In 1996, architects in Harare built a shopping mall modeled on termite mounds; its passive chimney vents kept the interior cool using 90% less energy

Long before “green building” became common language, a shopping and office complex in Harare, Zimbabwe, was showing how to stay cool without air conditioning. The Eastgate Center in Harare, opened in 1996, is described by Arup, the structural engineering firm that helped design it, as Zimbabwe's biggest office and shopping complex, which uses about 90% less energy to heat and cool itself than a conventional building. The explanation for that number lies underground, in the mounds built by termites.

A mall without air conditioning

Zimbabwe's national power grid has been under strain for years, and running heavy air conditioning around the clock puts even more pressure on it. Architect Mick Pearce, together with engineers at Arup and developer Old Mutual Properties, sought a way to maintain comfort in a large commercial building without energy-intensive machines. He studied how termites build mounds that remain livable as temperatures swing between day and night, and appears to have adapted that idea for a building designed for people.


How termite mounds actually stay ventilated

It's easy to think of a termite mound as a natural thermostat, holding a constant internal temperature regardless of the weather outside. The real science is more particular, and more interesting. Researchers Hunter King, Samuel Ocko, and L. Mahadevan directly measured airflow inside active termite mounds for a study in the Proceedings of the National Academy of Sciences, titled "Termite mounds harness diurnal temperature oscillations for ventilation." They found that the mounds exploit daily fluctuations in outside temperature: the thin outer walls heat up faster than the deeper channels, and that temperature differential creates gentle convection currents circulating air up and down through the structure. This cycling appears to help push carbon dioxide out of the nest and regulate its internal climate without termites actively pumping air.

Copying the mound, not just the shape

Eastgate doesn't resemble a termite mound. What Pearce and Arup borrowed was an engineering principle: let temperature differences move air largely on their own, rather than relying mainly on machinery to force air through the building. The design features exposed thermal mass, built-in shading, and air shafts that create a "stack effect," drawing cool air in at the bottom of the building and venting warm air at roof level, much like the tunnel systems inside a termite mound. A series of large, low-power fans in the lower columns supports this airflow rather than replacing it; the building's ventilation is fan-assisted, not fan-driven, with the temperature-difference effect doing most of the work. The lighting follows the same energy-saving logic: luminaires on the office floors automatically adjust to outside daylight levels, cutting electricity use further.

What the numbers actually show

Arup's own project data puts Eastgate's heating-and-cooling energy savings at around 90%. The building is also cited as an example of biomimetic design in a 2025 systematic review in Frontiers in Built Environment, "Application of bionic architecture in low-carbon design: a systematic review from nature inspiration to architectural practice." That review, drawing on 109 studies published between 2010 and 2024, puts typical operational energy savings from biomimetic strategies like termite-inspired ventilation at 30% to 60%. Eastgate's 90% figure, by comparison, comes from Arup's project-specific data rather than the review's broader dataset. That doesn't mean the whole building is run on almost no power. Lighting, elevators, and other systems still require electricity, just more efficiently than they otherwise would.

Why a mall from the 1990s still matters today

Eastgate remains occupied three decades after it opened, and remains one of Harare’s defining commercial landmarks, Arup says. It continues to reference the building as a working benchmark for low-carbon design, rather than a one-off experiment. That durability is part of what makes it so special. Many experimental green buildings from the same period were quietly abandoned or retrofitted with conventional systems. Eastgate was not. Termite mounds have evolved over millions of years to help solve the problem of staying habitable in a changing climate. Eastgate suggests that copying nature's engineering can inform low-energy building design.