How Estimia Verifies the Companies on Its Platform

When you are about to spend €4,000, €10,000 or more replacing the windows in your home, the hardest part is not choosing aluminium over PVC or a tilt-and-turn over a slider. The hardest part is knowing who you can actually trust to do the work — and to still be around if something goes wrong two winters later.

That is the problem Estimia exists to solve. We do not manufacture or install anything ourselves. We are a marketplace that connects homeowners in Spain with installers, and our entire reason for being is that the companies you find here have already been checked. This article explains, step by step, how that checking works — so that when you see a company carrying the Estimia badge, you know exactly what it means.

Why verification matters in this market

The Spanish window and enclosure sector is huge, fragmented and largely unregulated at the point of sale. Anyone can print a business card, rent a small showroom and call themselves a carpintería de aluminio. Most are honest and competent. But a meaningful minority are not: they take large deposits and disappear, fit cheaper profiles than quoted, ignore the thermal-bridge detailing that the CTE (Código Técnico de la Edificación) actually requires, or vanish the moment a warranty claim appears.

Homeowners have almost no way to tell the two groups apart from a glossy quote. Reviews can be faked, photos can be borrowed, and a low price often hides exactly the problem you are trying to avoid. Verification is how we close that information gap on your behalf.

The verification steps

We apply the same checks to every company before it is allowed to appear in search results and receive enquiries. None of these are optional, and a company that fails any of them does not get listed.

1. Legal and fiscal checks

The first thing we confirm is that the business legally exists and is properly registered to do this work.

• CIF / NIF verification. We confirm the company’s tax identification number and that the trading name matches the registered entity. A company quoting under one name while invoicing from another is an immediate red flag.
• Activity registration (epígrafe IAE / CNAE). We check that the company is actually registered for window manufacturing, carpentry or installation work — not, for example, a general construction shell with no relevant activity declared.
• Standing with the authorities. We look for signs that the business is operational and trading legitimately, rather than dormant or recently dissolved.

This protects you in the most basic but most important way: it filters out the operators who cannot, or will not, invoice you legally — which is also what protects your right to claim IRPF deductions and NextGenerationEU grants later, because those require proper documentation from a registered installer.

2. Insurance and liability cover

Window installation involves heavy glass, working at height, masonry alterations and your home’s weather envelope. Things can and occasionally do go wrong.

We require listed companies to hold civil liability insurance (responsabilidad civil) appropriate to their activity. This means that if an installer damages your property, injures someone, or causes a leak that ruins a ceiling, there is a real policy behind the apology — not just a promise. We treat the absence of valid cover as disqualifying.

3. Real reviews and portfolio validation

This is where most directories stop being useful, because they simply republish whatever a company submits. We do the opposite.

• Reviews are checked for authenticity. We look for patterns that indicate genuine, independent customer feedback rather than a burst of five-star entries posted in a single week from suspiciously similar accounts.
• Portfolio validation. The project photos a company shows must be its own work. We verify that the portfolio is consistent — same workmanship, same standard, plausibly the same teams — and that it reflects the kind of jobs the company claims to do. A firm advertising large terrace enclosures should be able to show large terrace enclosures it has actually completed.

The result is that the gallery you browse on a company’s Estimia profile is a fair representation of what you will get, not a stock-photo fantasy.

4. Track record

A company’s history tells you a great deal that a quote never will. We assess how long the business has been trading, the volume and type of work it has delivered, and whether it has the practical experience for your specific project. Replacing two bedroom windows and glazing a 40 m² rooftop terrace are very different jobs; track record is how we judge whether a company is genuinely equipped for yours.

5. Quality criteria

Beyond legitimacy, we apply quality standards to the work itself. We expect listed companies to:

• work with recognised, traceable profile systems and properly CE-marked windows that carry a real Uw value and performance declaration;
• understand and respect the thermal-bridge and air-tightness detailing the CTE requires, rather than just dropping a frame into a hole;
• provide clear, itemised quotes that state the profile, the glazing, the U-value and the warranty — not a single vague total.

Companies that consistently meet these criteria are the ones that earn and keep their place on the platform.

Ongoing monitoring — verification is not a one-time stamp

A check that happens once and is never repeated is almost worthless, because companies change. Teams turn over, owners sell up, standards slip. So verification on Estimia is continuous, not a one-off badge issued at signup.

We monitor the signals that matter after a company is listed:

• New reviews and complaints. A rising pattern of unresolved problems — no-shows, abandoned jobs, ignored warranty claims — counts heavily against a company.
• Responsiveness. Companies that repeatedly ignore enquiries from homeowners are failing the one thing the platform exists to deliver.
• Continued legal and insurance standing. If a company’s registration or cover lapses, so does its eligibility.

Underperformers are removed. A company that stops meeting our standards loses its listing and can no longer receive enquiries through Estimia. This is the part homeowners rarely see, but it is what keeps the platform worth using: the directory gets better over time because the weakest members are continually filtered out.

What the Estimia badge actually means for you

When a company appears on Estimia and carries our verification, you can read it as a concrete set of guarantees:

It does not mean Estimia did the work — we are the referee, not a player. It means we have done the homework you would otherwise have to do yourself across a dozen companies, and that the firms reaching your inbox have already cleared the bar.

How to make the most of it

Verification removes the bad actors; comparison helps you find the best fit among the good ones. The smart way to use the platform is to request quotes from several verified companies at once and compare them side by side — profile system, glazing spec, Uw value, warranty and price — rather than chasing installers one phone call at a time. Because every option in front of you is already vetted, you can focus your attention on the differences that genuinely matter for your home.

In short

Trust is not a feeling we ask you to take on faith; it is the product of a process. Estimia checks the legal and fiscal basics, the insurance, the reviews, the portfolio, the track record and the quality of the work — and then keeps checking, removing the companies that stop measuring up. That is what stands behind every listing.

When you are ready, compare verified window and glazing companies on Estimia and request several quotes to weigh up side by side — with the reassurance that the vetting is already done.