Pacific Interview: Building for Heat

Architect Somsak Traichai has spent two decades designing schools, clinics and housing blocks across Thailand and Laos without mechanical air conditioning, betting instead on airflow, shading and materials chosen for how they behave at 38 degrees rather than how they photograph. His firm's public housing project in Khon Kaen, completed last year, records interior temperatures roughly six degrees below ambient without a single compressor. Hannah Brooks spoke with him in his Bangkok studio, where the windows were open and the ceiling fans were, notably, off.

On why he stopped specifying air conditioning

Brooks: Most architects working in this climate treat air conditioning as a given. When did you stop?

Traichai: Around 2009, on a school project in Udon Thani. The budget for cooling was cut halfway through construction, and I had a choice: redesign around no mechanical cooling, or build a hot box. I chose to redesign, and the building performed better than anything I had done with air conditioning. That embarrassed me, honestly. I had been solving the wrong problem for fifteen years.

On what actually works

Brooks: What replaced the compressor?

Traichai: Cross-ventilation is the obvious one, but it only works if you design the section, not just the plan — the vertical relationship between floors matters more than most architects admit. We also went back to materials our grandparents used and industry abandoned: fired clay block instead of concrete block, because clay has thermal mass that concrete lacks at the same cost. And we stopped building deep floor plates. A building that is only one room deep can be cross-ventilated properly. A building three rooms deep cannot, no matter what you put on the roof.

"Air conditioning didn't fail us. It let us stop asking a harder, better question."

On resistance from clients

Brooks: Do clients push back?

Traichai: Constantly, at first. Developers assume no air conditioning signals a budget project, which is a marketing problem more than a design one. What changed my sales pitch was data, not argument — showing a client the actual electricity bill of a completed building next to a conventional one of the same size. A hospital wing we finished in Loei runs at roughly forty percent of the electricity cost of its older wing next door, same number of beds. Once a client sees that number, the conversation changes from aesthetics to arithmetic.

On whether this scales

Brooks: Can this approach work for a forty-storey tower in central Bangkok, not just a two-storey clinic?

Traichai: Honestly, only partially. Passive strategies lose effectiveness as buildings get taller and denser — you cannot cross-ventilate the fortieth floor the way you can the second, and land value in the city core punishes the deep setbacks and shading structures that make passive cooling work. My honest answer is that passive design solves perhaps sixty percent of the problem in a low-rise building and maybe twenty percent in a high-rise. The other eighty percent still needs mechanical cooling, ideally much more efficient than what we use now. I am not against air conditioning. I am against using it as a substitute for thinking about a building's shape.

On the region's building codes

Brooks: Should governments mandate any of this?

Traichai: Thailand's building code currently rewards insulation values borrowed almost wholesale from temperate-climate standards, which is close to useless here — insulating a wall to keep heat out works differently than insulating one to keep heat in. Vietnam and the Philippines are further ahead on climate-specific codes, in my view, mostly because typhoon exposure forced their engineers to think about building envelopes more rigorously decades ago. If our codes caught up with what field data already shows works, half of what I do as a specialist consultant would simply become standard practice. I would consider that a success, not a loss of business.