Profile Manufacturer, Window Fabricator and Installer: The 3 Roles You Need to Know

The three key players in a PVC window: manufacturer, fabricator and installer

When you buy a PVC window, three different companies are involved in the process, each with a specific role. Understanding who does what is essential for making a good purchasing decision, because the final quality of your window depends on all three — not just the profile brand.

These three roles are:

1. Profile manufacturer: designs and produces the PVC bars (KÖMMERLING, Veka, Rehau...).
2. Window fabricator: buys the bars and manufactures the window (cutting, welding, assembly).
3. Installer: fits the finished window in your home.

In this article we explain in detail what each one does, why quality matters at every stage and what questions you should ask before signing a quote.

The profile manufacturer: where it all begins

The profile manufacturer is the company that designs, formulates and extrudes the PVC bars that form the skeleton of the window. They are large multinationals such as KÖMMERLING (profine Group, Germany), Veka (Germany), Rehau (Germany), Deceuninck (Belgium) or Cortizo (Spain, aluminium and PVC). In Spain, the most common brands in the premium segment are KÖMMERLING and Veka, although Cortizo also has a significant presence, especially in aluminium with thermal break.

What exactly does the profile manufacturer do?

• Formulates the PVC: each manufacturer has its own formula. Stabilisers, impact modifiers and other additives are added to the base PVC to determine its resistance, durability and behaviour against sun and weather.
• Designs the system: defines the number of chambers, dimensions, seal types, compatibility with hardware and glazing. This is what distinguishes a 70 mm system with 5 chambers from a 76 mm system with 6 chambers.
• Extrudes the bars: the PVC is heated, plasticised and passed through an extruder that gives it the profile shape. It is cut into 6-metre bars.
• Carries out the foiling: in KÖMMERLING's case, foiling (including 3-sided Full Cover) is done in their own factories, not by the fabricator. This ensures direct quality control over the finish.
• Certifies: the manufacturer obtains the system certifications (Passivhaus, greenline®, air permeability and weathertightness classifications, etc.).

It is important to understand that the profile manufacturer does not make windows. It makes profile bars that are then sent to fabricators.

Why does the manufacturer matter?

The PVC formulation determines the long-term durability of the profile. Poorly formulated PVC can yellow, warp or degrade within a few years. Top-tier manufacturers such as KÖMMERLING, Veka, Cortizo or Ecoven Plus adapt their formulas to the climate of each region — for example, KÖMMERLING Spain has a specific formulation for the Mediterranean climate, different from its German factories.

Furthermore, the internal architecture of the profile (number of chambers, seal design, glazing compatibility) determines the maximum performance the window can achieve.

The fabricator: who builds your window

The fabricator (also called window manufacturer or PVC joinery) is the company that buys the profile bars from the manufacturer and transforms them into a finished window. This is probably the most critical link — and the least known — in the entire chain.

What exactly does the fabricator do?

• Cutting to size: cuts the PVC bars to the exact dimensions of each window, with 45° mitre cuts for the corners.
• Cutting reinforcements: cuts and inserts galvanised steel reinforcements inside the profiles to provide structural rigidity.
• Milling and drilling: creates the slots for drainage, hardware, handles and other components.
• Welding: joins the profile corners by thermal fusion. Weld quality is critical for the window's weathertightness and durability.
• Weld cleaning: removes welding flash to achieve a clean finish.
• Hardware fitting: installs hinges, espagnolette, locking points and tilt mechanism.
• Glazing: fits the glass (double or triple) with beading and weathertight seals.
• Quality control: verifies that the window opens, closes and seals correctly.

The big problem: variability between fabricators

This is where many customers get surprised. Two windows with the same profile brand can have completely different manufacturing quality if they are made by a different fabricator.

Why? Because in Spain there is no strict regulation governing the relationship between the profile manufacturer and the fabricator. Some manufacturers establish networks of "official fabricators" or "approved fabricators", but this recognition is usually based more on commercial criteria (purchase volume, exclusivity) than on thorough technical controls of manufacturing.

This means that:

• A fabricator may cut corners (literally) on weld cleaning.
• Steel reinforcements may be of lower quality or not properly secured.
• Hardware may be generic rather than that recommended by the profile manufacturer.
• Window adjustment may be poor, affecting weathertightness.

Our recommendation: before signing a quote, ask who the fabricator is, how many years they have been manufacturing, what volume they produce and whether you can visit their workshop. A professional fabricator will have no problem showing you their facilities.

The installer: the last link (and the most important)

The installer is the person who fits the finished window into the opening in your facade. Although it may seem like the simplest step, it actually has the greatest impact on the real-world performance of the window in your home.

What exactly does a good installer do?

• Pre-measurement of the opening: taking measurements with millimetre precision is essential. A measurement error means excessive gaps or, worse, a window that does not fit.
• Assessment of the substrate: analysing the condition of the wall, the existing sill, the roller shutter box and other elements that affect the installation.
• Installation planning: anticipating problems before they occur. An experienced installer knows that every opening is different and prepares solutions for potential deviations, plumb variations or irregularities.
• Removal of the old window: without damaging the wall or the interior finish.
• Preparation of the opening: levelling, cleaning and preparing the bearing surface.
• Fixing the window: using mechanical anchors to the wall, correctly spaced and tightened.
• Perimeter sealing: applying polyurethane foam and/or silicone sealant to ensure air and water tightness. This is one of the most critical phases.
• Hardware adjustment: verifying that all locking points exert the correct pressure on the seals.
• Final checks: testing opening, closing, weathertightness and tilt operation.

What no catalogue can give you: the experience of someone who has seen windows age

There is something that no technical data sheet, no sales brochure and no Google search can offer you: knowing how a window actually performs after 5, 10 or 15 years installed.

