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Episode
211

The Rise Of Air Conditioning

Nov 16, 2021
How Stuff Works
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23
minutes
Weird history
Romans
USA
Business
Kings & Queens
20th Century
City life
Consumption
Economics

It has gone from luxury to necessity, and there are over 2 billion air conditioning units in the world today.

In this episode, we'll take a look at how air conditioning got started, why people didn't mind being hot in the past, and what the true cost of staying cool might be for future generations.

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[00:00:00] Hello, hello hello, and welcome to English Learning for Curious Minds, by Leonardo English. 

[00:00:11] The show where you can listen to fascinating stories, and learn weird and wonderful things about the world at the same time as improving your English.

[00:00:21] I'm Alastair Budge, and today we are going to be talking about Air Conditioning.

[00:00:27] Now, for many of you air conditioning might not seem like anything special. For billions of people around the world it is an effective way to regulate the temperature, keeping us cool and comfortable when we would otherwise be too hot.

[00:00:44] Indeed, for a large proportion of the developed world air conditioning has gone from a luxury to a necessity, and an American household is more likely to have air conditioning than a dishwasher or a dining room.

[00:01:00] But it most certainly hasn’t always been this way. 

[00:01:04] So, in today’s episode we are going to go on a tour of the rise of air conditioning, from how humans used to regulate the temperature to Dutch magicians playing tricks on British kings, from one of the founding fathers of the United States through to how the air conditioning unit became an integral part of our lives, changing our cities, countries, planet, and even reproductive habits.

[00:01:32] It is a fascinating story, so let’s get right into it.

[00:01:37] The desire to stay cool is, of course, nothing new. 

[00:01:43] The ancient Egyptians and Romans employed various techniques to cool down their buildings from the outside heat.

[00:01:52] Some people have even claimed that the first air conditioning unit was invented in ancient Egypt. The ancient Egyptians would hang wet reeds, wet plants, outside their windows, and when the air came into the house it would be cooled by the moisture on the plants. 

[00:02:13] The Romans understood that if they could bring cold water via aqueducts under their houses, then the temperature inside would fall, it would get colder. 

[00:02:26] And if we really stretch the meaning of the phrase “air conditioning”, then hand fans have been used since the dawn of time. People realised that they could move air by waving something and it would temporarily cool them down.

[00:02:45] The Chinese inventor Ding Huan went a step further in the second century and invented a rotating fan, similar to fans we might see today, although it was manually powered by unfortunate prisoners.

[00:03:01] But there is a limit for quite how much the temperature can be reduced by natural means, either by bringing cold water to a hot place or by fanning oneself.

[00:03:15] There was also, in much of the western world at least, a fear of trying to create artificial cold. 

[00:03:24] Cold was something that people didn’t really understand, and was thought to be something that only God could create. 

[00:03:34] People had no problems with artificially heating a room, by creating a fire, for example, but there was a fear about creating cold in an unnatural way.

[00:03:47] The author Tom Shachtman, in his 1999 book “Absolute Zero and the Conquest of Cold” suggests that this was because it was obvious how to create heat - you would simply start a fire, add wood to it, and ta-da, you could heat a room. But cold was more mysterious. 

[00:04:10] It was thought to have come from a mysterious place far to the north of Britain called Thule, and interfering with the creation of cold, at least in an artificial way, would be interfering with God.

[00:04:27] Some noblemen in Britain might have kept ice in ice cellars deep underground, and you might quite rightly joke that Britain was not exactly the country with the greatest need to lower the temperature, but even in warmer, equally developed countries there was a lack of understanding about, and even interest in, how temperatures could be lowered.

[00:04:54] One of the first records of an inside temperature being lowered by artificial methods actually comes in 1620, and involves a mysterious Dutch man called Cornelis Drebbel, who was a sort of magician, and the first King of a united England and Scotland, King James I.

