Designing for Dhaka's Heat: Passive Cooling That Actually Works
In Dhaka's climate, the difference between a comfortable building and an expensive one is decided long before anyone turns on a cooling system. It is decided in orientation, in window placement, in the depth of a balcony. Yet cooling is too often treated as an equipment problem to be solved with tonnage, rather than a design problem to be solved on paper.
Start with the sun, not the plan
The western sun is the single largest heat source any Dhaka building faces. A west-facing wall that receives direct afternoon exposure will radiate heat into the interior for hours after sunset. West and south-west glazing should be minimized or deeply shaded; long windows oriented north bring in consistent light without the associated heat load.
- Deep balconies and vertical fins shade glazing without darkening rooms
- Cross-ventilation requires inlet and outlet on opposite faces — a corridor plan with windows on one side cannot breathe
- Light-colored external finishes reflect far more radiation than they cost in aesthetics
- Roof insulation is the cheapest cooling you will ever buy per taka spent
The most efficient Air Conditioning system is the one the architecture made unnecessary.
Ventilation is a plan-shape decision
Many Dhaka apartments are plan-locked against ventilation: all rooms open onto one side, so air has nowhere to travel. Even a modest rearrangement — placing kitchens and bathrooms to create a pressure path through living spaces — changes how the home feels in April and May. These decisions cost nothing at design stage and are almost impossible to retrofit.
None of this means abandoning mechanical cooling. It means sizing it for a building that is already doing most of the work — smaller systems, lower bills, longer equipment life. That is what designing for the heat actually looks like.
