Climatic Architecture: Philippe Rahm's Wunderkammer of ideas
A conversation with Philippe Rahm on the fundamentals of his research and design methodology to tackle today’s climate crisis.

If the built environment is human defence from climate, it is also the activity with the most severe effect on the environment. Since the 1990s, Philippe Rahm has worked to develop an original understanding of architecture, its origins and its role, through an intense and multifarious set of activities. Rahm’s approach to the pedagogy and practice of the discipline would aim to reunite physics, chemistry, and physiology with architectural design, rather than retrofitting projects with prosthetic tools. Following the publication of his last book, Climatic Architecture (Actar, 2023), he looks back at his journey with Valerio Franzone.

KOOZ As we know, buildings are responsible for about 40% of global carbon emissions. In your work, you maintain that climatic phenomena can be design tools for architectural composition. How did your research start, and what sparked your interest in the relationship between climate, architecture, and physiology?

PHILIPPE RAHM The idea is that global warming is primarily a consequence of architecture, and it is easy to understand that architecture comes from climate problems. In their treaties, Alberti and Vitruvius explain the birth of architecture to defend the human body from adverse climates and keep its temperature at 37° Celsius. If the fundamental reason for architecture is to create a microclimate to survive, it's clear that the origin of architecture is climatic. But this also means the consequences are climatic and contribute to global warming. Many questions are coming from these assumptions: can architectural design be climatic? Why do we keep designing buildings using geometry or metaphors for composition and choosing materials instead of using climatic phenomena to design.

If the fundamental reason for architecture is to create a microclimate to survive, it's clear that the origin of architecture is climatic. But this also means the consequences are climatic and contribute to global warming.

For example, Mario Botta started with several houses based on the square, triangle and circle; Herzog and de Meuron started by designing buildings based on wood, stone and concrete bitumen — but it was in terms of geometry for the first one and language and cultural relation with the context the second one. Understanding the double relationship between architecture and climate, I started thinking about buildings based on climatic phenomena: designing houses based on convection, conduction, or evaporation, connecting the discipline of architecture to climate phenomena.

Physiological responses to excess heat, humidity, and pollution. Human beings must keep their core body temperature at 37°C, and to do so, they must evolve in an external air temperature of between 20°C and 28°C in which they will constantly cool the excess heat they produce.

KOOZ Trulli and vernacular architecture are examples of that...

PR Yes and many others in historical architecture. Palladio explains that the dome of La Rotonda serves to let the hot air escape; the portico protects from the sun; the windows and the doors are positioned to create an airflow to cool the building, and the plan is symmetrical to inhabit the villa according to the season. Before fossil energy, most of the buildings were based on climate issues, and this is why it's interesting to think about architecture climatically, because this principle is fundamental in architecture and because we are currently suffering from temperature rises.

When I was a student, I read Hegel, who said that architecture is a shallow art because it is subject to gravity, which affects the form of the building regardless of the architect's will. This is why he considers architecture not to be an intellectually-driven art. So I started reflecting on the materiality of architecture, realising that it is something we can't escape but must accept and work on. It is similar to what Arte Povera did, accepting concepts such as materiality and its natural transformation. These concepts, which are already ecological, were the basis of my first projects with Jean-Gilles Décosterd — with whom I had an office called Décosterd & Rahm associés. We tried to understand the chemicals inside concrete and how they interact with the environment. I started with this material, chemical, and ecological understanding of the building.

I then shifted my focus, from the solid elements of architecture to the void, questioning its materiality. Because what we represent as white on the paper is really composed of chemicals, electromagnetic wavelengths, humidity, toxins, and temperature. What looks like a void is, in reality, full of particles. For the Venice Biennale of Architecture in 2002, we presented the Hormonorium, a space where we didn't design the solid but the emptiness. We reduced the oxygen, added more nitrogen, and increased the light, understanding the influence of these changes on the hormonal system. The perception was no longer visual but hormonal, and the Hormonorium became like the Swiss Alps because the quantity of oxygen was the same at an altitude of 3,000 metres, and the light was like the one reflected by the glaciers. Then, I began connecting this chemical and spatial design of the void to the sustainability problem, because global warming demands that buildings first need to reduce energy consumption to manage the temperature and the air renewal, and it was all about the void.


KOOZ Bioclimatic architecture also considers local climate and is concerned with thermal comfort using environmental resources. Can you explain how your approach differs from it and how it eventually goes further?