[00:05:16] The Dutchman Drebbel had claimed that he was able to reduce the air temperature, and the king decided to put him to the test. He challenged him to do it in the Great Hall of Westminster Abbey, a room which would have been one of the largest in the country at the time and still is very large even by today’s standards.

[00:05:41] It was a hot summer’s day, and when King James entered the room he was surprised to find that it was indeed very cold. So cold, in fact, that he had to quickly leave because it was too cold for him.

[00:05:57] No records exist of exactly how Drebbel did it, but historians are fairly sure that he would have placed long trays where he knew the King would enter the room, filled them with cold water from the river Thames and ice, and then mixed it with salt and something called nitre or saltpeter, the mineral form of potassium nitrate.

[00:06:24] The addition of the nitre would have created a chemical reaction that reduced the temperature below freezing point, below zero, and cooled the air above the trays.

[00:06:38] Drebbel knew that cold air displaced hot air, it moved hot air, so the hot air would rise up, meaning that the cold air would stay relatively low, directly where he thought the king would pass.

[00:06:53] Just as Drebbel thought, the king entered the room and walked through the patch of cool air. The king would have assumed that the entire room had been cooled, whereas the reality was that just a small proportion of it would have been.

[00:07:11] Although this would have been a pretty cool trick, it wasn’t a sustainable long-term solution to reducing the temperature inside buildings.

[00:07:21] Scientists continued to experiment with chemical methods of reducing the temperature, and it was even a subject of great interest for one of the founding fathers of the United States, the polymath Benjamin Franklin, in the 1750s.

[00:07:38] His interest in the subject, reportedly, came from an experience that you may well have had. 

[00:07:45] One hot July day in Philadelphia, Benjamin Franklin, so the legend goes, was sitting at his desk writing. He was sweating a lot, and got up to change his sweaty, wet shirt.

[00:08:01] When he put on his fresh, dry shirt it felt hotter than the wet one he had taken off.

[00:08:09] He thought that perhaps this had something to do with the liquid evaporating, so he conducted a series of experiments. 

[00:08:19] He put various different materials on a thermometer and observed what happened when they evaporated.

[00:08:27] Sure enough, evaporation caused the temperature to reduce, and Franklin even observed that, "From this experiment one may see the possibility of freezing a man to death on a warm summer's day."

[00:08:28] The 19th century saw the arrival of more cooling technologies, including the creation of an ice making machine. Primitive versions of “air conditioning” could be created by pumping air over ice, but there wasn’t really a mass-market use case for this, and it was very expensive to do.

[00:08:28] Strange enough as it might seem to us now, there is simply not much evidence that people were shouting out for cooler temperatures inside. It was just accepted that on warm summer days you would be hot and slightly uncomfortable. 

[00:09:23] Houses would be cooled through natural means, by not allowing hot air to come in in the first place, and by using ventilation.

[00:09:34] The first air conditioning unit as we would know it only came in 1903, and was developed by an American man called Willis H. Carrier. He was asked by a printing company to create a machine that would regulate humidity in the building. 

[00:09:54] In the summer months the air inside the building was so humid that the paper would shrink, it would reduce in size. Of course, this was hugely disruptive to the operations of the printing business.

[00:10:10] Carrier created a machine that used a system of fans to blow over coils, small tubes in a ring, which would be filled with cold water.

[00:10:23] As the humid air moved over the cold coils, water would be removed from the air and the air temperature would fall, so when this air was blown out it was colder than before. What’s more, it also reduced the humidity.

[00:10:42] Bingo, Carrier had just invented the air conditioning system. Indeed, the majority of the 2 billion air conditioning units that exist globally today still work on a very similar principle - pushing air over something cold.

[00:11:00] The publishing company was very happy with Carrier, and he quickly patented his invention and created a company, a company that actually still exists today, is worth $50 billion and employs 56,000 people worldwide.

[00:11:18] But while you might think it was an immediate success, and Carrier was off to the races with his new invention, he wasn’t.