You can compare Uf values, read about chambers and seals, study air permeability tables. But when it comes to deciding, you face a question you cannot answer yourself: who fabricates the best windows with this profile?

You cannot know. And that is normal. Because the only real way to evaluate a fabricator is to work with their windows for years. To see whether the welds hold up. Whether the hardware maintains its adjustment after thousands of openings. Whether the glazing seal remains watertight when the storms of the fifth winter arrive. Whether the foiling keeps its colour after entire summers in the Mediterranean sun.

That information is not on the internet. The profile manufacturer does not have it. The salesperson selling you the window does not have it. The installer who has spent decades fitting, inspecting and watching how windows from dozens of different fabricators age has it.

That is why one of the most valuable functions of a specialist installer — and probably the least visible — is helping you choose the right fabricator and profile for your specific situation. Not the most expensive, nor the most advertised, but the one that best suits your home, your budget and the real conditions of your area.

At Instal Tancaments we have been installing windows in Girona and the Costa Brava for over 25 years. We have worked with virtually every fabricator and brand on the market. Some have pleasantly surprised us; from others we have learned that the name does not always guarantee the result. That accumulated experience is what allows us to make a rigorous selection and recommend, with real judgement, the combination of profile and fabricator that best fits your project.

Trust someone who has seen the long-term result. It is the only honest way to know what really works.

Why is the installer so important?

You can have the best profiles on the market — a KÖMMERLING Xtrem 76MD certified Passivhaus, a Veka Softline 82 with 7 chambers, a Cortizo A84 with thermal break or an Ecoven S82 high efficiency — made by the best fabricator, but if the installation is poor, the real performance of the window can drop dramatically:

• Poorly executed perimeter sealing allows air infiltration that nullifies the thermal insulation of the profile.
• Incorrect fixing can cause the window to go out of square over time, affecting closure.
• Inaccurate measurements force excessive gap filling, creating thermal bridges.

At Instal Tancaments we have been installing windows for over 25 years in Girona and the Costa Brava. Our experience has taught us that prior preparation and anticipation of problems is what makes the difference between a correct installation and an excellent one.

How to choose well: the questions you should ask

Before signing a window quote, we recommend asking your supplier these questions:

About the profile manufacturer

• What brand and model of profile is it? (e.g. KÖMMERLING Xtrem 76MD, Veka Softline 82, Cortizo A84)
• What certifications does the system have? (Passivhaus, technical classifications)
• Is the PVC formulation adapted to the Mediterranean climate?

About the fabricator

• Who manufactures the window? Where is the workshop located?
• How many years of experience do they have as a fabricator?
• Are they an official or approved fabricator for the profile brand?
• What hardware do they use? Is it the hardware recommended by the profile manufacturer?
• Can I visit the workshop?

About the installer

• Who will carry out the installation? Is it their own staff or subcontracted?
• How many years of experience does the installation team have?
• What perimeter sealing system do they use?
• Does the quote include removal of the old window and preparation of the opening?
• Do they offer a specific guarantee on the installation?

Frequently asked questions

Is the profile manufacturer the same as the window manufacturer?

No. The profile manufacturer (KÖMMERLING, Veka, Cortizo, etc.) produces the PVC or aluminium bars. The fabricator or window manufacturer buys those bars and transforms them into a complete window with glazing, hardware and seals. They are different companies.

Does the fabricator have to follow the profile manufacturer's instructions?

Profile manufacturers provide technical manuals and fabrication recommendations, but there is no regulation requiring the fabricator to follow them. This means that within the same brand you can find windows with very different manufacturing quality depending on who fabricated them.

Is it better if the fabricator and installer are the same company?

Not necessarily. What matters is that both are experienced professionals. However, when the installer knows the fabricator and they work together regularly, coordination is better and problems are resolved more quickly.

What happens if the window has a manufacturing defect?

If the defect is in the profile (discolouration, warping), the guarantee is covered by the profile manufacturer. If the defect is in the fabrication (poor welding, faulty hardware), the guarantee is covered by the fabricator. If the problem is with the installation (infiltration, misalignment), the guarantee is covered by the installer. That is why it is important to know who each one is.

Why do many companies present themselves as "manufacturers" when they are only installers?

It is a common confusion in the sector. Many companies that install windows call themselves "manufacturers" when they are actually installers who buy pre-fabricated windows. It is not necessarily bad, but it is worth knowing who actually manufactures the window so you can evaluate the fabrication quality.

What is an approved fabricator?

An approved fabricator is one that belongs to the official network of a profile manufacturer. In the case of KÖMMERLING, for example, they have the Official KÖMMERLING Network. Being approved implies a certain level of commitment to the brand, but the scope of quality controls varies by manufacturer.

Conclusion: the complete chain matters

Choosing windows is not just about choosing a profile brand. It is about choosing three links in a chain: the profile manufacturer, the fabricator and the installer. If any of the three fails, the end result suffers.

Our advice: investigate all three. Ask questions, compare and do not settle for just the profile brand name. A good profile in the hands of a poor fabricator or installer will not deliver the performance it promises.

At Instal Tancaments we control two of the three links: we are multi-brand installers — we work with KÖMMERLING, Veka, Cortizo and Ecoven Plus — and we do something that few can: select the best fabricators based on over 25 years of watching how their windows age, and carry out the installation with our own team. We do not delegate, we do not subcontract, we do not improvise. We recommend what we know works because we have verified it — not in a catalogue, but in hundreds of real homes over decades.

If you want to know more about our windows or need advice for your project, contact us with no obligation. We will explain exactly who manufactures, who fabricates and who installs your windows — and why we have chosen each one.

If you want to know more about our windows or need advice for your project, contact us with no obligation. We will explain exactly who manufactures, who fabricates and who installs your windows.