New windows are a once-in-25-years purchase, and that's precisely the problem. Nobody gets enough practice at buying them. The industry knows it too, and parts of it are built to exploit exactly that, with inflated 'discounts', pressure tactics and specifications that sound impressive while quietly cutting corners. After decades fabricating and fitting windows across Greater Manchester, we've watched every mistake below walk through our door, usually attached to a story that begins 'the last company said...'.
These are the ten that cost homeowners the most, in roughly the order they tend to happen.
1. Buying on price alone
The cheapest quote is cheap for a reason. Unreinforced frames, cold-edge spacers, bottom-tier hardware, subcontracted fitting. The bitter economics turn up later, as failed units at year five and a company that no longer exists at year six. The right comparison isn't price. It's price per year of honest service, and a £550 window lasting 30 years beats a £400 window lasting 12, twice over.
2. Falling for the fake discount
'£12,000, but if you sign tonight, £6,500.' No legitimate manufacturer halves their price for a signature. The real number was always £6,500, inflated purely to manufacture gratitude. Any offer that expires when the salesperson leaves is a red flag, full stop. Never buy windows from someone who won't put the quote in writing and let you sleep on it.
3. Ignoring the whole-window U-value
'Energy efficient glass' is only half a claim, because heat escapes through frames too. Insist on the whole-window U-value or WER rating for your actual sizes, and look for 1.2 W/m²K or better, A++ where possible. Our energy ratings guide decodes the labels in five minutes.
4. Forgetting security specification
Two windows can look identical while one meets PAS 24 and the other pops open with a screwdriver. Multi-point locking, internal beading and laminated-glass options make the difference, and we've spelled them out in our window security explainer. If a quote doesn't mention PAS 24, ask why not.
5. Skipping the paperwork questions
Every replacement window in England needs building-regulations sign-off, evidenced by a FENSA-type certificate that a buyer's solicitor will one day demand to see. So ask who certifies the work and when the certificate arrives. 'Don't worry about that' means worry about that. The mess it causes is laid out in our FENSA guide.
6. Choosing style for the brochure, not the house
Anthracite flush casements photograph beautifully, on the right house. On a Victorian terrace they can fight the architecture and, in conservation areas, fail planning altogether. Match the window to the building. Heritage styles for period streets, slim modern frames for contemporary ones. Our window trends guide covers what suits what.
7. Ignoring ventilation and escape rules
Trickle vents are now required in most replacements, and refusing them invites the condensation problems that ruin reveals. Habitable first-floor rooms need escape-compliant openers too. A beautiful window you can't climb through is a regulation failure waiting for a surveyor to spot it.
8. Not asking who actually makes the windows
Plenty of 'manufacturers' are really sales offices reselling frames from a factory they've never set foot in, with a margin stacked on for the showroom and the commission. Buying from the actual fabricator strips that layer out, typically 20-30% on identical specification, and it means the guarantee sits with the people who built the frames. See how our windows are made in Trafford Park.
9. Neglecting the installer's track record
A perfectly manufactured window fitted badly leaks around its perimeter forever. Ask who physically does the fitting. Employed teams, or whoever answered a subcontract ad this month? Ask for local addresses you can drive past. Ten minutes reading reviews that mention 'aftercare' and 'came back' tells you more than any showroom ever will.
10. Replacing what should be repaired (and vice versa)
Both errors cost real money. A misted unit in a sound 12-year-old frame needs new glass, not a new window, while a warped 28-year-old frame needs replacing, not its fourth hinge. Our repair-first policy exists because the right answer genuinely differs house by house, and the signs are catalogued here.
The five-question filter
If you remember nothing else, put these five to every bidder. What's the whole-window U-value on my sizes? Is it PAS 24 certified? Who manufactures the frames, and where? Who certifies building regs compliance? Who holds the guarantee, and what exactly does it cover? Honest suppliers answer each in a sentence. Everyone else is telling you something too.
One last habit worth adopting. Write down what you were promised. Specification, colours, hardware, timescales, guarantee terms, all in the quote rather than in conversation. The overwhelming majority of window disputes we hear about aren't fraud; they're two mismatched memories of a kitchen-table chat six weeks earlier. A supplier confident in their promises will happily put every one of them on paper, and simply asking quietly filters out the ones who aren't.
Frequently asked questions
How many window quotes should I get?
Three is the sweet spot, ideally a national brand, a local installer and a fabricator. You'll see the price spread, often thousands for the same spec, and the specification differences that explain it. More than four quotes usually adds confusion rather than clarity.
What questions should I ask a window company?
Whole-window U-value on your sizes, PAS 24 certification, where the frames are manufactured, who does the fitting, who certifies building regs, and the exact guarantee terms. The pattern across the answers matters more than any single one.
Are window sales discounts genuine?
Time-pressured ones almost never are. The 'discounted' figure is the real price with theatre attached. Genuine seasonal offers survive being slept on, and any company that won't leave a written quote valid for 30 days is negotiating against you.
Is it cheaper to buy windows direct from a manufacturer?
Usually 20-30% against sales-led national brands, for equal or better specification, because there's no commission layer. You also get direct accountability, since the people who made the frames are the ones honouring the guarantee.
When is the best time of year to buy windows?
Spring and summer bring shorter lead times and unhurried surveys, while autumn is the industry's rush. Fitting itself works year-round, as each opening is only exposed for under an hour.
Should I pay a large deposit for windows?
Made-to-measure products justify a fair deposit, typically 25-50%, but be wary of demands for most of the money upfront, and check whether deposits are insurance-protected. Never pay the balance before installation is complete and snagged.
Get a quote that answers the five questions before you ask them
Every Prime Fabrication Windows, Doors & Glazing quote arrives with the U-values, PAS 24 certification, factory address (ours, in Trafford Park), certification route and 10-year guarantee terms in writing. No evening salesmen. No expiring discounts.
Call 07533 830717, WhatsApp us a photo for a fast quote, or request a free quote online.