[00:11:28] The public took a lot of convincing that this was something that would actually benefit them. 

[00:11:35] The initial uses of air conditioning units were primarily in places like hospitals, and there was very limited personal use.

[00:11:45] The first contact that most Americans would have had with air conditioning was in movie theatres, in cinemas. 

[00:11:54] As you might imagine, small closed rooms with lots of sweaty people smoking for extended periods of time had pretty horrible, sticky air.

[00:12:07] Starting in the 1920s American cinemas started to use air conditioning systems to cool down their cinemas in the summer, making them significantly more pleasant places to be and attracting consumers who would have been put off going by how hot and sticky they were.

[00:12:28] The Great Depression and the Second World War put a dent in the adoption of air conditioners, but the post-war period in the United States was boom time for all sorts of consumer electronics, and air conditioners were no exception.

[00:12:46] This was helped by the price reducing dramatically. In 1932, when the first personal air conditioning units came on sale, they cost today’s equivalent of anywhere from $120,000 to $600,000. Obviously that put them out of the reach of everyone but the very richest - it was the equivalent of employing your own group of servants simply to follow you everywhere with a large fan.

[00:13:19] When Carrier first went on tour with his air conditioner units, it took a while for the American public to believe that they actually worked, and there are photos of him doing stunts like going to a fair and creating an igloo full of ice, which was cooled down of course by his air conditioning units.

[00:13:42] The marketing tricks worked, and more and more Americans decided to buy this latest must-have modern convenience. 

[00:13:51] By 1960, 12 percent of U.S. households had air conditioning. 20 years later, in 1980, it was 55 percent; now it’s 90 percent, only just behind Japan where 91% of houses have air conditioning.

[00:14:10] The rest of the world is following suit

[00:14:13] 60% of households in China now have AC, up from less than 8% in 1994.

[00:14:22] But the reality is that most households in hot countries, the households where the need to be cool is the greatest, don’t yet have an air conditioning unit.

[00:14:34] Fewer than 5% of households in India have air conditioning, 9% of households in Indonesia and 16% of households in Brazil have it.

[00:14:46] And by 2050 around 2/3 of the world’s households could have an air conditioner, according to the reports by The International Energy Agency.

[00:14:58] Now, let’s take a moment to think about the impact of this, the good, the bad, and the unexpected.

[00:15:06] So, the good. Purely on a personal human comfort level, it makes indoor life more manageable when it’s hot outside. 

[00:15:16] It is also hugely important in places like hospitals, where having a constant temperature is important for patient health.

[00:15:25] Being able to easily, quickly and cheaply reduce the temperature literally saves lives. Every year during heat waves people, normally older people, unnecessarily die at home, and air conditioning reduces the risk of this happening.

[00:15:43] So far so good.

[00:15:45] Before we get to “the bad”, let’s look at the unexpected, or perhaps indirect and not so immediately obvious.

[00:15:55] To understand this, it’s most helpful to look at the situation in the United States, since that is the country with the longest history of air conditioning usage.

[00:16:07] So, firstly, the population of hotter states, further south, has increased. Having air conditioning means the heat isn’t such an obstacle, and means that living in a hot place suddenly becomes more attractive, so long as you can control the indoor temperature, that is.

[00:16:28] The area of the US called The Sun Belt now has 30% of the US population vs. only 24% 100 years ago.

[00:16:38] Another unexpected consequence is an evening out, a flattening out of birth rates throughout the year. 

[00:16:48] In the United States, until the 1970s fewer babies were born in spring because the summer months were hot and sticky, and this meant that fewer babies were conceived when it was too hot inside. 

[00:17:03] As soon as Americans were able to regulate the indoor temperature, well, this changed, and the number of babies born in spring was similar to the rest of the year.

[00:17:16] Now, on to the ugly or negative consequences of air conditioning.

