Make or buy windows and doors: an analysis for resellers

If you run a windows and doors reseller business, or you’re a window fitter thinking about expanding, sooner or later you’ll ask yourself the question: does it make sense to set up your own production line, or is it better to keep buying finished windows from a manufacturer?

The answer depends on figures that are rarely put on the table honestly. This article puts them there.

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The real costs of a production line

Let’s start with what “opening a production line” actually means in practice. It’s not just about buying a cutting saw and a welder. A working line for PVC windows requires:

Machinery

The minimum equipment for a PVC line includes:

• Double-head cutting centre (mitre and 45°)
• Four-point welding machine
• Automatic weld-bead cleaning machine
• Milling machine for drainage slots and hardware seats
• Equipment for fitting glass and hardware

A set of used machinery in good condition starts at €60,000–90,000. New, with brands such as Rotox, Sturtz or Graf, you easily reach €150,000–250,000 for the basic line alone. Add a CNC machining centre for the jambs and you go over €300,000.

Note: annual maintenance of a line (tooling, lubrication, servicing) is worth 5–8% of the initial investment, every year.

Premises and infrastructure

An operational PVC line needs at least 300–500 m² of covered space, with a clear height of 4–5 m to move large frames around. Add a warehouse for the profiles (stored as 6 m bars), a quality control area and a packing zone.

Renting industrial premises in Northern Italy: €4–8/m²/month. Over 400 m² covered: roughly €20,000–38,000 a year in rent alone. Buying the premises: a building of that size in a logistically sensible location typically costs €250,000–600,000.

Staff

A line producing 20–30 units a day needs at least 3–4 skilled operators:

• 1–2 cutting and welding operators
• 1 glazing and hardware operator
• 1 quality control and loading/unloading supervisor

Gross labour cost in Italy (2026): €35,000–50,000/year per skilled window and door operative, including contributions. With 4 people: €140,000–200,000 a year in labour alone.

CE certification and production control

This is where a cost that’s often underestimated is hiding.

Windows and doors sold in the EU fall under the Construction Products Regulation (CPR 305/2011) and EN 14351-1. CE marking is a legal obligation and can’t be improvised.

To obtain it you need:

1. Initial Type Testing (ITT) — laboratory tests on samples of your window: air permeability, water tightness, wind resistance, thermal insulation (Uw). Every profile/glazing/hardware combination is technically a different type. The tests are carried out by notified laboratories and cost, for a complete set, roughly €10,000–30,000 per type.
2. Factory Production Control (FPC) — a documented, auditable system for controlling production in the factory. It requires written procedures, records and calibrated measuring instruments. A specialist consultant to set up FPC from scratch will cost you €5,000–15,000 plus recurring audits.

There’s a cascading ITT mechanism: when you use a profile system documented by the manufacturer (such as Salamander), you can rely on their existing ITT results, provided you stay within the tested configurations. This reduces testing costs, but doesn’t remove the obligation for FPC. And it ties you to exactly the combinations covered by the system house’s DoPs (Declarations of Performance).

In summary: CE marking for an in-house line requires an initial investment of €15,000–50,000 and an estimated annual maintenance cost of €5,000–10,000, with periodic reviews of the FPC system.

Material stock

An operational line can’t work hand-to-mouth. Profile stock (6 m bars in various sections), glazing, hardware, seals, packaging: a working inventory typically represents €30,000–80,000 of tied-up capital for a small line. That money earns you nothing and has to sit there.

The total bill: order of magnitude

Item	Indicative range (one-off)	Recurring annual range
Machinery	€80,000–300,000	€5,000–20,000 (maintenance)
Premises (rent)	—	€20,000–40,000
Staff (4 people)	—	€140,000–200,000
CE certification + FPC	€15,000–50,000	€5,000–10,000
Warehouse stock	€30,000–80,000	variable
Estimated total, year 1	€225,000–630,000	€170,000–270,000/year

These are orders of magnitude. The real figure depends on your geographic area, volumes, product types and specific organisational choices. None of these figures is a guarantee.

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The costs of “buying” from a manufacturer

Buying finished windows and doors from an external manufacturer means structuring your business in a completely different way. The figures take on a different nature.

The purchase price already includes workmanship, certification, the manufacturer’s labour and logistics. You don’t pay for machinery, you don’t hire operators, you don’t manage an FPC.

The margin is the difference between your selling price and the purchase price. With a manufacturer-supplier working at volume, the reseller margin typically ranges between 15% and 35% depending on the product segment, the contracted volume and the agreed terms.

Time to market is the manufacturer’s: if they have the production capacity and raw materials, lead times for standard windows and doors are in the order of days or weeks, not months.

Tied-up capital: close to zero in machinery. Your capital works in advertising, sales, showroom, after-sales service — all activities that generate margin instead of depreciating.

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Break-even on volume: when producing becomes worthwhile

The break-even logic is simple: you only produce in-house when the saving on industrial cost (the difference between making and buying) covers all the fixed costs of your line.

Let’s try some rough figures. Assume:

• Average purchase cost of a finished window from an external manufacturer: €200/unit (standard type, PVC, average size)
• Variable in-house production cost (profile + glass + hardware + direct labour): €110–130/unit
• Saving per unit produced in-house: €70–90
• Annual fixed costs of your line (staff + premises + maintenance + FPC): €200,000/year (low-end scenario)

Break-even: 200,000 / 80 = 2,500 units/year, roughly 210 units/month.

With higher fixed costs (owned premises, more staff, a better-equipped line) the break-even easily rises to 4,000–5,000 units/year.

