Rethinking Dhaka’s homes in an age of heatwaves
With heatwaves intensifying, Dhaka’s high-density housing model is under strain. Reduced setbacks, limited cross-ventilation, and heat-absorbing façades have weakened passive cooling strategies—exposing the gap between rapid urbanisation and climate-responsive design
If you have ever lived on the top floor of any building in Dhaka, you would know how the heat feels in the afternoon. It feels like living inside a grill while the ceiling fan pours in hot air, broiling the skin.
As heatwaves grow longer and more punishing, Dhaka's buildings are being tested in ways they were never designed for. Step outside on an April afternoon, and the city feels like a heat trap—concrete walls radiating heat, narrow streets blocking airflow, glass façades turning apartments into ovens. The question is no longer whether heatwaves will intensify, but whether our homes are ready.
Architect Abu Sayeed M Ahmed believes the answer, at present, is uncomfortable.
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When asked if Dhaka's buildings are even ready for heatwaves, he said, "In most cases, no."
Abu Sayeed draws a striking comparison between two very different buildings: the historic Ahsan Manzil and the National Parliament complex (Jatiya Sangsad Bhaban).
Ahsan Manzil, built in the 19th century, features deep white verandas that prevent direct sunlight from hitting the exterior walls. "Even above the verandas, there were sunbreakers—louvre-like elements—so that direct solar radiation could not enter," Abu Sayeed explains. "This was ancient wisdom."
Traditional houses once used khorkhori (louvred) doors and windows, allowing air to flow in while filtering harsh sunlight. High ceilings, often 13 to 14 feet, allowed hot air to rise and escape through ventilators. Walls were thick, shaded, and designed for cross-ventilation.
In other words, climate-responsive design was embedded in architecture long before air conditioners arrived.
The Parliament complex, designed by Louis I. Kahn, offers a modern interpretation of similar principles. Abu Sayeed points to its layered envelope and shading strategies. "There are double layers, shaded openings, and roof systems that reduce direct heat gain. These ideas are very relevant for public buildings."
Yet, as Dhaka modernised, much of this climate intelligence was sacrificed.
Density versus liveability
The core problem, Abu Sayeed argues, is not ignorance—it is economics.
"Dhaka is now economy-driven," he says. "Land prices are so high, and density is so extreme, that everyone wants to maximise built-up area."
Setbacks are minimised. Balconies shrink. Sunshades disappear. Developers squeeze out every extra square foot to make projects financially viable. "If adding a sunshade reduces even one square foot of saleable area, many will avoid it," he says.
The result? Buildings pressed tightly against each other, blocking airflow and daylight. In some cases, restrictions on high-rise construction have ironically worsened the situation. "If you build low-rise, four-storey buildings very close to each other, where will light and air come from?" Abu Sayeed asks. "If you go higher on larger plots, you can leave more open space around."
In his view, climate resilience cannot be separated from planning reform. Without addressing land economics and density management, expecting widespread adoption of heat-resilient features is unrealistic.
"You cannot make laws that people cannot follow," he says. "If compliance is impossible, people simply won't comply."
Double roofs and ventilated layers
Among the most effective passive cooling strategies, Abu Sayeed highlights double roofs—or ventilated roof systems.
He cites the Teacher-Student Centre (TSC) at the University of Dhaka as an example. "At TSC, there is a roof above the main roof. The idea is that direct heat should not strike the slab. The upper layer absorbs and disperses heat, while air flows in between."
This buffer zone reduces heat transfer into interior spaces, lowering indoor temperatures without mechanical cooling.
But why are such systems rare in private housing?
Because building codes often count these features within floor area calculations. "If a double roof is counted in the total buildable area, developers lose saleable space," Abu Sayeed explains. "Then they will not do it."
The solution, he suggests, lies in policy reform. Instead of penalising climate-responsive design, codes should incentivise it.
"For example, you could allow an extra floor if the building meets energy-efficient criteria—double roofs, shaded façades, proper setbacks," he proposes. "If you give something in return, people will follow."
Incentives, not just mandates, could shift the market.
What about evaporative cooling?
Evaporative or water-based cooling systems are often suggested as low-energy alternatives. But do they make sense in humid Dhaka?
Abu Sayeed is cautious.
"Our traditional buildings already used natural ventilation," he says. "Hot air rises. If ceilings are high and there is a ventilator, that hot air can escape."
However, many modern commercial buildings now have false ceilings, reducing the height to eight or nine feet. "There is no space for hot air to accumulate and exit. We are creating artificial environments."
While mechanical cooling—air conditioners and other systems—can provide immediate relief, Abu Sayeed questions their long-term health implications and energy burden. "Artificial cooling can improve comfort temporarily," he says, "but whether it is healthy in the long run is always questionable."
In Dhaka's humid climate, evaporative cooling has limitations unless it is carefully designed. Once again, passive strategies—shading, ventilation, and height—may offer more sustainable gains.
Abu Sayeed believes public buildings should lead by example.
"In public projects, land constraints are usually less severe," he notes. "Ventilated façades, shaded corridors, double roofs—these should be mandatory."
Private developments, however, require a different approach. Simply imposing stricter environmental codes without financial feasibility will backfire. "You cannot expect people to sacrifice their investment without compensation," he says.
The answer may lie in hybrid solutions—combining passive and active systems in cost-sensitive ways.
Can middle-income families afford heat-resilient homes?
A common perception is that climate-responsive architecture is expensive—a luxury for high-end projects. Abu Sayeed challenges that notion.
"In villages, mud houses are very affordable and naturally cool," he says. "Even traditional bamboo or timber houses allowed good ventilation."
The problem is not affordability in principle, but urban real estate economics.
On dense city plots, achieving proper ventilation and shading becomes difficult. For lower- and middle-income households, a fully passive model may not be feasible. But hybrid approaches—partial ventilation strategies, selective shading, strategic orientation—could make a difference.
"If we combine some natural systems with necessary artificial cooling, it can become affordable," Abu Sayeed says. "Otherwise, it will be very difficult."
Rethinking Dhaka's future skyline
The conversation around heatwave-resilient architecture is not merely about design aesthetics. It touches on planning laws, economic incentives, density management, and public health.
Dhaka's older buildings quietly demonstrate that climate-responsive design is not new to this region. Verandas, sunshades, cross-ventilation, and high ceilings were once standard. Modern landmarks such as the Parliament complex demonstrate that contemporary architecture can reinterpret those ideas at scale.
Yet much of today's housing stock moves in the opposite direction—sealed, compressed, and reliant on air conditioning.
Abu Sayeed's message is clear: climate resilience cannot remain at the level of theory.
"If we incorporate these principles into the building code properly," he says, "energy-efficient buildings are absolutely possible."
