In Harare, Zimbabwe, there's a nine-storey office block and shopping centre called the Eastgate Centre that does something almost no large building does: it stays comfortable all year with no air conditioning at all. Its secret is that it was designed by copying termites.
Zimbabwe's climate is punishing — daily temperatures can swing from near freezing at night to the high 30s Celsius by afternoon. Yet local termites keep the fungus gardens inside their towering mounds at an almost constant temperature. They manage it with pure airflow: a network of tunnels and vents that draws cool air in at the base and lets hot air escape at the top, opened and adjusted as conditions change. No power, no machinery — just the shape of the mound and the physics of rising warm air.
When architect Mick Pearce, working with engineers at Arup, was asked to build an office block that wouldn't need Zimbabwe's expensive, power-hungry air conditioning, he looked at the mounds. The result, completed in 1996, works the same way. Cool night air is drawn in and stored in the building's heavy concrete floors. During the day, as people and computers warm the interior, that hot air rises and escapes through 48 brick chimneys on the roof. Low-power fans give it a nudge; that's the extent of the "machinery."
For comparison, the Eastgate Centre versus a conventional glass tower:
- Cooling energy used: up to 90% less
- Air conditioners: zero
- Chimneys venting hot air: 48
- Opened: 1996 — and still working
The payoff is huge. Using up to 90% less energy for cooling than a comparable air-conditioned building, in a country with an unreliable power grid, isn't just green — it's practical. Running costs are low, so rents are low.
There's a lovely twist in the science, too. Biologists once thought termite mounds worked like thermostats, holding a fixed temperature. Newer research suggests they behave more like a lung, breathing to exchange gases with the outside air. Either way, the principle the building borrowed — constant passive airflow instead of brute-force cooling — holds up beautifully.
The cleverest cooling system in Harare wasn't dreamed up by engineers. It was perfected by insects, over millions of years.