Glass fever heats up Dhaka city

The increasing use of glass in new buildings, particularly in upscale parts of Dhaka, is contributing to a rise in the city temperatures, with negative consequences for residents and the environment.

Environmentalists, architects and urban planners have called for a more considered approach to glass usage, especially in all-glass skyscrapers. These buildings require a massive energy flow to maintain a cool internal environment.

This energy, primarily used to power air conditioners, is associated with high levels of carbon emissions. A recent study suggests that the building sector is responsible for around 40 per cent of global carbon emissions.

Since 1948, Bangladesh experienced its longest heatwave on record in April this year. According to the Bangladesh Meteorological Department, this year's unprecedented extreme heat affected nearly 75-80 per cent of the country.

After a brief respite in the first week of May, the Met Office now forecasts a renewed rise in temperatures.

Professor Ahmad Kamruzzaman Majumder, chair of the Department of Environmental Science at Stamford University, is leading an ongoing study that has found a 2°C temperature increase in areas dominated by glass-walled buildings.

He said new buildings in Dhaka's upmarket areas such as Dhanmondi, Motijheel, Uttara, Gulshan and Banani have heavily used glass walls over the past decade.

"Our study found that 70-80 per cent of new buildings in these areas have glass facades covering at least 60 per cent of their exterior," he told The Financial Express.

Buildings with extensive glass facades require more energy, mainly for air conditioning, to maintain a comfortable internal temperature.

Citing a previous 2019 study, Professor Majumder said, "We found that over 100,000 air conditioners are in use across 1068 apartments in the Dhanmondi area alone."

Besides, extensive glass facades can cause visual disruption for pedestrians and vehicles due to reflections of daylight and sunlight. These structures can be disorienting for birds, he added.

The rise of unnecessary glass in country's hot climate

The use of glass as a building material in Bangladesh first emerged in the 1980s and has since seen an indiscriminate rise.

Experts are now questioning the suitability of this trend for a country with a tropical monsoon climate characterised by hot and rainy summers and dry winters.

Mohammad Fazle Reza Sumon, a planner and immediate past president of the Bangladesh Institute of Planners (BIP), said extensive use of glass facades is more common in countries with colder climates, where it helps retain heat inside buildings.

"Glass-covered buildings are typically found in countries with mostly cold weather to keep the interior warm," he said. "However, a country like Bangladesh, which passes long, hot summers, requires additional energy to cool these structures."

Sumon objected to blindly imitating Western architectural styles without taking local weather conditions into account.

"There seems to be a habit of copying Western architects and designs without adapting them to our local environment," he said.

The planner advocated for prioritising other considerations and using glass judiciously, as he pointed out that city regulations recommend maintaining at least 25 per cent greenery on a building's footprint.

"Dhaka is fast becoming a concrete jungle," he said. "We have land development rules, but enforcement seems lacking. Buildings often deviate from the plans approved by the Rajdhani Unnayan Kartripakkha (RAJUK)."

"RAJUK doesn't seem to be enforcing its own regulations."

Benefits of glass-fronted buildings

Architects say building owners and developers often prefer designs that offer several advantages: reduced base weight, increased usable space, lower maintenance costs, manageable temperature control and overall cost-effectiveness.

Md. Asifur Rahman Bhuiyan, additional chief architect at the government's Department of Architecture of the Ministry of Housing and Public Works, said glass can deliver all these benefits with relatively short construction times and minimal effort.

"There is a wide variety of glass available and ongoing global research looks to make it even more cost-effective and environmentally friendly," he said. "By using cutting-edge glass technology, these structures can become more environmentally sustainable than traditional buildings."

Mr Bhuiyan highlighted the key advantages of glass-fronted buildings.

Those include increased usable space, reduced weight, lower maintenance costs, and faster construction times.

He said cleaning skyscrapers is easier with extensive glass facades. These factors, he noted, are driving the global trend towards glass-heavy construction.

Double-glazed panels, with gas filling the gap between the panes, can help regulate internal temperature, reducing reliance on air conditioning.

Opening windows in high-rise buildings can be unsafe due to high air pressure, according to the additional chief architect, while glass facades offer a solution in such cases.

However, He, too, called for using glass judiciously to avoid negative environmental impacts.

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