Last Updated on September 8, 2026
Your customer has read a national cost guide. Possibly two. They disagree with each other by more than any negotiation you are about to have.
All figures below were read at source on 8 September 2026, with each page’s own last-updated date noted.
One window, four times apart
| Job | Figure | Publisher | Page date |
|---|---|---|---|
| Basic uPVC casement 600x900mm | £160 to £250 inc VAT | MyBuilder | 23 Dec 2025 |
| uPVC casement approx 1.2m x 1.2m, fitted | £350 to £600 | MyJobQuote | 9 July 2026 |
| uPVC casement, per window | £500 to £1,250, average £1,000 | Checkatrade | May 2026 |
| Sash window | £700 to £1,500, average £1,200 | Checkatrade | May 2026 |
| uPVC sash or sliding sash | £600 to £1,100 | MyJobQuote | 9 July 2026 |
| Tilt and turn | £600 to £1,400, average £1,100 | Checkatrade | May 2026 |
| uPVC tilt and turn | £400 to £700 | MyJobQuote | 9 July 2026 |
For essentially the same casement, MyBuilder’s ceiling is £250 and Checkatrade’s floor is £500. That is not a rounding difference. A customer who read MyBuilder believes your quote is double what it should be.
A three-bed house, with no overlap at all
| Property | Figure | Publisher |
|---|---|---|
| 3-bed house, 8 to 12 windows | £8,000 to £15,000 | Checkatrade |
| 3-bed semi, 10 to 15 windows, uPVC | £4,000 to £7,000 | MyBuilder |
| 3-bed semi, 6 to 10 windows, uPVC | £4,000 to £6,000 | MyJobQuote |
| Whole house average | around £4,500 | MyBuilder |
| Premium whole house | £10,000 to £15,000 | MyBuilder |
Checkatrade’s floor of £8,000 is above both other publishers’ ceilings. There is no overlap whatsoever between Checkatrade’s range and MyJobQuote’s on the headline number a homeowner googles.
One publisher contradicting itself
Checkatrade’s double glazing guide, dated May 2026, gives around £600 a day for two installers. Checkatrade’s window fitting guide, dated July 2026, gives £200 to £250 a day for a window fitter. Both pages were live on 8 September 2026.
The scaffolding figures on the same two pages are also incompatible: around £1,000 a week on one and £40 to £150 a day on the other. MyJobQuote publishes £300 to £800 per elevation.
The certificate cost, wrong by ten times
Checkatrade’s window fitting guide states that a FENSA certificate costs £25 per window.
FENSA’s own published fee schedule, document FSPF 53 issue 9, January 2025, puts the notification fee at £2.05 excluding VAT, £2.46 including, per installation. Not per window. FENSA charges homeowners £30 including VAT for a replacement copy of a certificate.
So the published figure is roughly ten times FENSA’s own per-installation fee, and it is attached to the wrong unit. It is the most concretely checkable pricing error we found in any consumer guide, and it is a number your customer may quote at you.
The one publisher naming a methodology
Which? publishes double glazing prices only to logged-in members, at £9.99 a month for digital access. Its page states that the Royal Institution of Chartered Surveyors uses cost data from its Building Cost Information Service database.
That is worth noting for a reason that has nothing to do with Which?. It is the only one of the four naming a professional cost database as its basis. The three free guides that disagree by four times name no methodology at all on the pages we read.
Composite doors, and a price that runs backwards
| Job | Figure | Publisher |
|---|---|---|
| Composite front door, fitted | £400 to £2,000 | MyBuilder, 21 Aug 2026 |
| Composite front door, no glass, supply and fit | £1,100 to £1,400 | Checkatrade |
| Composite front door with glass panel, supply and fit | £750 to £1,100 | Checkatrade |
| Any new front door, typical fitted | around £1,500 | MyBuilder |
Checkatrade prices a composite door with a glass panel below one with no glass, which is the reverse of how the product is normally priced. Its door installation guide is titled 2026 but its front door section carries a last-updated stamp of September 2024 and its internal doors section May 2024.
What to publish
- A per-window price for your most common product, stating supply and fit.
- One fully worked house: window count, product, scaffolding, waste removal, making good, days on site, total.
- Your day rate, if you quote labour separately at all.
- What is excluded. Scaffolding, waste, making good and lintel work are where quotes diverge.
- The correct certificate cost, with the source and the date, as a small public correction.
- A dated prices-checked line, reviewed quarterly.
Fewer than half of independent UK business websites publish any price at all, on Whito’s August 2026 study of 200 sites across ten trades and ten cities. In a category where the free national guides disagree by four times, publishing is not a risk. It is the only way to have the conversation on your own numbers.
Common questions
How much does double glazing cost for a 3-bed house in the UK?
The published guides do not agree and do not overlap. Checkatrade publishes £8,000 to £15,000, MyBuilder £4,000 to £7,000 and MyJobQuote £4,000 to £6,000, all live on 8 September 2026. Ask any installer what their figure includes, because scaffolding, waste and making good are where quotes diverge.
How much does a FENSA certificate cost?
FENSA’s published notification fee is £2.05 excluding VAT per installation, and a replacement copy for a homeowner is £30 including VAT. A national cost guide states £25 per window, which is roughly ten times the fee and attached to the wrong unit.
Why should an installer publish prices when nobody else does?
Because the customer arrives holding a number regardless. The only question is whether it is yours or a national average that may be several thousand pounds away from your quote in either direction.
The structural checks behind this research run on any website in about twenty seconds. Enter yours and read the full result on the page. Free, and we do not ask for your email.
Run the free Visibility Check