Buying windows and doors from a local supplier makes sense. Someone can visit the house, measure the openings themselves, and come back if a hinge starts to drop three years later. But "local" is not a quality mark. Two firms a street apart can sell the same profile system with very different warranties, different fitters and different ideas about what a lead time means. The difference usually shows up in the answers to a handful of specific questions — the kind that are easy to ask before you sign and awkward to ask afterwards.

Who Actually Makes the Windows You're Buying?

Start with the direct question: do you fabricate the frames yourselves, or do you buy finished windows from someone else? Neither answer is wrong. A fabricator controls the build; a reseller may offer a wider choice and better installation. What matters is knowing which one you're dealing with, because it tells you who is responsible when something goes wrong.

Then go deeper. Ask which profile system is used — the brand and series of the extruded frame — along with the hardware (locking gear, hinges, handles), the glazing supplier and the spacer bar inside the sealed unit. Ask to see those names on the physical sample in the showroom: profile names are usually printed along the frame, and glass spacers often carry a manufacturer's mark.

Why bother? In ten years, replacement hinges and handles come from the hardware maker, not the showroom. A window built on a profile system that is widely distributed in your region is easier to service than one built on an imported one-off. Ask, too, where the sealed glass units are assembled. Local assembly means a faster replacement if a unit ever mists up.

Warranty: Read the Clauses, Not the Headline

Every supplier will tell you their windows are guaranteed. Few volunteer the shape of that guarantee. Ask for the warranty document itself, before you sign, and read it at home rather than in the showroom.

Specific things to pin down:

• What is covered. Frame profile, sealed glass unit against misting, hardware, handles, hinges, and the paint or foil finish.
• Whether labour is included or only parts. A free hinge that arrives with a callout charge is not much of a guarantee.
• How long each element lasts. Glass units, hardware and surface finishes are often treated differently from the frame itself.
• What voids it. Poor ventilation in a room, painting or altering the frame, fitting by a third party, coastal exposure — the list is often longer than buyers expect.
• Who honours it. The fabricator, the installer, or both? And what happens if the supplier stops trading?
• Whether it transfers to a new owner if you sell the house.

A guarantee you haven't read is a promise, not a contract.

Lead Times, Delays and Who Calls Whom

Get the lead time in writing, and make sure it has a clear starting point and end point: from the technical survey to installation, or from order confirmation to delivery? Those two answers can differ by weeks.

Ask what the typical current lead time is, not the fastest they have ever achieved. Ask what happens when it slips — because with made-to-measure products, it sometimes does. The useful question is whether anyone tells you before the day, and whether installation is booked by the same person who sold you the windows or by a separate scheduling office you've never spoken to.

There is a seasonal element worth raising. Orders placed in late spring, and orders placed just before the year-end break, tend to sit in longer queues. If your installation is tied to other work — a plasterer, a kitchen delivery, a flooring job — say so at the quote stage and ask the supplier to confirm the sequence in writing.

Who Is Coming to Fit Them?

Ask whether the fitting team is employed by the company or subcontracted, and whether the person who surveys your home is the person who hands over the finished job. Consistency matters more than job titles: a team that has fitted the same profile system for years will solve problems on site instead of promising to come back.

Ask what is included around the window, in detail: removal and disposal of the old units, making good inside and out, new internal trims, silicone and external sealing, and any sill or shutter work. Vague answers here turn into extra invoices later.

If you live in a flat, a listed building or a property with particular façade rules, raise it at the first visit. Ask whether the supplier handles any paperwork and what they need from you. Permission requirements and condominium rules vary widely, so check with your building administrator and, where relevant, a qualified professional before you order.

Performance Documents and the Numbers Behind the Pitch

Ask for the declaration of performance and test documentation for the window you are actually buying at the size and glazing specification you have chosen — not for the brochure system or a smaller test sample. Thermal transmittance, acoustic performance, watertightness, wind load and security ratings should all be traceable to the complete assembly.

If you intend to claim a tax deduction or incentive for the work, ask which documents the supplier provides and when they will be issued. Confirm eligibility with a qualified adviser; the rules change, and interpreting them is not the showroom's job.

Quotes, Payment and Variations

Ask for a fully itemised quote: each window by reference and size, glazing specification, hardware, finish, any integral blinds, delivery, installation, disposal, and VAT shown separately. A single total price hides the things you may want to change later.

Ask how variations are priced, and get that answer in writing too — for example, what happens if the survey reveals an opening that is out of square and needs extra work. On payment, request the schedule in writing and match it to milestones. A deposit is normal for a made-to-measure product; a large upfront sum deserves a contract that sets out what happens if dates slip or the order changes. For anything substantial, it is sensible to have the terms checked by someone qualified before you sign.

Turn the Answers Into a Scorecard

Ask the same questions of three suppliers and write the answers in columns. It takes an afternoon and it makes the decision far clearer than any showroom visit.

1. Who fabricates the frames, and which profile, hardware and glazing brands are used?
2. What exactly does the warranty cover, what voids it, and who honours it?
3. What is the written lead time, counted from which date, and what happens if it slips?
4. Are the fitters employed or subcontracted, and does the surveyor stay involved?
5. What making good, disposal, trims and sealing are included?
6. Which performance documents come with the finished windows?
7. What is the full itemised price, with VAT shown separately?
8. What is the payment schedule, and how are variations priced?

Then do two small things before deciding. Visit the showroom and operate a sample window yourself — open it, lock it, feel the weight of the handle. And ask to see a window from a recent local installation, or to speak to a customer whose job was completed a year or two ago.

A supplier who answers plainly, hands over the paperwork without being pushed, and puts both the lead time and the warranty into the quote is showing you how they will behave when a hinge fails in year six. That is the local advantage actually worth paying for.

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