[00:17:23] It simply uses a colossal amount of electricity. 

[00:17:27] 20% of all electricity used within buildings globally is used to power air conditioners. And especially in countries with heavy fossil fuel usage, such as China, this electricity comes from burning fossil fuels, which in turn causes global temperatures to increase, causing an increased usage of electricity for air conditioning, and it’s a vicious cycle.

[00:17:54] What’s more, some of the chemicals that were used as coolants in air conditioners, one called Freon for example, have done terrible damage to the ozone layer. 

[00:18:06] Although production of Freon is now banned in the United States, it’s still in use by a majority of the air conditioner units, they don't actually have to get rid of it. 

[00:18:18] Air conditioners are getting more environmentally friendly, or rather less environmentally unfriendly, by using less damaging refrigerants and by being more energy efficient. 

[00:18:31] But, although the most efficient air conditioners end up costing less in the long term because they use less electricity, they are normally more expensive upfront, you have to pay more to buy one. 

[00:18:46] Especially in less wealthy countries, people are reluctant or unable to spend more money upfront, and also are not fully aware of the cost savings that can be had by buying more efficient air conditioners. 

[00:19:03] Therefore, even though the technology exists to make air conditioning units significantly more efficient, globally there are still a vast number of inefficient machines that are installed every year.

[00:19:18] What’s more, in the countries where the average temperature is above 25C, only 10% of people live with air conditioning. As these countries develop, more and more air conditioners will be sold, with the IEA, the International Energy Agency, predicting that up to 75% of people in the world’s hottest countries will have air conditioning. 

[00:19:44] And the result of this will be huge pressure on the energy networks.

[00:19:50] Now, is it all doom and gloom, is it all tragic? And what are some possible solutions to what some people have called a crisis in plain sight?

[00:20:03] Well, there are plenty of proposed solutions, both low and high tech.

[00:20:09] If you remember right at the start of the episode, when we talked about how the Egyptians and Romans cooled their houses, many energy experts have said that by making changes to how we design buildings in the first place we can reduce the demand for air conditioning. 

[00:20:27] There’s an idea called “passive cooling”, which really encompasses everything that uses non-electrical means to cool down air. It could mean planting trees, painting houses white to reflect the sun, more efficient shutters, and curtains and even air ducts, pipes that go through buildings allowing air to naturally circulate and cool buildings down.

[00:20:56] On a higher tech side, there are some interesting companies working on solutions that might remind you of the trick that the Dutch magician, Cornelius Drebbel, played on King James I. Remember that Drebbel only cooled a specific small piece of the room that he knew the king would walk through.

[00:21:18] So, there are companies that are working on personal air conditioning units, which aim to cool down small patches of air around an individual rather than entire rooms, and are thus significantly more efficient for certain use cases.

[00:21:36] In the future, it’s not unthinkable that access to cool air, or a “reasonable” indoor temperature, might be considered as an inalienable human right. 

[00:21:49] Whether this is delivered through lower tech “passive cooling” building design or higher tech products, it is certainly going to be an even greater concern in the years to come.

[00:22:01] In the meantime, sales of air conditioning units, based on the same principles and technology that was developed by Carrier back in 1903, continue to rise every single year, and are not predicted to slow down any time soon.

[00:22:17] Time will only tell the true cost of staying cool.

[00:22:24] OK then, that is it for today's episode on The History of Air Conditioning.

[00:22:31] I hope it's been an interesting one, that you've learnt something new, and that the next time you switch on your air conditioning, if indeed you are one of the billions of people who live in a house with air conditioning, then you’ll know a little bit more about the history of that marvellous box.

[00:22:48] As always, I would love to know what you thought of this episode.

[00:22:51] The place for that is our community forum, which is at community.leonardoenglish.com.

[00:22:57] You've been listening to English Learning for Curious Minds, by Leonardo English.

[00:23:02] I'm Alastair Budge, you stay safe, and I'll catch you in the next episode.


