How did it all start at the time?
There were only a few who believed in and worked on energy-efficient buildings. In 1994 Heinz Übersax and Ruedi Kriesi created the concept of Minergie standards and built two Minergie houses in Kölliken, canton of Aargau. During 1988 to 1990, the house in Wädenswil, canton of Zurich, with zero-heating energy system provided them a solid foundation for the concept of Minergie. In 1991, the Swiss National Research Exhibition ‘Heureka’ was published, which presented a copy of the zero-heating energy system from Wädenswiler. It already had an airtight shell, and a comfortable ventilation system with heat recovery, demonstrating the better possibilities.
Afterwards, the canton of Zurich and the canton of Bern joined – marking another milestone. They acquired the Minergie brand in 1997 and founded the Minergie Association a year later.
The modern timber construction has made a significant contribution to the development of Minergie, thanks to the renewable building material and precise prefabrication, it is predestined for energy-efficient constructions. Besides, I believe that it wasn't just about «prefabricated houses», energy-efficient buildings should also be presented in appealing and contemporary architecture. By the way, that was also the reason why I founded the Architos Association, a nationwide network of professionals in all fields of wood architecture in Switzerland.
What’s the difference between the typical Minergie building owners in the past and at present?
In the past, we were pioneers in this field – only the «eco-freaks» believed that the environment was important. Today, Minergie has become an established standard for everyone. You should not build in any other way.
Which were Renggli’s most influential Minergie buildings?
I would choose three. The passive house at Wigger in Nebikon in 1999 was the first highlight of our energy-efficient buildings. It was certified by the Passive House Institute, led by Professor Dr. Wolfgang Feist. With the support from the European research project «Cerpheus», we built the first passive house in Switzerland, so called «zero-energy houses».
In the year 2000 we realised a solar house at the Federal Square in Bern within 24 hours. I bet with Gallus Cadonau, Managing Director at Solar Agentur Schweiz (Swiss Solar Agency, translated by editor) that we could do it – and we won the crazy bet.
In 2001, together with Lischer + Partner Architekten from Lucerne, we realized our second passive house (meeting Minergie-P-Standard) on behalf of the Lucerne Pension Fund: «Senti», 9 double-family houses in Kriens.
Minergie has certified over 46,100 buildings, which is your favorite and why?
Soon after the first-stage development, we wanted to build Minergie buildings in timber more than just two-storey single-family houses. It was not easy due to the fire protection regulations at the time. That's why I like our four-storey mixed-use (office and residential) building in Sursee – it promoted multi-storey timber constructions throughout Switzerland. Back then, we worked intensively with the building insurance company Lignum, Holzwirtschaft Schweiz and Reinhard Wiederkehr from Makiol Wiederkehr AG. These research results and experiences from realized construction projects have been incorporated into the standards of the Association of Cantonal Fire Insurers (Vereinigung Kantonaler Feuerversicherungen, VKF) regularly.
You have been on the Minergie board for years, what is your motivation?
I care about sustainability. We have the biggest leverage for energy conservation in building and mobility sectors, which together account for about 70% of the final energy consumption in Switzerland. That's why I'm especially interested in energy- and resource-efficient buildings, more importantly, with appealing and contemporary architecture!
What is your personal goal as a board member of Minergie?
It’s definitely energy conservation. We should better invest our «energy» in innovation, or in the renovation of the obsolete building stock in Switzerland, where we have great potential to save energy.
What would Switzerland look like today without Minergie?
Minergie has strongly influenced and strengthened the awareness of planners and contractors of energy efficiency in Swiss building sector. Thus, it played a pioneering role in setting the model of codes and regulations in energy sector in cantons in Switzerland (MuKen).
Without Minergie, perhaps there would be more nested buildings that would consume larger amount of energy. The electricity and heating bills for households would be significantly higher. At hot summer nights we would hear loud air conditioning systems everywhere... I am glad that the Minergie standard has shaped the Swiss building standard in a positive way.
Where do you see the strengths of Minergie?
Minergie has a high level of acceptance as a brand and is by far the most important energy label in Switzerland. The important thing is that it’s not only about energy efficiency, but also focusing on the comfort of the residents.
What weaknesses do you see in Minergie?
Because of many different buildings and building categories, one needs to understand many factsheets and frameworks in order to construction Minergie-certified buildings. This is why we make efforts to ensure that the Minergie standard remains understandable and the certification is possible to obtain with reasonable effort.
What would you change immediately if you could decide on your own?
I would only allow one standard for energy efficiency for a small country like Switzerland! This would allow us to reduce the wide range of labels to the only one that is supported by all organizations. For planners and implementers that would offer more certainty and security.
Where will Minergie go in the future?
2016 was a groundbreaking year: we reorganized the association, revised the existing standards with experts and developed two products for both construction and operation phases. Now it's all about ensuring the continuity. In my opinion, we must pay high attention to the quality of Minergie buildings.