Energy efficiency and barbaric marketing

Over the years, the construction industry has been moving in the direction of energy efficiency and environmental sustainability.

However in some cases, this change has happened only from a marketing point of view: with this article, we provide you with two interesting stories.

At the time of the first class I took on “ecological buildings”, in 2002, the situation of the construction industry was quite different than the one today. Back then, you’d have to fight even to install a simple hot water panel: the common opinion was that “it’s just not worth it”. Back then, PV panels were known in Italy only through photographs from Germany.

Today, the market has changed. Sustainability has become a common topic of conversation, as well as energy efficiency and Passive Houses.

With the 2020 Near Zero Energy Building goal, the EU has set the roadmap for the years to come, although we have mixed feelings about the way this goal is set.

This shift towards more efficient building is happening for both new building and renovations/energy retrofits. The topic of energy performance of a building is tightly bound to health and comfort. Too often you see a poorly designed and built structure ending up with a low quality thermal envelope, full of thermal bridges and air leakages. It has become common that a brand new building ends up having mold and condensation problems.


We recently received the brochures of two separate window manufactures, and we’d like to highlight some interesting features for you.

The first one is a large Austrian manufacturer, which we’re naming “Fritz Windows”. “Fritz” is one of the leading companies of the European market, producing PVC windows. Some of its models are even certified by the Passivhaus Institut. Whether of not PVC is a sustainable product, goes beyond the scope of this article.

The second company is an Italian medium-size manufacturer, that has been producing wooden frame windows for over fifty years: we’re naming it “Luigi Windows”.


To become a market leader, you have to be good at sales. On the very first page of the Austrian brochure, right next to the photo of the actual window, you see the following “infrared” image:

Isotherms of the PVC window

It’s not correct to call it “infrared”. This image is the result of a finite element analysis according to ISO 13788, that allows to calculate internal minimum temperatures in order to avoid the risk of mold and condensation.

From this one image, we can spot a couple of details that shake the credibility of “Fritz”.

In the first place, a 10°C isotherm (50°F) implies that the calculation assumes a value of 50% for the internal relative humidity. At the time we received the brochure, in Italy you were required to assume a value of 65% (with a higher risk of condensation). Furthermore, a -10°C outer temperature (14°F) is unrealistic even as a peak temperature for most of Italy. “Fritz” did not do his homework for the specific needs of the Italian market: he just did a simple copy+paste of the analysis done for Germany.

The second, incredible mistake contained in the very same image is the actual result of the analysis:

the window has condensation!

finestra-pvc condensation
Translation from Italian: “Exceptionally good thermal performance. An optimal distribution of the isothermes to completely eliminate the risk of condensation.”

Cherry on the cake: the selling pitch below the image: “Exceptionally good thermal performance. An optimal distribution of the isothermes to completely eliminate the risk of condensation.”

“Fritz Windows”, European market leader for PVC windows, makes a fool of himself.

Many questions come to mind: who did the calculation? Who inserted this image in the brochure? Did anyone with some technical background checked this at all?

How many windows were sold by showing off this image, as if it proved the superior quality of the window? How many unaware clients and unprepared professionals got fooled?

From a marketing point of view, it’s as if Ferrari used photos like the following one in its advertising:

If this was a Ferrari’s ad, would it still be your dreamcar?


As far as “Luigi Windows”, the situation is quite different.

Here’s the finite element analysis in “Luigi”’s brochure:

The isotherm diagram contained in Luigi’s brochure

It’s all quite clear. The image is not an ISO 13788 analysis at all:

the picture is a fake!

The image has no physical meaning what so ever: it’s a simple color gradient, created with Photoshop (or some other similar software). It does not describe the thermal quality of the window, neither good nor bad. However it carries an important message: it shows the ignorance that permeates the construction industry.

We actually called “Luigi Windows” on the phone, to ask for some explanation. We were able to talk directly to Mr “Luigi” himself, the owner of the company. Here’s the explanation in his actual words:

“The image we inserted in the brochure is a romantic diagram, to show that if you have 0°C on the outside, you have 20°C on the inside”.

Mr “Luigi”, with his fifty years of experience in the window manufacturing business, lies shamelessly. He has no clue on how his window works from a thermal point of view.

Are “Luigi”’s windows bad? On the contrary: they seem to be some very straightforward 92 mm solid wooden frame windows. Besides the thermal calculation, however, such an important component of the thermal envelope needs to be installed by a competent professional, to avoid thermal bridges and air infiltration. In case of windows, the service provided by the manufacturer and the installer is therefore very important.

Would you trust a company that shows no shame in lying on its brochure?


In his play “Life of Galileo”, Bertolt Brecht states:

“The goal of Science is not to open the gates to an unlimited Knowledge, but to build a barrier to unlimited Ignorance” (*)

Over the years, we’ve been using our blog as a research tool. We try to identify, understand and present a variety of topics around the construction industry in Europe and North America.

We believe that the best way to allow the market to grow is by providing quality information to the public. By building a more informed Demand, the Offer will be forced to follow.

Arnold Schwarzenegger in the role of Conan the Barbarian (I always wanted to use this image in one of our articles!)

To cheer up the mood, we close this article with the ridiculous image of former Governor of California, Arnold Schwarzenegger, in his role of Conan the Barbarian. It’s just a joke, a joke that unfortunately describes the work ethics of many professionals: designer, manufacturers, contractors. The construction industry is morphing, however the actual steps done forward are still too few.

Even the best manufacturers make mistakes: you should never trust a pretty brochure, because it most likely contains large errors. The best technical sheets come in black and white.

“Fritz Windows” just made a mistake: its windows remain of good quality.

“Luigi Windows” demonstrates the shabbiness of the industry. In order to sell, you don’t need your product to be good: you just need a “romantic” image.

(*) this is my personal translation from German to English.


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