Before air conditioning (BAC): How did we ever keep our homes cool in the sweltering heat?

Image courtesy of Pexels, Dương Nhân

There is no doubt about it. Air conditioning is great. It is simple, it works. All we have to do is touch a button and arrange for someone to swing by for a regular checkup. And in today’s extreme hot climate, who can imagine being without it? But (you heard it coming) with its popularity, also come reports about drawbacks: For our health, such as sick building syndrome, and for the planet.

From: “The fluid in our AC is thousands of times worse than CO2” to: “Special chemicals that make it work are actually extremely hazardous to the climate.” From: “Refrigeration chemicals are a nightmare for the climate” to: “Experts say alternatives must spread fast.” And: “Synthetic, factory-made gases” in air conditioning “have extremely significant global warming potential.” These are just some of the reported downsides of cooling in this way.

Loops and blind spots

Dr. Radhika Khosla, Research Director of the Oxford University India Centre for Sustainable Development, is one of the increasing numbers of experts who talk about these drawbacks. She has written about the issue of a feedback loop on the World Economic Forum site. It’s when the increasing air condition’s demand for energy is upping global warming and this is upping the need for more air conditioning.

Others talk about a ‘blind spot’ when it comes to energy systems around the world. Take International Energy Agency (IEA) Executive Director Fatih Birol, who has called the growing demand for air conditioners: “one of the most critical blind spots in today’s energy debate.” The IEA Future of Cooling report itself states that our global use of air conditioners and electric fans make up 20% of the total electricity used in buildings.

“The growing demand for air conditioners is one of the most critical blind spots in today’s energy debate.”

Global warming: A new cooling reality?

So, by cooling our homes in this way, experts say we are “making the world hotter and more unstable.” And clever people are looking for sustainable cooling alternatives. Phasing out air conditioning and coolants is something that simply needs to happen. Says for example the Environmental Protection Agency (EPA). Meanwhile, new initiatives are taking the lead in different ways of thinking when it comes to cooling our buildings.

Take the India Cooling Action Plan (ICAP). This special scheme is located in one of the historically hotter parts of the world. It “includes better city planning and building design, and it will embrace novel coolants,” said Stephen Andersen of the Institute for Governance & Sustainable Development, warning that “emissions of potent greenhouse gases are likely to skyrocket.”

Dr Radhika Khosla too has also co-created a framework to help initiatives on their way with such novel cooling solutions.

Passive cooling, not global warming

But hang on a minute. What if we could cool our homes without all those drawbacks for us and the world? Enter a scenario. Imagine going into a home in the heat of the desert. It is so cool inside you think it is air conditioned. But it is not! For centuries, cultures around the world have used passive cooling methods in their homes.

Unlike air conditioning, passive cooling forms do not require electricity, technology or chemicals. They do not cost as much (or anything) to purchase or maintain, there are no electricity bills. There is nothing to link them to anything nasty. We know passive cooling as a way that uses what is already there. No strings attached. For example, by making clever use of a free and sustainable breeze. Or through the special architecture of a building.

Summer salvation in the heat of the day

What’s more, it turns out passive cooling methods can be very effective. In Morocco, for example, experts looked at clay-straw buildings that incorporate passive cooling techniques in the heat of summer. Compared to Moroccan concrete villas without such passive cooling techniques, these traditional homes have shown a 5°C reduction in indoor temperatures. As well as a reduction in energy demand by 65%, and a decrease in the number of hot, uncomfortable hours by 25%.

Such data could show us that there are things we can do ourselves. It could start with the way we build our homes: to facilitate natural, passive cooling. Like we used to: have archways, large windows, and high ceilings to help create cross ventilation, and porches and trees on the east and west side of homes for shade. We can use materials such as wood, or even cross-layered timber, with a thick structure all around, to keep our home cool in the summer and warm in the winter.

We tend to want to open our windows during the day when it’s hot. But we could also create shade and keep the night’s cool inside as long as we can. We can do things to create natural airflow or, for example, refrain from cooking during the day. Perhaps every little thing helps. And perhaps, we can ultimately cool our homes without needing any electricity.

The land of make belief

Granted, this might be hard to imagine on a day when heat seems to gather and surround us. But do we dare to imagine? Do we dare to learn from age-old passive cooling methods for today and for the future? Is all of this really just an imaginary world of make-believe?

Experts such as Energy Digital Magazine are here to remind us of something. “Before the days of air conditioning, refrigerators and electrically powered fans, passive cooling techniques were used in architecture as salvation from the summer’s sun,” they said. Adding that today, such ancient cooling designs are starting to become popular for their insights they can give us.

“Before the days of air conditioning, refrigerators and electrically powered fans, passive cooling techniques were used in architecture as salvation from the summer’s sun.”

Fighting heat: A shift in perspective

Over in China, green roofs have helped reduce average land surface temperature by 0.91 °C, Dr Radhika Khosla pointed out when talking to us. And according to the creators of her own framework, there are things city developers can do too. They can incorporate passive embedded urban solutions, such as greening cities through street trees, green façades and green roofs.

