You are at the fabricator's showroom. You have seen the samples, chosen the gorgeous anthracite colour and you are holding a quote that looks reasonable. The temptation to shake hands and leave a deposit is strong.
Hold on. Buying windows is a lifetime investment. A good salesperson can easily convince you, but a good craftsman only reveals himself when you ask the right technical questions. Here are 10 critical questions.
The first three questions target the core of the window - the materials that will determine its lifespan and energy performance.
Do not settle for "good Europa/Alumil". Ask for the exact series code. Confirm the profile is thermally broken (polyamide) and ask for the Uf value (frame thermal transmittance) - ideally below 2.0 W/m²·K.
Ask if the mechanisms are perimeter (locking top, bottom, sides) and request the brand (e.g. GU, Giesse, Siegenia, Roto). Avoid basic 1-2 point locks on balcony doors - they are vulnerable to break-ins.
Demand details: Is it energy-coated (Low-E)? Coating brand (e.g. Planitherm)? Does it have Argon gas in the cavity? What thickness (4-16-4 or 5-16-4)? A generic "double glazing" is no longer sufficient for energy compliance.
Installation is at least as important as the windows themselves. Ask how the sealing will be done and what the price includes.
The trap question! A proper professional will say they fill gaps with expanding polyurethane foam and seal with neutral silicone or MS Polymer - not basic acrylic mastic (which cracks in sunlight within 2-3 years).
Many fabricators remove the old windows and leave them on your pavement. Clarify that they will load, transport and recycle old frames without hidden charges.
Window replacement generates dust. An organised crew lays cardboard, covers furniture with plastic and vacuum-cleans on departure. Ask so you know what to expect.
The final questions address paperwork and after-sales - where the true professional shines.
Non-negotiable. If they say "you don't need those, I guarantee it", simply get up and leave. They are legally obliged to provide them under EN 14351-1.
Separate the factory warranty (for aluminium) from the fabricator warranty (hardware, silicone). Ask clearly: "If a roller breaks in 2 years or silicone leaks, do you come free of charge?"
Windows need adjustment. You want a professional who does not "vanish" after the sale, but answers the phone and comes for servicing 5 or 10 years later.
Request the delivery time in writing (e.g. 30 or 45 days). For payment, the industry standard is 40% deposit (material order) and 60% on completion and handover of the finished project.
A serious, certified fabricator will not be annoyed by these 10 questions - they will welcome them! They will see an informed customer who values quality.
If the fabricator gets irritated, dodges answers or tells you "don't worry about that", you know exactly what to do: move on to the next one. A professional who hides information before the order will rarely serve you well afterwards.
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