PR When I did my first work, I was interested in the new techniques (thermal insulation, double flow air renewal, airtight membrane) to reduce CO2 emissions in the 1990s. However, bioclimatic architecture of the 1960s/1970s was forgotten at that time and absolutely absent of the corpus of references we have at that time; the general interest was more on Aldo Rossi then, and more generally on semiotics driven architecture. Then, it changed in the mid-nineties with programs like Minergie, concepts like passive housing, and consequent ideas to increase thermal insulation, to manage the energy loss in air renewal by using double flow systems with heat recuperation, and all these attendant technologies. My point was that these technologies, perceived as purely technical and delegated to engineers, are becoming so crucial in buildings that we have to consider them as architecture and, therefore, to design them: can the space we live in become a ventilation duct? Or can we live between two layers of thermal insulation? In 2006, we did a competition for the Tadeusz Kantor Museum in Poland, and it was based on the multi-glass technology for the windows, which form the boundary between interior and exterior. After each additional layer of glass, are we inside or outside? There are several interiors and exteriors, which is a graduation of interiority. So, we decided to expand the space between the layers of glass to insert the program and also to live in that space.

My approach was to revisit these somewhat nineties-era questions on ‘technique’ and to integrate these with architectural issues. My approach doesn't come from a bioclimatic approach, not even from the 1960s — because for a long time, we forgot that knowledge. When I was a student, we never heard about that research. Some of those ideas within bioclimatic architecture are linked to what I'm doing, but they have a different approach; the questions in the seventies came from the oil and resources depletion, while in the nineties they came from an awareness of global warming caused by CO2 emissions, so the answers are different. Nowadays, I have read recently a lot of anthropologists and philosophers like Marvin Harris or Alfred W. Crosby, from the 1970s. There is core research in anthropology and books published at that time that remains really interesting today. When there is an energy crisis, there is often a connection between various intellectuals and architects thinking about the same issues. Yet sometimes, they are not entirely informed of what people did before; for example, my generation comes from the postmodern period, a very superstructural period (language, culture, semiotics, metaphors, analogy), absolutely not interested in the material infrastructure (climate, energy, food, orography, epidemics) that remove from the discipline and for my generation all ability to think about material problems and to take seriously global warming in the architectural design.

KOOZ Postmodernism was a break from the previous multidisciplinarity.

PR Yes — maybe my early interest was not to be ecological per se but to challenge the architectural discipline to respond to that cultural environment. For example, Zaha Hadid or Frank Gehry later challenged the discipline with new computer technologies to conceive new forms. Similarly, I was challenging the discipline through thermal insulation and ventilation systems to find new ways of designing buildings against the new climate challenges. We must identify contemporaneity and understand that global warming completely transforms the discipline. We can challenge the discourse if we accept that and change how we think.

We must identify contemporaneity and understand that global warming completely transforms the discipline. We can challenge the discourse if we accept that and change how we think.

KOOZ You just mentioned a couple of architects with a strong formal approach, while on the other hand, you contribute to reintroducing the idea of the building as an ongoing process — which I find more revolutionary.

PR Previously, the indoor climate was considered unimportant, largely because fossil fuels were used to regulate indoor temperature. If the discourse is not about the infrastructure, it can only be about the superstructure: narrative, form, beauty or memory. But when you talk about revolution, it's because of the infrastructure. Maybe there is a background of fossil energy in the works of Rossi and Gehry. But fossil energy now shows its cons, changing the background. At that moment, floating in these changes of focus shifted the discourse from the superstructure to the infrastructure: now we understand that the most crucial element of architecture is the temperature inside of the building and how to regulate it without producing CO2. This challenge is revolutionising the approach to design.


KOOZ How do physiology and the different scales of climate meet in the design of the built environment?

PR If you think about climate, you must connect it with the human body and its temperature. When I started to do architecture, it was the beginning of computers and mobile phones; there was a discussion about electromagnetic radiation, blue light, and the consequent risks to our physiology and health. That’s how we started to become interested in these effects on the body.

Designing the space as a chemical quality is very important today, because our body is immersed inside it and not in front of an image of the Renaissance. For example, we once worked on a project for a park in Taiwan, which has a tropical climate. We had to find solutions for cooling outdoor areas. This issue, which at one time seemed exclusive to tropical cities, is now common in Switzerland or France during the summer’s heat waves where temperatures are always becoming warmer and warmer with the global warming. Regarding the indoors, I wrote a book called The Anthropocene Style about decoration — because carpets, tapestries, and curtains were initially conceived for thermal comfort in cold houses before central heating and their contemporary update. These things are connections between the body and the design of the space at different scales.

KOOZ Numerous publications have extensively surveyed the relationship between architecture and the climate. What books influenced your design research and projects and your editorial production?