Some say that air conditioning and central heating systems are there to compensate for the shortcomings in the way we build our homes. Perhaps ancient passive ways of cooling can also help us change the way we do so in the future.

Dr Khosla told us: “A shift in perspective comes from recognising that we have many ways to stay cool and achieve thermal comfort. Ways that don’t require air conditioning.” She added: “Such passive solutions, including shading and ventilation, have been available to us for generations. They allow for a much more sustainable cooling, energy and climate future.”

“A shift in perspective comes from recognising that we have many ways to staying cool and achieving thermal comfort.”

Passive cooling around the world

How did buildings keep cool in the heat of the day before the invention of air conditioning? People are asking this question more often today.

Stepwells: a thousand steps

First, we could head over to India. It is known for its traditional stepwells. Designed in protection of (desert) heat, but also used for crop irrigation and in times of drought, these structures were an integrated feature in a building. With a cooling pool of water at its base, encased by a tall set of steps, stepwells provided areas where people could swim, bathe and perform religious rituals. Lavishly ornamented, sometimes they were surrounded by thousands of symmetrical, narrow steps.

They say one of the first Indian stepwells was developed around 1,500 years ago. But even today, ancient stepwells are keeping some buildings cool. One of Rajasthan’s most ancient architectural buildings for instance, where such a structure in the Pearl Academy of Fashion is said to keep indoor temperature 20 degrees cooler than out.

Windcatchers

For centuries, people in hot areas such as Iran, Egypt, India and Africa have used windcatchers. Over in Australia they might refer to them as windtowers. In Sydney they are considered particularly effective.

Windcatchers and their natural airflow, ventilation and thermal comfort are known for being among the most ancient and effective forms of passive cooling. There are many different designs, and they can be a kind of tower or chimney inside someone’s home. We also know windcatchers as icons of Iranian culture. In fact, one of Iran’s major cities, Yazd, is called the City of Windcatchers. People had to create them long before air conditioning, and it took creative thinking in a world before electricity.

Skywells

Over in China, there are reports how people are constructing more buildings according to traditional skywells designs today. How they are keeping Chinese homes cool in today’s heat. The ancients have much to tell us, writes one news network about such tall, narrow courtyards found in China. Scientists are looking into how downdraught cooling such as skywells can be used for today’s alternative solutions.

Perforated building facades

Perforated exteriors of buildings, also known as breathing walls or ventilated facades, too make use of passive cooling. You can find them around Mediterranean regions and Asia, as well as the Middle East and North Africa. Such structures allow people to control airflow and create an optimal indoor air quality. They can leave humidity and pollutants outside. As well as the looks of curious neighbours, as screens such as these can add a level of privacy.

Bamboo cooling

Developers are also creating newer passive cooling methods today. Such as an urban cooling bamboo system, which uses hot air, water and… bamboo. Experts say this system can be useful even in the toughest of heat waves.

Alternative systems

There are also other reports about substitutes to air conditioning. Take swamp coolers which can be used in dry climates. Then there is geothermal cooling, described as renewable energy systems that “move heat from a building to below the earth’s surface, using the ground like a heatsink.” Plus, residents are using radiant cooling systems in North America, which circulate chilled water at the ceiling of a building.

Construction gone wrong

To demonstrate the power of passive cooling, we can also look at things from a different perspective: in case something goes wrong, and instead of cooling, some form of heating accidentally occurs. In fact, there are stories from all over the world of buildings whose construction is so flawed that its passive effect is even dangerous!

A famous example of this is the Walky Talky skyscraper building in London, where a 36-storey facade creates extreme downdrafts, said to be capable of knocking over pedestrians below, and where coffee shop signs fly through the air. It’s also where Londoners’ parked cars and bikes melt. This is due to the building’s concave glass structure, which acts like a burning glass and can cause local temperatures of 90 degrees.

The building is now so famous that it is known for stories of people frying eggs on the ground nearby.

Every little bit helps?

Making our own cooling system with plastic bottles, or by placing ice in front of a fan.

Getting a ceiling fan that spins counterclockwise.

Placing fans in ways that together they create an air stream or cross breeze.

Making use of kitchen or bathroom extractor fans to help carry out some hot air.

Opening windows from the time it gets cooler outside than in. But keeping curtains closed from morning until it gets hotter outside to keep cooler air in.

Blinds, shades, cloth or shutters on the outside of the window can help block heat before it reaches your home.

Getting special, heat blocking or reflective, lined curtains.

Using cotton sheets at night.

Put your socks in the fridge for a bit before you wear them!

Placing wet curtains in front of open windows.

Creating shaded areas outside, with more shutters, trees and tall plants and shrubs.

Refraining from cooking and using lights during the day.

Greening our roofs and buildings.

Getting indoor cooling plants that release moisture from their leaves as temperature rises. Take ficus, aloe vera, snake plant or bamboo palm.