[END OF EPISODE]


Continue learning

Get immediate access to a more interesting way of improving your English
Become a member
Already a member? Login

[00:00:00] Hello, hello hello, and welcome to English Learning for Curious Minds, by Leonardo English. 

[00:00:11] The show where you can listen to fascinating stories, and learn weird and wonderful things about the world at the same time as improving your English.

[00:00:21] I'm Alastair Budge, and today we are going to be talking about Air Conditioning.

[00:00:27] Now, for many of you air conditioning might not seem like anything special. For billions of people around the world it is an effective way to regulate the temperature, keeping us cool and comfortable when we would otherwise be too hot.

[00:00:44] Indeed, for a large proportion of the developed world air conditioning has gone from a luxury to a necessity, and an American household is more likely to have air conditioning than a dishwasher or a dining room.

[00:01:00] But it most certainly hasn’t always been this way. 

[00:01:04] So, in today’s episode we are going to go on a tour of the rise of air conditioning, from how humans used to regulate the temperature to Dutch magicians playing tricks on British kings, from one of the founding fathers of the United States through to how the air conditioning unit became an integral part of our lives, changing our cities, countries, planet, and even reproductive habits.

[00:01:32] It is a fascinating story, so let’s get right into it.

[00:01:37] The desire to stay cool is, of course, nothing new. 

[00:01:43] The ancient Egyptians and Romans employed various techniques to cool down their buildings from the outside heat.

[00:01:52] Some people have even claimed that the first air conditioning unit was invented in ancient Egypt. The ancient Egyptians would hang wet reeds, wet plants, outside their windows, and when the air came into the house it would be cooled by the moisture on the plants. 

[00:02:13] The Romans understood that if they could bring cold water via aqueducts under their houses, then the temperature inside would fall, it would get colder. 

[00:02:26] And if we really stretch the meaning of the phrase “air conditioning”, then hand fans have been used since the dawn of time. People realised that they could move air by waving something and it would temporarily cool them down.

[00:02:45] The Chinese inventor Ding Huan went a step further in the second century and invented a rotating fan, similar to fans we might see today, although it was manually powered by unfortunate prisoners.

[00:03:01] But there is a limit for quite how much the temperature can be reduced by natural means, either by bringing cold water to a hot place or by fanning oneself.

[00:03:15] There was also, in much of the western world at least, a fear of trying to create artificial cold. 

[00:03:24] Cold was something that people didn’t really understand, and was thought to be something that only God could create. 

[00:03:34] People had no problems with artificially heating a room, by creating a fire, for example, but there was a fear about creating cold in an unnatural way.

[00:03:47] The author Tom Shachtman, in his 1999 book “Absolute Zero and the Conquest of Cold” suggests that this was because it was obvious how to create heat - you would simply start a fire, add wood to it, and ta-da, you could heat a room. But cold was more mysterious. 

[00:04:10] It was thought to have come from a mysterious place far to the north of Britain called Thule, and interfering with the creation of cold, at least in an artificial way, would be interfering with God.

[00:04:27] Some noblemen in Britain might have kept ice in ice cellars deep underground, and you might quite rightly joke that Britain was not exactly the country with the greatest need to lower the temperature, but even in warmer, equally developed countries there was a lack of understanding about, and even interest in, how temperatures could be lowered.

[00:04:54] One of the first records of an inside temperature being lowered by artificial methods actually comes in 1620, and involves a mysterious Dutch man called Cornelis Drebbel, who was a sort of magician, and the first King of a united England and Scotland, King James I.

[00:05:16] The Dutchman Drebbel had claimed that he was able to reduce the air temperature, and the king decided to put him to the test. He challenged him to do it in the Great Hall of Westminster Abbey, a room which would have been one of the largest in the country at the time and still is very large even by today’s standards.

