It’s Not Rocket Science #9: Natural Ventilation

Dhaka, Bangladesh is at 24.5°N, near the Tropic of Cancer. Its has 60 inches of rain, mostly in the hot and humid summer. Wind is mostly from the south-east.

Wind speed is higher in summer.

It’s no surprise then, that apartments are designed for natural ventilation, and for maximum cross ventilation for bedrooms.

• Typically, there are one, two or four apartments off of a single stair and elevator.
• Apartments usually have windows on three sides which means the stair and landings can be naturally ventilated.
• Additional ventilation on the fourth side is often provided via the open corridor.
• All kitchens and all bathrooms are located on external walls, and have windows. This is the largest difference with a “western” apartment plan that would place them on access corridors walls in order to maximise daylight. Oh OK, “view (= $)”.
• The walls of these service spaces also act as a thermal buffer.
• Bedrooms are located on the outer corners where cross-ventilation is best. This means the living room gets positioned close to the entrance, with the dining area in the middle of the apartment. These spaces are neither dark nor stuffy, but sunlight and view is not a priority.

If the point is to have a good night’s sleep in such a climate and without the use of air conditioning, then there’s a lot that’s right about these apartment plans. The downside is that there is often little distance between living room (and sometimes bedroom) windows of neighbouring apartments.

Here’s a plan by noted Bangladeshi architect Rafiq Azam of Shattoto architects. The principles can still be seen there as the plan hasn’t been completely Westernised.

It’s for a project called Alif Breeze that’s been getting a bit of media attention. And rightly so – it does all the good stuff. 

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Here’s a maxim I just invented: “Behind every successful architect there’s either a successful client or a successful property developer.” Here’s Shattoto’s S.A. House on Archdaily. It looks nice enough, and comes with all the right words.

I much prefer Shatotto’s South Water Caress, again on ArchDaily. Again, it’s doing all the right things. I wouldn’t overestimate the evaporative cooling effect of those signature pools but they at least give the impression of coolth to the people who look at them. Including us. (Although it’s not the done thing in many countries, I wouldn’t underestimate the evaporative cooling effect of hanging laundry outside one’s windows.)

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Exposed concrete frame with brick infill is a nice and inexpensive way to build – especially when you don’t have to worry about thermal bridging. Rafiq Azam would qualify as a misfit were it not for the fact that these techniques are standard practice – a type of modern vernacular, as it were. At least they are for the property developers, the strategically-named South Breeze Housing. Look through their projects and you’ll find Alif Breeze and South Water Caress. Many of their other projects feature the same principles of construction and layout. This tells us that there is a market for apartments that are comfortable to live in.

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You’ll also see Shatotto’s South Water Garden which also does all the right things. It’s probably no fault of the architects that we (and everybody else) can see evaporative air conditioning units for the master bedrooms. The noise of these units will probably force people nearby to do the same. And that will be the beginning of the end of these comfortable and low-energy apartment layouts.

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