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Heritage & sustainability, a view on glass

The theory of making our built environment more sustainable threatens to be greenwashed.

Michel Trompert

Which path should we take to live and work more sustainably? Public opinion is convinced that this must be done by insulating our buildings and is guided by the standards imposed by policy. Nevertheless, engineers, architects and academics seem to come to a completely different conclusion. So much became clear, amongst others, at the study day on heritage and sustainability, which was recently organised in Ghent by the Steunpunt Duurzaam Wonen en Bouwen (Sustainable Living and Building Support Centre) (Province of East Flanders) in collaboration with the University of Antwerp. I shared my story too, based on my concern for the future and our heritage. For while the initial stance – reducing our carbon footprint – must remain our goal, the current measures cynically lead to the promotion of (too) far-reaching material and energy consumption. In addition, numerous other aspects are ignored, such as health, heritage value, the lifespan of the new materials, and even the real utility of insulation.


At the study day in Ghent, the following speakers, in addition to myself, shared their views:

Luc Eeckhout, Architect urban planner, visiting professor at KU Leuven and expert on climate design 

Guido Stegen, ARSIS bvba, Architect company and guest lecturer at Ghent University, the Free University of Brussels and Institut Chaillot. 

Birgit van Laar, Monumentenwacht Vlaanderen vzw (Monument Watch Flanders) 

Liesbeth Langouche, Dr. Conservation & restoration 

Nathan Van Den Bossche, Professor at Ghent University, Faculty of Engineering and Architecture 

Esther Geboes, Free University of Brussels, Architectural Engineering Lab 

Despite the diverse backgrounds and expertise of the speakers, there was a strong consensus on the need to revise current policies and even consider the existing heritage as part of the solution. I did this by putting the results of 5 decades of sustainable development into words and images. 


For example, I am saddened to see how sustainable development of built heritage, despite all practical experience and climate changes, is still strongly stimulated. One of the participants said that recently monuments in a number of cities (such as the UNESCO-protected inner city of Amsterdam) are exempted from the permit requirement to replace windowpanes with modern insulating glass. With the exception of historically valuable windowpanes. But, as was expressed that day, “who judges that?”

In this respect, sustainability is a form of permissible art destruction in slow motion.


As the climate heats up and less and less energy is needed for heating, the carbon footprint increases progressively, and more energy is consumed per inhabitant for the primary household. Nevertheless, insulation is still increasingly encouraged and only too gladly sold by businesses, based on assumptions and not based on science.

With the artificial models in which assumptions are made that are far removed from reality, we are moving towards a new illusory reality of sustainability. It is no longer about the climate or the right to healthy living and working, but about ‘what yields the most euros’. Your home, with insulation financed by grants, will now earn you more money, according to the broker. Although there is no theoretical evidence that this insulation is also effectively sustainable, the government believes that greenwashing is allowed. 


After a study by the Planbureau voor de Leefomgeving (Netherlands Environmental Assessment Agency) (PBL) that examined the climate contribution of sustainability measures, the government believes that the current sustainable development is the best direction to take and worth billions of euros of public money. 


My criticism of the PBL research (report Effects Draft Climate Agreement No 3619) is that the climate contribution is not only too low (35%), but also that the rising temperatures have not been taken into account which results less energy needed to heat buildings.

The LCA (life cycle analysis) has also not been taken into account, nor the degradation and actual life span of the so-called sustainability materials. The necessary maintenance of the technical materials is also not considered. The line of sustainability then becomes further and further removed from the necessary 1.5 ºC climate target.


The additional burden on health care is, in my opinion, part of the ever-increasing insulation pollution. It is highly likely that this pollution is associated with bacterial and fungal growth, particulate matter, volatile organic compounds, reduction of natural light and higher room temperatures as a result of insulated living and working spaces.  


The theoretical sustainability models are embedded in label, standard and subsidy systems to convert the difficult choices into easy earnings models. This means that there is no longer any critical reflection and only the own financial and short-term interest is met. 

The importance of an effective climate contribution does not seem to be a priority. The measures for which an energy label is obtained are not going to solve the harsh reality. At the same time, the assumption, in which it is presumed that insulating your home is part of the solution to fight climate change, is false reality.


The knowledge of the use of synthetic building materials has considerably improved in the past century. On the other hand, the application of a thousand years of experience and knowledge to use the proven natural and artisanal building materials has deteriorated catastrophically.


In the end, I come to the conclusion that there is a far-reaching tunnel vision that accepts the illusory reality only because it is already being applied in practice. There's no verification of the practices or any evidence. And I think that is urgently needed if we want to achieve the climate targets.


The 45 years I have worked at Van Ruysdael on regenerative systems and products, despite the opposition of the standards and labelling systems, strengthen me to continue to protect our living environment and our identity. 

On the one hand, by sharing 45 years of knowledge about windowpanes and protecting valuable and irreplaceable, and therefore sustainable, window glass.  On the other hand, by producing windowpanes on the basis of the artistic, useful and the most durable properties of authentic single glass, complying with the needs of this generation but without endangering the future generations here and elsewhere. 


6.5 mm Van Ruysdael glass is better than glass with the best insulation value as it reduces energy consumption more through minimal raw material use, a longer lifespan and optimization of thermal comfort. The thermostat can thus be lowered by a few degrees. Above all, this glass is also tailored to the context, which gives our built heritage better future value and performs better when it comes to beauty, acoustic comfort and a healthy living environment.  It eliminates the need for many compensatory measures. All these performances bundled in one product provides the necessary acceleration to reach the climate target.


In my opinion, we should not continue on the path that causes the climate problems, it motivates me to carry out further practical research into making the built environment more sustainable. Intended to continue to embrace our architecture and ultimately achieve more with less. 


And this is needed quickly and urgently!

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