PR My books are often a way to address things that I find to be missing. The first one, Physiological Architecture, presented the human body as swimming in space, affirming that we are not separated from architecture. It defined physiology in relation to architecture and marked the beginning of my climate research. Then, Natural History of Architecture presented a climatic approach to the history of architecture rather than a cultural or political one. It affirmed that humans are not the only designers; climate is also a designer. Climatic Architecture, my last book, is a summative presentation of all my work: how to understand the climatic phenomena and how the climatic phenomena design buildings. It intends to ground all these things. In this sense, my professional, pedagogical, research, and editorial work are all connected.

When I was a student — and also later — Aldo Rossi was really influential. I think of his treatise L'architettura della città and his Autobiografia scientifica, which have different approaches to architecture and are various formats of books. Autobiografia scientifica is a beautiful book because he's talking about himself, and it's an intellectual engagement. He is an influence in so far as his historical and autobiographical approach, but absolutely not in terms of his topics. Then there is Hegel, whom I took as a negative because he doesn't like architecture. So, I reverse what he says.

Jared Diamond's Guns, Germs, and Steel was vital because he was the first to bring back some material issues into the intellectual conversation; before this, things like climate, germs, diseases and so on were not mentioned in the historical narrative of 1980-1990, when I was a student. Then Peter Sloterdijk was one of the few who resonated with what I was doing. I also like Dipesh Chakrabarti today and feel utterly connected to his writings.

KOOZ I expected you to mention Banham’s The Architecture of the Well-tempered Environment or books like that.

PR When I started, we never heard about these books; they were sold out, and nobody was talking about them. A decade ago, an American student told me about Richard Neutra’s Survival Through Design, a book I had never heard of, but which also addresses comfort and climate issues. Now, we are rediscovering the ecology of the seventies and I refer to these titles, but when I was a student, they were mostly forgotten.

This book aims to show that in order to do a project, it is necessary to define a language and consequently, its vocabulary. Sometimes it is possible to use an existing language, but sometimes, a new one is necessary.


KOOZ You have published several books. The first one, Physiological Architecture, had a cover that glows in the dark — a manifesto on our physiologic relationship with space. The newest one, Climatic Architecture, is a Wunderkammer about your design research and merges different editorial formats. Can you explain its structure?

PR The material inside Climatic Architecture is not new in its totality, rather it emerges from projects and texts produced over the last 15 years. This book aims to show that in order to do a project, it is necessary to define a language and consequently, its vocabulary. Sometimes it is possible to use an existing language, but sometimes, a new one is necessary. I didn't want to simply discuss my projects; I wanted to talk about the tools and the material I use to develop my research: this is how we came to the idea of merging a dictionary, a handbook, an encyclopaedia, and a treaty, to reinvent a language and explore its origins. Physiological Architecture was based on a similar idea: from talking with scientists about physiology and its relation with the environment, and presenting the whole design process instead of just the final result. When one is a student, one does not have a lot of money; when buying books, they need something useful rather than egoistic books. That's why these two books largely attempt to provide information and ideas about climate and architecture.

Before publishing Climatic Architecture with Actar — and it was fantastic to work with them — I talked with Lars Müller and I must thank him for his input. He encouraged me not to make a traditional architecture monograph, showcasing my projects with a critic writing about me. He suggested that I approach it as the book of my life, working on everything, from graphic design to composing all the texts, and most importantly, to conceive a different kind of structure.

I wanted to talk about the tools and the material I use to develop my research: this is how we came to the idea of merging a dictionary, a handbook, an encyclopaedia, and a treaty, to reinvent a language and explore its origins.

The introduction is about climate and architecture in a general way. The first chapter, richly illustrated, discusses phenomena like convection, conduction, and evaporation, explained through physics and in architectural terms; it is a sort of encyclopaedia or dictionary, not exclusive to my projects alone. The second chapter is an autobiography that I originally published in France, called Météorologie des sentiments. This contains personal memories, like a version of Rossi’s Autobiografia scientifica. In the following chapter, I present our built projects. Then there is one chapter focussing on my research as exhibitions: exhibitions are a laboratory for me, a moment to focus on one issue and tackle it through an installation. Finally, I have compiled the texts of my projects; the result is like a compendium of writings explaining my philosophy. The resulting structure is half subjective or personal, and half objective.

KOOZ In this interview, as in your new book, you have combined subjectivity, like memories, and objectivity.

PR It's probably derived from the influence of Aldo Rossi. As I mentioned, L'architettura della città and Autobiografia scientifica represent two polarities, which I have appreciated since I was a student.

Climatic Architecture is a monograph but I want it to be generous; to open it to the readers, I have expanded its focus from myself towards the larger questions around climate. Subjectivity and objectivity are ways to look at both myself and the world.

KOOZ You mention Aldo Rossi often; was he relevant to developing your methodology?

