Philippe Rahm on using air, light, heat, and humidity as building materials

Swiss architect Philippe Rahm, who is about to give a public lecture in Melbourne, discusses the history and future of climatic architecture with architect and senior lecturer of architectural design Stuart Harrison.

Stuart Harrison: Philippe, thanks for joining me. What do you mean by this term, “climatic architecture?”

Phillipe Rahm: The basic idea of climatic architecture is to say that the origin of architecture is climatic. Why we are building is to create a microclimate where the human body can survive when it’s too cold outside or too hot outside. This is a primary reason of doing a building; this is the original reason of architecture.

And the consequence today is also climatic because we know that 39 percent of the CO2 emissions are from building. So, architecture is creating a climate change by heating, cooling, [and] using concrete and material – emitting a lot of CO2.

So now we are in between, like: cause is climatic, consequence is climatic. So, why we cannot choose climate for designing architecture, like tools for creating form, shape, function related to climate? So, this is what I name climatic architecture, to say that the tools can be climatic. So, instead of using perspective, for example, we are using convection; or instead of using metaphor, we are using evaporation; or instead of addition, when you are designing using a square or rectangle, maybe we can use thermal emissivity or thermal effusivity.

SH: It’s fascinating, Philippe. You talk about historical examples of architecture being climatically based. You cite the Villa Rotonda as a sort of climatic machine, saying that climate and energy efficiency are embedded in these types, but as a discipline, we’ve not learned these lessons maybe until now, until you’ve reminded us. Why do you think that is, that we haven’t been paying attention to the climatic properties of these historical precedents?

PR: I think it’s because fossil energy solved a lot of problem[s]. A radiator or airconditioning solved all the problem of climatic issue in the building. Vitruvius talked about solidity, commodity and beauty; and commodity was heating and cooling, but it was solved by systems. So, we don’t care anymore about commodity. And then for solidity, it was solved by concrete, reinforced concrete and steel. Reinforced concrete needs a lot of energy by burning the limestone to cement, and it emit[s] a lot of CO2, and by burning fossil energy for heating. [⁠…] And then there is only the beauty in this trinity of Vitruvius.

So, we talk only about beauty of a perfect square, or perfect circle, or perfect composition. It was just a discourse about form in a free way, without care about solidity and commodity. And so, for example, when I was a student, why did I never hear about convection in Palladio’s Villa Rotonda? I only heard about the perfect symmetry of the house. But in reality, Palladio is not doing that for the perfect symmetry; he places two rooms on the south for the winter and two rooms on the north for the summer to escape from the heat of the sun.

We completely forget, and we start to look, during the twentieth century, we look to architecture in a very strange way. But it was because we have the fossil energy supporting us. Now we have to come back to the infrastructure, the base level of energy and the climate, and to design with that instead of only designing with beauty.

SH: It’s fascinating that you’ve diagnosed this issue of just the abundance of energy as part of the problem, this disconnection between the Vitruvian poles. Modernity tried to standardise the indoor experience, make it around consistency rather than around variation. You talk about indoor weather and climate – do you think it’s possible for indoor experiences to vary more?

PR: I think the idea to have a constant perfect temperature indoor[s] is something that is very comfortable for a human body. We like it. We like airconditioning. We like central heating systems during the winter. Before that, it was quite difficult to survive for the people.

We know that during the Middle Ages, the temperature indoor[s] was very often 12 ℃ and not 20 ℃. So, it was very cold, and sometime it was freezing inside; we were gathering all together to share or eat. So, it was a different social way of living. But now, because we know that we can no [longer] use so much CO2, we have to think differently. And, maybe we can challenge the temperature inside. We can maybe say that, okay, it can be a subject of design to say we will not leave that to the climatic engineer, but as an architect, we will do our job also for creating the space as a materiality.

SH: So, that diversity is both a climactic diversity and an experiential diversity, a material diversity. And I think the way you often frame that is, [it] exists between two poles: sometimes vertically, sometimes horizontally. And is that a way of achieving that variation as well as creating an overall building system?

