Glazing Guarantees Explained

The three different guarantees behind a window installation, and what each one does not cover.

'Ten year guarantee' is one phrase covering at least three different things, held by different parties, covering different failures.

This guide separates them so you know what you actually hold after an installation — and what to ask for in writing before you buy.

The three types

Read every quote with these distinctions in mind:

Product guarantee — from the manufacturer, covering the frames, sealed units and sometimes hardware against defects.
Workmanship guarantee — from the installer, covering the fitting itself.
Insurance-backed guarantee — a policy that steps in if the installer ceases trading, offered through competent person schemes.

What guarantees usually exclude

Common exclusions worth checking:

Accidental damage and glass breakage.
Condensation on the room-side or outer surface of the glass, which is not a fault.
Failures caused by lack of basic maintenance, such as unlubricated hardware.
Movement or damage caused by the building rather than the window.
Colour variation on non-standard finishes, depending on the manufacturer's terms.

What to keep on file

Your itemised quote and contract, the competent person scheme certificate for the installation, any insurance-backed guarantee policy document, and the manufacturer's guarantee. A buyer's solicitor will ask for the certificate; you'll want the rest if anything fails.

Ask us what our guarantee covers

We'll give you the terms in writing before you commit, not after.

Frequently asked questions

Does a guarantee transfer if I sell the house?

It depends on the terms — some transfer to a new owner and some don't. Check the wording rather than assuming.

What's a Certass certificate?

Confirmation that the installation was carried out by a registered installer and notified as compliant with building regulations. It's the document conveyancers look for.

Is an insurance-backed guarantee automatic?

Not always — ask specifically whether one is included and request the policy document after installation.

All guides · Get a free quote