supply-only and once supply-and-install, with the exclusions listed in writing?

A supplier who can do that within a day has a real cost model. A supplier who cannot is either quoting from a price list or unwilling to show the seams — and in both cases the number you are comparing is not a price, it is a position.

Ask a second question while you are there: from which event does the lead time run? Order, deposit and drawing approval are three different starting guns, and three quotes can all say “six weeks” and mean three different dates. Our own figure is 25 to 35 days from shop-drawing approval, which is production time and not door-to-door — a distinction that matters when you are planning a site.

Normalising Three Quotes in Twenty Minutes

Fill this in once for each quote. It takes about twenty minutes, and the three numbers stop being comparable in the wrong way and start being comparable in the right one.

Two rules for reading it. Compare only rows where every quote has an entry. And treat a blank as a question, not as a zero — a missing line is information about the supplier, not a saving.

Our own position, stated plainly: we quote within one business day from drawings and quantity, itemised, with a single unit as the minimum order. We do not install, and there is no local installation network behind these units. A supply-and-install comparison is therefore one we will always lose, which is why we would rather you compared us on the supply-only line — where the comparison is real and where the numbers can be checked against each other.