The Problem (and Opportunity) of A/C

By Timothy Beatley

The world is poised to dramatically increase its use of air conditioning, with serious ramifications for energy consumption and climate change. In their recently published report The Future of Cooling, the International Energy Agency predicts that, without significant policy intervention, energy consumed for space cooling will likely triple by 2050. That means the number of air conditioning units will likely increase from today's 1.6 billion to 3.7 billion.

This alarming report concludes that "[a] concerted policy push to rein in cooling energy demand is needed urgently." Many things can be done, the IEA says, including mandating new, more stringent energy standards for air conditioners, efficiency labeling, and design of more energy-efficient buildings.

To this, planners must also add their efforts: more abundant use of the shading and evapotranspiration benefits of trees, better placement and design of buildings to maintain breezes and airflow, and other creative ways cities can take advantage of local cooling opportunities.

Singapore's Oasia Hotel has reduced its air-conditioned area by 25 percent by opening areas like reception to the outdoors. Photo by K. Kopter.

Singapore's Oasia Hotel has reduced its air-conditioned area by 25 percent by opening areas like reception to the outdoors. Photo by K. Kopter.

A much-needed update

The biggest game changer would be changes in the technology itself, something that hasn't happened much since Willis Carrier stumbled upon the invention of air conditioning in 1902. One encouraging initiative is the soon to be launched Global Cooling Prize, spearheaded by the Rocky Mountain Institute. I spoke recently with RMI Principal Rushad Nanavatty about this new competition and what it will hopefully accomplish.

The stakes are very high, he says: A business-as-usual growth in air conditioners has the potential to eat up as much as half the climate emissions the planet can afford to emit if there is any chance of keeping temperatures under two degrees centigrade (the goal of the Paris Agreement). It's a problem that can't be seen or experienced in the way that a coal burning power plant might. "It's currently invisible, because the bulk of the demand is just over the horizon in places like India and China," says Nanavatty.

But the potential to dramatically shift the technology is great. "This is not an industry that has, to date, had to invest very much in research and development and innovation at all," Nanavatty says. "The vapor compression technology that sits at the heart of these room air conditioners, you can argue, is fundamentally unchanged from when it was really discovered by accident by Carrier over 100 years ago." This is evident in comparing the industry with efficiency advancements in renewable energy, say solar photovoltaic panels, or with lighting, like LEDs.

The competition was launched in November and will stay open for two years. The ultimate winner will receive a prize of $1 million, and another $2 million will be distributed amongst shortlisted teams. The technology must meet certain prize criteria, including having five times less climate impact and costing no more than twice the cost of current air conditioning units. The competition is being funded through a combination of philanthropic and government sources, including a $2 million contribution from the Indian government. There is real potential to change the technology and industry with a little nudging.

International solutions

The health and quality of life benefits to be had from air conditioning, especially in the hottest parts of the world, are real; it is unfair to simply advocate restraint in those places. And it is useful to know that the U.S. went from air conditioning in 13 percent of homes in 1960 to more than 90 percent today.

That said, there are also clear opportunities in every country and region to rediscover the vernacular architecture and traditional building techniques that preceded the global addiction to air conditioning: a return to designing for deep shade, natural ventilation, buildings that use the stack effect (taking advantage of the fact that warm air rises) to generate natural air flow, and ancient techniques of evaporative cooling like "stepwells" — small, submerged pools of water, reached by steps, that store water but also provide evaporative cooling.

Brisbane, Australia, is beginning to return to design principles found in the traditional Queenslander house. This form of vernacular architecture suited the subtropical climate well: elevated single- family homes with wide wraparound verandas, tall ceilings, and windows and doors designed to stay open to capture breezes. The city recently adopted a design manual emphasizing a return to these principles. Construction has even started on a high-rise residential tower there incorporating many of these ideas, including cross-ventilated apartments and shaded balconies. The result of a design collaboration between two firms, Architectus and WOHA, the vision for 443 Queens Street is described on its web page as an "open, breathing building" that will rethink the "traditional high-rise design of sealed, hermetic towers" to "[engage] with the environment."

In July, I stayed at an unusual high-rise hotel in Singapore that offers additional insights about what can be done. At the Oasia Hotel, another design of WOHA, there was an effort made to reduce the extent of air-conditioned space in the building. Guests arrive by elevator to check in on a sky park level completely open to the outdoors. Overall, this design has reduced the air-conditioned area of the building by 25 percent, and in the process, has created some remarkable outdoor areas that are actually cooler (and subject to more soothing breezes) than what can be experienced on the street level below. Oasia's most distinctive feature is its exterior cladding, which turns virtually the entire exterior of the structure into a growing space, boasting 21 different varieties of flowering vines, so many that something is always in bloom. This also provides shade and cools the underlying walls, reducing energy consumption.

'Thermal delight'

It is worth reflecting on what we lose by living and working in hermetically sealed, highly air-conditioned homes and offices, enjoying (or is it enduring?) spaces where the temperature remains unnaturally constant over the course the day.

I grew up in northern Virginia without any form of air conditioning, but with lots of trees around us, and the ability (and need) to keep our windows open throughout the summer months. We could hear birds and katydids and tree frogs, adding immensely to the pleasure and delight of living in the world.

Some of this is what Lisa Heschong calls "thermal delight" in a 1979 MIT Press book by the same title that has since become an architectural classic. She believes we have a separate "thermal sense," "like sight or smell, although it is not normally counted in the traditional list of five sense." Thermal sense, Heschong says, is a "sense of warmth and coolness," and there is a pleasure and delight from experiencing it — something we should take into account when we design buildings and cities. But it's hard to allow for thermal delight when we are all sitting in climate-controlled buildings.

Tackling the growth of air conditioning will require significant and rapid improvements in technology, and the Global Cooling Prize should help to stimulate this shift. But we must also keep in sight the many ways that designing with climate and questioning the modern notions of indoor comfort might deliver other important benefits and experiences — including connections to the natural soundscape around us, the birdsong and crickets and other deeply soothing sounds we once coevolved with.

Timothy Beatley is the Teresa Heinz Professor of Sustainable Communities at the University of Virginia, where he directs the Biophilic Cities Project.