PR Yes. Absolutely. Aldo Rossi was very clever; the continuity between his research through his different books and projects is incredible. It is something that taught me a lot. Today, my relationship with it is different; the content of his research is much less relevant — which doesn't mean it is not good, but today's material conditions require different approaches. If you keep defending ideas that are irrelevant to the contemporary urgencies of the environment and society, you are a reactionary. Rossi represents a method rather than content, to me.


KOOZ You tackle climate issues from a different perspective than the regular ‘Building Physics’ courses taught in architecture schools. I am interested in your approach to the overlap between research, professional practice, and pedagogy. How does Climatic Architecture constitute a pedagogical tool for today’s environmental problems?

PR Dipesh Chakrabarti, in his last book, states that previously, we maintained a distinction between human history and natural history. In the same way, when we talk about ‘Building Physics’, we imagine that this is separate from ‘Architectural Design’. We have an approach and a language for Architectural Design, but we consider Building Physics as something to understand mechanically — simplistically — because we know there will be an engineer on the job. This approach leads to a disconnection between these two disciplines, until we don't consider physics and chemistry as architectural design.

My friend David Gissen has discussed the same issue regarding design and disability, pointing out that accessibility should be considered as a starting point for architectural design. Thermal insulation may be the most crucial issue for architecture today — my idea is to consider Architectural Design and Building Physics as one thing and practise them together; otherwise, architecture is disconnected from climate issues. It means that we don't just have to be physically correct, we have to be critical with it — for example, by creating spaces between waterproof and thermal insulation layers. My pedagogy insists on these things.

It is crucial to understand today's research issues and then to allow the imagination to grow from there. That's both my fundamental pedagogy and my design method.

When I started teaching in 2005, I allowed my students to work freely on what they wanted regarding ecology and climatic issues, but I found the imagination and results to be poor, in the sense that they often mimicked popular images. I started setting specific topics — like thermal convection, for example — asking the students to study it scientifically; then, I told them to introduce a program, like a house, based on that phenomenon, which meant that the programme is not simply affected by this physical phenomenon, but is rather driven by it. That's an example of how I merge what is described as Building Physics and Architectural Design. What comes out is a process of invention, resulting in entirely new proposals and not prefabricated images. Doing this is very crucial to produce a built environment fighting global warming, and it permits architects not to be only designers making crazy forms but rather practitioners who have the responsibility and agency to act against climate crises and maybe making crazy forms from that.

This is what I mean about starting from the carbon footprint of the materials to changing design to allow for a revolution in architecture. It's like when Le Corbusier introduced the ‘Five Points’, which were the consequence of the introduction of reinforced concrete building technology; he understood reinforced concrete as the basis of form for a building. It is crucial to understand today's research issues and then to allow the imagination to grow from there. That's both my fundamental pedagogy and my design method, which I present in Climatic Architecture — which, in the end, is another pedagogical tool. The fact that it includes elements of an encyclopaedia, a handbook, personal memories and other editorial formats helps to create that.

KOOZ In my view, any educator should nourish students with both ideas and data, help them to build a method, and nurture their passion for the subject. Mixing methodology and sentiments always sparked my passions.

PR It's true and in a certain way, this is what Climatic Architecture aims to do: by providing technological tools and a scientific approach, but also showing my way of thinking, what affected me and led me to certain results, how and why I took certain decisions or had some ideas, my building sentiments and emotions, all resulting in my architectural approach.


Philippe Rahm is a Swiss architect and principal of the office “Philippe Rahm architectes” based in Paris. His work, which extends the field of architecture from the physiological to the meteorological, has received international recognition in the context of sustainability. His recent projects include the first prize for the 60 hectares Farini competition in Milan (2019), the 70 hectares Central Park in Taichung, Taiwan (completed in 2020), and a 2700 m2 architecture exhibition for the Luma Foundation in Arles, France. He has held professorships at Harvard University GSD, Cornell, and Princeton. He is the Dean’s Visiting Associate Professor at Columbia University GSAPP and a tenured associate professor at the National Superior School of Architecture in Versailles. (ENSA-V). In 2020, he curated the Natural History of Architecture exhibition at the Pavillon de l’Arsenal in Paris. Recently, he published his monograph, Climatic Architecture (Actar Publishers, 2023).

Valerio Franzone is the Managing Editor at KoozArch. He is a Ph.D. Architect (Università IUAV di Venezia), and his work focuses on the relationships between architecture, humanity, and nature. A founding partner of 2A+P and 2A+P Architettura, he later established Valerio Franzone Architect and OCHAP | Office for Cohabitation Processes. His projects have been awarded in various international competitions, and shown in several exhibitions as the 7th, 11th, and 14th International Architecture Exhibition - La Biennale di Venezia. His projects and texts appear in international magazines such as Domus, A10, Abitare, Volume, and AD Architectural Design.

26 Feb 2024
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