Insurance-backed guarantees explained
When a window company promises a ten or fifteen-year guarantee, there is an obvious question few homeowners think to ask: what happens to that guarantee if the company itself disappears? A standard workmanship warranty is only a promise from the installer, and a promise is worthless if the business closes. An insurance-backed guarantee (IBG) exists to close that gap, and it is one of the most important protections to check before you sign.
What an insurance-backed guarantee actually does
An IBG is a separate insurance policy, provided by an independent underwriter, that stands behind your installer's own guarantee. If the company that fitted your windows ceases trading — through insolvency or simply shutting down — the IBG steps in to cover the terms of the original workmanship guarantee for its remaining period. In plain terms, it means a defect that appears three years after your fitter has gone can still be put right, rather than leaving you to pay again. The cover is tied to the guarantee, so it typically runs for the same length of time.
Why it matters more than people think
The window and home-improvement trade sees companies come and go, even long-established ones. Paying a premium for a “lifetime guarantee” means little if the firm behind it is gone within a few years. An IBG turns a paper promise into something enforceable, which is exactly why it forms part of the checklist for a genuinely vetted installer. It sits alongside accreditation as evidence that a company operates responsibly.
Want installers who back their work properly? Get matched with companies that offer insurance-backed guarantees.
Find UK companies →How to check yours is genuine
Ask three questions before you commit. First, is an IBG included as standard, or is it an optional extra you must request? Second, which underwriter provides it — you want a recognisable insurer, not an in-house scheme. Third, when will you receive the policy document? A legitimate IBG certificate is usually issued shortly after installation and names the insurer, the period of cover and what is included. Keep it with your FENSA or CERTASS certificate; both are documents a buyer's solicitor may ask for if you ever sell.
Where it fits with your other protections
An insurance-backed guarantee protects the workmanship after the job. It works best combined with deposit protection, which safeguards your money before the job, so you are covered at both ends of the transaction. Together they mean that neither an early collapse nor a defect years later leaves you out of pocket. Any reputable window firm will be comfortable talking through both, and a company that dodges the question has answered it for you.
A guarantee is only as good as its terms
Two guarantees of the same length can offer very different protection, so read the wording rather than the headline number. Check what the cover actually includes — sealed units, frames, hardware and the fitting itself may be treated differently — and note any conditions that could void it, such as skipping routine maintenance or using a third party for later adjustments. A guarantee that only covers the glass but not the installation, or that lapses the moment you have unrelated work done, is worth far less than it appears. Sensible questions here are also a quiet test of the company: a firm proud of its work explains the terms plainly, while one that waffles is telling you something. When you compare several installers, line the guarantees up alongside the prices — the cheapest quote with the weakest cover is rarely the best value once you look past the number on the front page.
Compare properly protected quotes — free and no-obligation, subject to eligibility and a home survey.
Find UK companies →