[00:05:41] It was a hot summer’s day, and when King James entered the room he was surprised to find that it was indeed very cold. So cold, in fact, that he had to quickly leave because it was too cold for him.

[00:05:57] No records exist of exactly how Drebbel did it, but historians are fairly sure that he would have placed long trays where he knew the King would enter the room, filled them with cold water from the river Thames and ice, and then mixed it with salt and something called nitre or saltpeter, the mineral form of potassium nitrate.

[00:06:24] The addition of the nitre would have created a chemical reaction that reduced the temperature below freezing point, below zero, and cooled the air above the trays.

[00:06:38] Drebbel knew that cold air displaced hot air, it moved hot air, so the hot air would rise up, meaning that the cold air would stay relatively low, directly where he thought the king would pass.

[00:06:53] Just as Drebbel thought, the king entered the room and walked through the patch of cool air. The king would have assumed that the entire room had been cooled, whereas the reality was that just a small proportion of it would have been.

[00:07:11] Although this would have been a pretty cool trick, it wasn’t a sustainable long-term solution to reducing the temperature inside buildings.

[00:07:21] Scientists continued to experiment with chemical methods of reducing the temperature, and it was even a subject of great interest for one of the founding fathers of the United States, the polymath Benjamin Franklin, in the 1750s.

[00:07:38] His interest in the subject, reportedly, came from an experience that you may well have had. 

[00:07:45] One hot July day in Philadelphia, Benjamin Franklin, so the legend goes, was sitting at his desk writing. He was sweating a lot, and got up to change his sweaty, wet shirt.

[00:08:01] When he put on his fresh, dry shirt it felt hotter than the wet one he had taken off.

[00:08:09] He thought that perhaps this had something to do with the liquid evaporating, so he conducted a series of experiments. 

[00:08:19] He put various different materials on a thermometer and observed what happened when they evaporated.

[00:08:27] Sure enough, evaporation caused the temperature to reduce, and Franklin even observed that, "From this experiment one may see the possibility of freezing a man to death on a warm summer's day."

[00:08:28] The 19th century saw the arrival of more cooling technologies, including the creation of an ice making machine. Primitive versions of “air conditioning” could be created by pumping air over ice, but there wasn’t really a mass-market use case for this, and it was very expensive to do.

[00:08:28] Strange enough as it might seem to us now, there is simply not much evidence that people were shouting out for cooler temperatures inside. It was just accepted that on warm summer days you would be hot and slightly uncomfortable. 

[00:09:23] Houses would be cooled through natural means, by not allowing hot air to come in in the first place, and by using ventilation.

[00:09:34] The first air conditioning unit as we would know it only came in 1903, and was developed by an American man called Willis H. Carrier. He was asked by a printing company to create a machine that would regulate humidity in the building. 

[00:09:54] In the summer months the air inside the building was so humid that the paper would shrink, it would reduce in size. Of course, this was hugely disruptive to the operations of the printing business.

[00:10:10] Carrier created a machine that used a system of fans to blow over coils, small tubes in a ring, which would be filled with cold water.

[00:10:23] As the humid air moved over the cold coils, water would be removed from the air and the air temperature would fall, so when this air was blown out it was colder than before. What’s more, it also reduced the humidity.

[00:10:42] Bingo, Carrier had just invented the air conditioning system. Indeed, the majority of the 2 billion air conditioning units that exist globally today still work on a very similar principle - pushing air over something cold.

[00:11:00] The publishing company was very happy with Carrier, and he quickly patented his invention and created a company, a company that actually still exists today, is worth $50 billion and employs 56,000 people worldwide.

[00:11:18] But while you might think it was an immediate success, and Carrier was off to the races with his new invention, he wasn’t.

[00:11:28] The public took a lot of convincing that this was something that would actually benefit them. 

[00:11:35] The initial uses of air conditioning units were primarily in places like hospitals, and there was very limited personal use.

