Spend five minutes in humid Ho Chi Minh City and you'll probably be running for cover into the nearest air-conditioned refuge.
In the Vietnamese city -- and many developing subtropical countries across Asia, such as Indonesia and the Philippines -- air conditioning (AC) is increasingly being considered a necessity.
But one architecture firm is advocating a different way to keep cool.
T3 Architecture Asia, which has offices in Vietnam and France, specializes in back-to-basics "bioclimatic architecture", which it says could make energy-guzzling AC units redundant.
By harnessing the local topography, climate, and vegetation, as well as cleverly manipulating a building's orientation, the firm can naturally create a comfortable indoor climate.
"It is crucial for all new building designs in cities to encompass bioclimatic architectural features," Myles McCarthy, director of implementation at the Carbon Trust consultancy and research firm, tells CNN.
"As demands in Asian cities for buildings -- both domestic and commercial -- increases, and the need for higher density living continues to climb with urban populations, it will be crucial to ensure this growth does not drive energy and water consumptions higher."
Conditioned to think differently
Charles Gallavardin, director of T3 Architecture Asia, first forayed into bioclimatic architecture in 2005. In cooperation with the World Bank, he built an affordable apartment building in Ho Chi Minh City, which houses 350 families in an impoverished neighborhood where AC bills were to be avoided.
"You don't need to spend money on air conditioning, even in a hot climate like Ho Chi Minh, as long as your building is well designed," Gallavardin tells CNN.
Covered open-air corridors, ventilated roofs, fiber-glass insulation and the use of natural materials meant the Ho Chi Minh City units offered both natural light and ventilation.
"We try to avoid big glass facades facing east or west, because that would make the building like an oven in a tropical climate," he says.
"If you work with the main wind stream and have smart sun protection, you can do it -- you really can design buildings that need no air conditioning in a hot place like Vietnam."
Gallavardin explains that a typical bioclimatic T3 building is naturally about 41 Fahrenheit cooler than the outside temperature, with natural ventilation and the odd ceiling fan doing the rest of the work.
Going back to basics
Since that first project, Gallavardin has built several luxury bioclimatic hotels in Cambodia and Myanmar, a concept restaurant in Ho Chi Minh City, and even his own green office for the T3 team.
Other architects are also experimenting with this style of building.
In Indonesia, Andyrahman Architect's Biophilic Boarding House was shortlisted in the World Architecture Festival's Building of the Year 2016 competition, praised for its perforated walls that help the building stay cool in tropical Surabaya, a congested port city in East Java.
In China, American architecture firm Perkins & Will took a bioclimatic approach to the new Shanghai Natural History Museum -- while the building provides air-conditioning in gallery areas to protect the artwork from humidity, it also has automated windows and skylights to naturally ventilate public areas.
The museum saves 15% on energy consumption compared to a standard-design museum.
Of course, bioclimatic buildings are nothing new.
Before the 20th century, bioclimatic architecture was the norm, and it's still visible today in vernacular buildings from Spanish haciendas to traditional Chinese village homes.
But with the invention of AC in 1902, by Willis Haviland Carrier, in the United States, bioclimatic solutions fell out of favor. Today, heating and cooling systems account for 40% of global building energy consumption, according to the International Energy Agency (IAE), which predicts that by 80% of air-conditioning demand will come from Asia by 2050.
"In (rural areas) of South and Southeast Asia, air-conditioning is not the norm -- but it is becoming more common in city centers, contributing to high energy consumption," Marlyne Sahakian, a research associate at the Faculty of Geosciences and the Environment at the University of Lausanne in Switzerland, who penned "Keeping Cool in Southeast Asia", tells CNN.
"In the Philippines, there was a strong 'West is best' trend, with architecture styles mimicking models from the north western hemisphere, which were not appropriate for the local climate," she adds, citing the "glass tower" model.
Breath of fresh air
Overall, Gallavardin says, Asia has been slow to embrace environmentally friendly building methods.
"What I see in Asia, even in rich countries like Hong Kong or Singapore, is that they love 'green washing.' They put trees on the facade, add solar panels and call it a green building.
"But when you look a bit closer, it's not really that green -- sometimes it's the opposite. We will see more truly energy-efficient buildings in Asia in the future, but it's very slow still."