Twenty years on the tools
I have spent more than two decades fitting windows and doors in homes across the country, from terraced houses needing a like-for-like swap to full replacements on period and detached properties. That means I have seen what a casement, a sash or a bay window really takes to remove, supply and fit properly, and what it should cost. The prices on this site are not guesses: they are checked against the day-rate reality of the work, then cross-referenced with the published 2026 cost guides.
Why I built this
Over the years I lost count of the customers who showed me a quote from a national firm for two or three times what I would charge for the same specification. The pressure selling, the "today-only" discounts, the vague spec sheets: I had seen all of it from the inside. So I put together the numbers I wish every homeowner had before they let a salesperson through the door. If you read one thing first, make it my guide to avoiding overcharging, then run your figure through the quote checker.
What I will never do
I do not sell windows through this site, I do not take a commission from any installer, and I do not sell your details as a lead. There is no version of this site where I earn more by telling you to spend more. That independence is the whole point. You can see exactly how the figures are put together on the methodology page, or put a number to your own home with the calculators.
A window is a half-day job done right. When I see a quote that assumes a full day per window, or hides the glass spec, I know exactly where the money is going, and it is not into your home.
Tom Bradley, FENSA-registered installer
Getting it right
I write every page here and check the prices for sense before they go live. Window costs and grant rules move, so I keep the figures dated and refresh them when the major cost guides publish new editions. If you think a number on this site is off, tell me, because the only thing this site sells is getting the numbers right. Read more about how the site works, or start with the 2026 cost guide.