The Warranty Isn't the Wall: What Your Window and Door Guarantee Actually Promises

A ten-year guarantee on new windows or a front door feels reassuring. It suggests someone has your back for a decade. But when you actually read the paperwork, that generous headline often shrinks to something narrower: a product warranty here, a workmanship promise there, and a long list of things that are politely excluded. None of this means guarantees are worthless. It just means you need to know what you're relying on before you sign.

Two Guarantees in One Envelope

Most window and door guarantees are really two separate things bundled together. The first is product cover. That's the glass, frames, hardware and seals supplied by the manufacturer. This is often the part advertised as ten years, though even then it may be prorated or limited to certain components.

The second is installation workmanship. That covers how well the fitter sealed, levelled and finished the job. Workmanship cover is frequently shorter — sometimes just one or two years — unless the installer has paid for an insurance-backed guarantee that extends it. Homeowners often assume the ten-year figure applies to everything. It rarely does.

Ask your installer to spell out both in writing: what product cover you get, what workmanship cover you get, and how long each lasts. If they can't separate the two, that's a warning sign.

The Exclusions That Do the Heavy Lifting

Every guarantee has exclusions, and they're usually where the real story lives. Common ones include fair wear and tear — handles, hinges, locks and rubber seals are expected to degrade with use. Accidental damage, breakage and vandalism are almost always excluded. So is condensation inside the glass unit, unless it's a sealed-unit failure caused by a manufacturing defect.

Some guarantees also exclude problems caused by poor maintenance, incorrect cleaning products, building movement, or extreme weather. That last one can be broad. If a storm damages a window, you may find yourself claiming on home insurance rather than the guarantee.

The practical move is to ask for the full guarantee document before you pay a deposit. Read the exclusions section first, not last. If something isn't clear, ask the installer to highlight exactly which clause covers it. A vague verbal reassurance isn't the same as a written promise.

When the Installer Stops Trading

This is the big one. A guarantee is only as good as the company standing behind it. If your installer goes out of business, a standard workmanship guarantee from that firm is effectively worthless. You can't claim against a company that no longer exists.

That's where insurance-backed guarantees come in. These are policies from a third-party insurer that pay out if the installer can't honour the guarantee — usually because they've ceased trading. They're not automatic. You need to check whether your guarantee is actually insurance-backed, who the insurer is, and what the policy covers. Ask for the insurance certificate and the policy wording, not just a logo on a leaflet.

Competent-person schemes like FENSA and Certass are often mentioned in the same breath, but they do a different job. They confirm that the installer is registered and that the work should comply with Building Regulations. A FENSA certificate is not a ten-year workmanship warranty. Some schemes offer insurance-backed guarantees as part of membership or as an add-on, but you need to check the details rather than assume.

Transferring the Guarantee When You Sell

If you move house within the guarantee period, can the new owner rely on it? Often yes, but not always automatically. Many guarantees are transferable, but the process may require notifying the provider and paying an administration fee. Some require the transfer to happen within a set time after completion.

If transfer isn't done properly, the guarantee may lapse. That matters when you sell, because buyers and their solicitors increasingly ask for evidence of window and door guarantees. Keep the paperwork safe, and if you're selling, check the transfer process early rather than leaving it to the last minute.

The Questions to Ask Before You Sign

A good installer will welcome these. A poor one will dodge them.

• Is the guarantee insurance-backed? If so, who is the insurer and what is the policy number?
• What exactly is covered — product, workmanship, or both — and for how long?
• What are the main exclusions? Ask for them in writing.
• Is the guarantee transferable to a new owner, and what does that cost?
• What happens if your company stops trading?
• Are you registered with FENSA, Certass or another competent-person scheme?
• Can I see the full guarantee document before I pay a deposit?

It's also worth remembering that your statutory rights sit alongside any guarantee. The Consumer Rights Act 2015 says goods must be of satisfactory quality and services must be carried out with reasonable care and skill. A guarantee doesn't replace those rights, and it shouldn't be used to limit them unfairly.

The Bottom Line

A guarantee is a useful safety net, but it's not a wall. It won't stop a problem happening, and it won't cover everything if one does. Read the small print, ask about insurance backing, and check how workmanship cover differs from product cover. A few minutes with the paperwork now can save you a lot of frustration later — especially if the installer who promised you ten years is no longer around to answer the phone.