PR: Yes, very often there are two poles. It came from a Swiss recommendation to economise energy. It said the bedroom can be heated during the winter at 16 ℃ because you are inside the blanket, and the bathroom should be heated at 22 ℃ because you are humid and naked. So, you have a diversity of temperature depending [on] your physical activity and your clothes.

So, instead of [saying] to the climatic engineer, “Okay, do this room at 16 ℃ and do this one at 22 ℃,” why [not] place two radiators that will give a different amount of energy? So, one will be [⁠…] more like 15 ℃, and the other will be at 22 ℃. And then, in between these two, it creates different places in the space, in the atmosphere, with a variation of temperature. And we can say, “Okay, here, it will be good for the living room because it’ll be 20 ℃. Here, it will be good for the kitchen.”And this type of idea to stretch the project in between two poles, I use that as an urban design tool. For example, if you go outside during the winter, you are looking for the sun, and no wind, and heat. And if you are going in the public space during the summer, you are looking for shadow, for a lot of wind. So, you have different qualit[ies] of public space that will fit for the winter and for the summer [⁠…]. Why we cannot arrange the city also like that? To say, “Okay, this is a winter plaza; this is a summer plaza.”

SH: I’m really interested in ⁠– when doing particularly a building project in this way, it crosses from what we normally regard architects doing into what mechanical engineers do, which I think is good. Do you ever get pushback – resistance from engineers who start saying, “Hang on, this is my job”?

PR: Not really. In reality, I have most of the time very good relationship[s] with climatic engineers [⁠…] I think they like to work with me, even, because I understand what they are doing.
Very often, I receive a new idea from them [and] apply this new idea to the next project because I learn also by talking with them. [⁠…] I think the relationship is quite good with them.

SH: I’m also interested to know whether most of the projects you’ve worked on have been new buildings, or [have they] also been reusing existing buildings?

PR: Just now, we have just finished a competition for an old building. It’s interesting because we are keeping the structure, the static structure, load-bearing structure; and we are also using some part of the building; and then we are introducing inside thermal insulation and [a] new system of ventilation. So, I like both.

I think what’s happened in the last maybe 10 years, before the climate problem, the CO2 emission was more on the consumption of energy for heating and cooling and less on the construction itself. It was like three-quarters was about that, and one-quarter was about [the] carbon footprint of the material.

But now, because [of] the work on the thermal insulation and the better management of the heating and cooling system [⁠…] Now we understand in Europe – for example, in Switzerland or in Austria, because there [are] some studies about that – they show that now the carbon footprint of the material is half of the problem.

The first project I made on an existing building was a very old, old castle in Paris. And for that, we [kept] everything but introduc[ed] thermal insulation like a tapestry, or a carpet.

[That]’s the origin of my book called The Anthropocene Style. It’s a free book. And it was the idea to do some transformation of the interior in a decorative way by rethinking about decoration as it was before the fossil energy, as tools for warming the space: like a carpet was a thermal insulation, or tapestry was a thermal insulation, or [a] mirror was a way of reinforcing the light of the candle.

SH: So, the principles of a climatic architecture can be applied to existing buildings?

PR: Yes, yes, absolutely. With this idea of decoration as climatic tools, I think it’s a new way of rethinking decoration [as] a practical way [to improve] performance.

SH: I wanted to touch on this issue of what a climatic architecture looks like and feels like – how should it?

PR: I think, about the question of beauty or what the climatic will look like … I was at one moment thinking, “Okay, should we still use photography for that type of building? Should we not use thermography, like infrared photography to see the final result, to change also the grid of evaluation at the end?” Okay, take a thermal camera. And so, we can imagine a magazine that will show only thermal image.

SH: That’d be pretty cool. Thanks so much for talking with me today, and I’m looking forward greatly to your talk here in Melbourne.

Philippe Rahm will present a public lecture at the Melbourne School of Design on 27 August. To find out more, visit here.