For context, as an order of magnitude (an indicative estimate, not an official industry figure): an average independent reseller in Italy sells a few hundred windows and doors a year — say between 200 and 800 — while a mid-sized window and door installation business rarely exceeds 1,500. The break-even point for in-house production is realistically within reach of very few SMEs in the sector.

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Contract manufacturing as a third way

Between “I make everything myself” and “I buy everything ready-made” there’s a structured third option: relying on an external manufacturer who produces under your brand to your specification, without you building anything.

This model — known as contract manufacturing or private label — has specific features:

• The product goes to market under your brand, with no reference to the physical manufacturer.
• You define the specification, finishes and requirements: profile, RAL colour, hardware, glazing, tolerances.
• CE certification belongs to the manufacturer: you don’t have to build or maintain an FPC of your own.
• Zero industrial investment: your capital goes into sales, marketing, service.
• Real scalability: you can grow in volume without touching a production structure.

The honest downside: you depend on your supplier’s production capacity and quality. If the supplier has problems, so do you. Choosing the production partner is the single most important strategic decision in this model.

For anyone wanting to understand how the contract manufacturing model works in practice, the dedicated page covers the ground: contract manufacturing and private label production.

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When it’s worth it / when it isn’t

In-house production is worth it when:

• Volumes are high and stable: you consistently produce more than 3,000–5,000 units a year (not just peaks).
• You already have production infrastructure: existing premises, skilled staff, experience running an industrial operation.
• Strategic vertical integration: you’re a large construction firm with continuous sites that justify an in-house windows and doors department.
• Highly specific product niches that no standard manufacturer covers: unusual architectural geometries, workmanship outside standard systems.

It’s not worth it (for most):

• You’re a reseller with fewer than 1,000–1,500 units a year: you don’t reach break-even. Capital tied up in machinery returns less than the margin you could build as a well-structured reseller.
• You don’t have in-house industrial expertise: running a CE-certified line isn’t the same as managing a team of installers.
• You want to grow quickly: a production line takes 12–24 months to become operational, certified and up to speed. A contract manufacturing supplier can serve you within weeks.
• Your market is volatile: with fluctuating volumes, the fixed costs of production become a fixed burden on variable margins.
• You’re a window fitter focused on installation: your expertise is on site, not in industry. Diluting it is a risk, not an opportunity.

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How the choice changes depending on the profile system

A factor often overlooked: if you decide to produce in-house using a quality profile system (Salamander, Rehau, Aluplast), you’re still bound to the system house’s ITTs and DoPs. You use their tests, but you must stay within their tested configurations.

If you choose a generic profile without adequate ITT support, you have to carry out the laboratory tests yourself — and this pushes the initial costs back up.

Understanding the differences between profile systems (chambers, Uf, glazing rebate, tested configurations) is a separate subject: there’s a detailed technical comparison of Salamander profiles in the GreenEvolution vs BlueEvolution guide.

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FAQ

Is it worth a window fitter with 10 employees producing in-house?

Rarely. With 10 employees, installation volume is unlikely to exceed 1,000–1,500 units a year. At that volume, the fixed costs of a production line don’t pay for themselves. It’s better to position yourself as a strong buyer from a reliable manufacturer, negotiate volume terms, and keep your people focused on site work.

Does contract manufacturing mean losing control over quality?

No, not if you choose the supplier carefully. You need to check they use CE-certified systems, that they follow the agreed specification, and that they allow audits or sample checks. Quality is a contractual clause, not an automatic consequence of producing in-house.

How realistic is it to build a line from scratch in 6 months?

Not very. Finding premises, buying and installing the machinery, training staff, setting up the FPC system and obtaining the DoPs realistically takes 12–18 months in the best case. And during that period you produce little or nothing, while fixed costs are already running.

Does private label expose me to additional liability?

Yes, and it’s a point not to be underestimated. Under Regulation (EU) 305/2011 (CPR, Article 15), anyone placing a construction product on the market under their own name or brand is considered a manufacturer for all intents and purposes — with the related obligations (DoP, CE marking, liability), even if they didn’t physically produce it. So selling under your own brand doesn’t automatically make you a simple reseller: the division of responsibilities needs to be set out with a precise contractual structure, defined with a legal consultant. This article isn’t legal advice.

Is buying from a manufacturer with their own plant the same as buying from an intermediary?

No. An intermediary buys from third parties and resells: their margin is your additional cost, and they have no control over lead times or production specifications. A manufacturer with their own plant has the line under direct control, can produce bespoke without intermediaries, and the price reflects real industrial costs. It’s a structural difference, not a commercial one.

Are Salamander profiles binding if I choose an external manufacturer?

No, but the manufacturer’s choice of profile system affects certified performance and DoP availability. Salamander (with existing, documented ITTs) reduces certification complexity compared with less-documented systems. For anyone buying finished windows and doors, it’s a variable worth putting in the specification.

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Conclusion

For the vast majority of window fitters, resellers and small Italian construction firms, building an in-house production line isn’t a rational industrial choice. Fixed costs (machinery, staff, premises, CE certification) require break-even volumes that few SMEs in the sector reach consistently.

The model that works for those who make a living from windows and doors without industrial ambitions is choosing the manufacturer well: one with their own plant, certified systems, reliable management, able to produce bespoke and under your own brand if needed.

For anyone wanting to understand how wholesale supply works — manufacturer prices, no intermediaries — the starting point is our page on wholesale supply for resellers. For those wanting the product under their own brand with no industrial investment, the right ground is production and B2B supply.