Windows · Buying
Compare window quotes
Two quotes for the same windows are rarely quotes for the same thing. One takes out the old frames and the other does not; one states the Uw and the other only says “double glazing”. Type each quote in as it is written and this page puts them on one footing: price per m² of window and per window on the same VAT basis, the Uw side by side, and every item a quote leaves out or does not mention, flagged and turned into a question for that company. It does not pick a quote for you: it shows where they differ.
Example: three made-up quotes.
What differs
Side by side
Questions to ask each company
Everything runs in your browser. The quotes are kept in this browser only. A link to them carries the quotes inside the address itself: whoever has the link can open them, and no server keeps a copy.
How the comparison is made
One VAT basis. When the quotes state VAT, prices are compared with VAT, which is what you pay. A quote “plus VAT” is converted with the rate it states itself: price × (1 + rate / 100). A quote that does not say whether VAT is included, or that would need a rate it does not give, stays out of the price comparison until you fill it in; the page never assumes a rate.
The same windows. The area is Σ width × height × quantity of the windows in the quote, in m² (sizes in mm). If the quote only gives a total area, that is used. Price per m² = price / area; price per window = price / number of windows. A quote with fewer windows than another, or with as many windows but more than 5% less area, is flagged: companies measure the opening or the frame, and a missing window makes a quote look cheap.
The differences. “B costs 18% less than A” means (A − B) / A × 100, both per m² on the same VAT basis. The verdict names how far apart the prices are and what the cheapest quote does not include, or does not state, that another one does: removal, fitting, sealing and trims, sills, disposal and the Uw.
Not stated is never zero. An empty field is “not stated” everywhere on the page, never “included” and never 0. Each one becomes a question for that company, and so does each item a quote leaves out. Everything a quote states is shown as written; nothing is checked against the company.
The example, worked by hand
Six windows: 1500 × 1400, two of 1200 × 1200, 1000 × 1100, 600 × 600 and a balcony door of 900 × 2100 mm, which add up to 2.10 + 2.88 + 1.10 + 0.36 + 1.89 = 8.33 m². Quote A: 6,200 with VAT, so 6,200 / 8.33 = 744 per m². Quote B: 4,200 plus VAT at 21%, so 4,200 × 1.21 = 5,082 with VAT and 5,082 / 8.33 = 610 per m². Quote C states 8.40 m² and 5,700 with VAT: 679 per m². B costs (744 − 610) / 744 = 18% less than A per m², but it leaves out removal and sills and states no Uw. The quotes and the companies are made up.
What this page does not do
- It does not know prices. Nothing here says what a window should cost: there are no typical prices in it, only the quotes you type.
- It does not check the companies' figures. A Uw is compared as written. Whether it is the declared value for the standard size (EN 14351-1) or one worked out for your windows changes it, which is why it is one of the questions. The window U-value calculator works out Uw from the glass, the frame and the spacer.
- Per m² is a fair yardstick, not an exact one. Small windows cost more per m² than big ones, and opening sashes, doors and special glass cost more than fixed panes. Compare per m² between quotes for the same windows, not with another house.
- Five inclusions are compared. Removal, fitting, sealing and trims, sills and disposal. Scaffolding, shutters and roller boxes, permits, plaster and paint are not listed: ask about them if your job needs them.
- It does not choose. Price, guarantee, Uw, lead time and what you know of each company weigh differently in each home.
How do you compare quotes for new windows?
On the same basis: the same VAT treatment, the same windows (the sizes should add up to about the same area) and the same inclusions. Then the price per m² of window is a fair yardstick, and what is left (frame, glass, Uw, guarantee, lead time) is what the difference pays for. What a quote does not mention is asked, not assumed.
What should a quote for new windows say?
The size and number of windows, the frame material and profile system, the glazing make-up, the Uw, the spacer bar, whether removal, fitting, sealing and trims, sills and disposal are included, the guarantee on frames, glass and fitting, the lead time and whether the price includes VAT. Each of these is a field above; anything a quote leaves blank becomes a question.
Why compare price per m² and not the total?
Because two totals rarely cover exactly the same thing. One company may have measured the opening and another the frame, or left out a window. Dividing by the area of the windows each quote actually prices puts them on the same footing, and the page flags it when the areas or the number of windows do not match.
What does the Uw of a window tell me?
How much heat goes through the whole window, glass and frame together, in W/(m²·K): the lower it is, the less heat the window loses. It is always worse than the Ug of the glass alone because of the frame and the edge of the glass. The window U-value calculator shows how frame, glass and spacer add up.