Your Window Guarantee Has Two Names on It — Make Sure Both Will Answer the Phone

A window guarantee is one of those things you only properly read when something has gone wrong. By then, the glossy folder is somewhere in a drawer, the fitter's mobile goes straight to voicemail, and you are squinting at a certificate wondering whether “ten years” meant anything at all. The good news is that most window warranties are not dodgy by default. The bad news is that plenty are thinner than they look, and the wording rarely shouts about it.

Two promises wearing one lanyard

When you buy replacement windows, you are usually getting two separate guarantees. One comes from the manufacturer and covers the product — the frames, the glass unit, the hinges, the handles. The other comes from the installer and covers the workmanship — how the window was measured, fitted, sealed and finished. They can have different lengths, different exclusions and different people standing behind them.

That matters because the company most likely to disappear is not necessarily the one making the frames. A national profile manufacturer may still be trading in a decade. The small local fitter who did a lovely tidy job may not be. If your guarantee is really just the fitter's personal promise, it is only as sturdy as their business. That is not a reason to avoid local installers — far from it — but it is a reason to ask what happens if they pack up.

“Insurance-backed” is not a badge you can eyeball

You will see the phrase insurance-backed guarantee used a lot. In plain English, it should mean the guarantee is supported by an insurance policy, so if the business that issued it goes bust, an insurer can step in. That is a meaningful layer of protection. But the phrase itself is not magic. A logo on a quote is not a policy.

Ask for the actual documents. Who is the underwriter? What exactly is covered? Is there an excess? How do you make a claim, and how long does it take? Does the policy cover parts and labour, or only the glass unit? A genuine insurance-backed guarantee should come with policy wording you can read before you pay a deposit, not a vague sentence after installation.

Also keep the distinction clear: a FENSA or CERTASS certificate is evidence that the work was notified and complies with building regulations. It is not a ten-year repair fund. Useful paperwork, yes. A guarantee, no.

The question that matters when you sell

Most people do not think about transferring a window guarantee until they put the house on the market. Then a buyer's solicitor asks for the guarantee, and you discover it is either missing, non-transferable, or transferable only if you pay an admin fee and fill in a form within 30 days of the sale. None of that is unusual, but it is much easier to sort at the buying stage than the selling stage.

Before you sign, ask three things: Can the guarantee be transferred to a new owner? Is there a fee? What do I need to keep to make that happen? Get the answer in writing, even if it is an email. If the guarantee is not transferable, that is not automatically a deal-breaker, but you should know. It may affect how a future buyer views the paperwork, and it may affect how you value the job.

The guarantee health check

A decent warranty conversation takes ten minutes. Ask these before the deposit leaves your account:

• Who is legally responsible for the product, and who is responsible for the fitting?
• Is the workmanship guarantee insurance-backed? If so, who underwrites it?
• What is excluded? Condensation inside the glass, accidental damage, poor maintenance, alterations and wear-and-tear are common carve-outs.
• Does the guarantee cover labour and call-out charges, or just replacement parts?
• What voids it? Missed servicing, unauthorised repairs, or changes made by someone else can all matter.
• If the installer stops trading, what is the claims route?
• Can I see the full guarantee terms before I pay?

If the salesperson gets shifty about any of that, treat it as information. A firm that genuinely backs its work should be able to hand over the wording without drama.

Keep the boring bits

Once the job is done, do not just file the certificate in the loft and forget it. Keep the original quote, the invoice, the guarantee certificate, the policy documents, the FENSA or CERTASS notification, and any photos of the installation. Register the guarantee if the manufacturer asks you to. If you move house, hand the whole lot to your solicitor. A guarantee with no paperwork is a guarantee with a problem.

A ten-year promise is a nice number on a brochure. What matters is whether it has a real name, a real policy and a real claims route behind it. Check that before the fitters arrive, and you will not be the person in year seven holding a useless piece of paper and a phone that rings out.