[00:11:45] The first contact that most Americans would have had with air conditioning was in movie theatres, in cinemas. 

[00:11:54] As you might imagine, small closed rooms with lots of sweaty people smoking for extended periods of time had pretty horrible, sticky air.

[00:12:07] Starting in the 1920s American cinemas started to use air conditioning systems to cool down their cinemas in the summer, making them significantly more pleasant places to be and attracting consumers who would have been put off going by how hot and sticky they were.

[00:12:28] The Great Depression and the Second World War put a dent in the adoption of air conditioners, but the post-war period in the United States was boom time for all sorts of consumer electronics, and air conditioners were no exception.

[00:12:46] This was helped by the price reducing dramatically. In 1932, when the first personal air conditioning units came on sale, they cost today’s equivalent of anywhere from $120,000 to $600,000. Obviously that put them out of the reach of everyone but the very richest - it was the equivalent of employing your own group of servants simply to follow you everywhere with a large fan.

[00:13:19] When Carrier first went on tour with his air conditioner units, it took a while for the American public to believe that they actually worked, and there are photos of him doing stunts like going to a fair and creating an igloo full of ice, which was cooled down of course by his air conditioning units.

[00:13:42] The marketing tricks worked, and more and more Americans decided to buy this latest must-have modern convenience. 

[00:13:51] By 1960, 12 percent of U.S. households had air conditioning. 20 years later, in 1980, it was 55 percent; now it’s 90 percent, only just behind Japan where 91% of houses have air conditioning.

[00:14:10] The rest of the world is following suit

[00:14:13] 60% of households in China now have AC, up from less than 8% in 1994.

[00:14:22] But the reality is that most households in hot countries, the households where the need to be cool is the greatest, don’t yet have an air conditioning unit.

[00:14:34] Fewer than 5% of households in India have air conditioning, 9% of households in Indonesia and 16% of households in Brazil have it.

[00:14:46] And by 2050 around 2/3 of the world’s households could have an air conditioner, according to the reports by The International Energy Agency.

[00:14:58] Now, let’s take a moment to think about the impact of this, the good, the bad, and the unexpected.

[00:15:06] So, the good. Purely on a personal human comfort level, it makes indoor life more manageable when it’s hot outside. 

[00:15:16] It is also hugely important in places like hospitals, where having a constant temperature is important for patient health.

[00:15:25] Being able to easily, quickly and cheaply reduce the temperature literally saves lives. Every year during heat waves people, normally older people, unnecessarily die at home, and air conditioning reduces the risk of this happening.

[00:15:43] So far so good.

[00:15:45] Before we get to “the bad”, let’s look at the unexpected, or perhaps indirect and not so immediately obvious.

[00:15:55] To understand this, it’s most helpful to look at the situation in the United States, since that is the country with the longest history of air conditioning usage.

[00:16:07] So, firstly, the population of hotter states, further south, has increased. Having air conditioning means the heat isn’t such an obstacle, and means that living in a hot place suddenly becomes more attractive, so long as you can control the indoor temperature, that is.

[00:16:28] The area of the US called The Sun Belt now has 30% of the US population vs. only 24% 100 years ago.

[00:16:38] Another unexpected consequence is an evening out, a flattening out of birth rates throughout the year. 

[00:16:48] In the United States, until the 1970s fewer babies were born in spring because the summer months were hot and sticky, and this meant that fewer babies were conceived when it was too hot inside. 

[00:17:03] As soon as Americans were able to regulate the indoor temperature, well, this changed, and the number of babies born in spring was similar to the rest of the year.

[00:17:16] Now, on to the ugly or negative consequences of air conditioning.

[00:17:23] It simply uses a colossal amount of electricity. 

[00:17:27] 20% of all electricity used within buildings globally is used to power air conditioners. And especially in countries with heavy fossil fuel usage, such as China, this electricity comes from burning fossil fuels, which in turn causes global temperatures to increase, causing an increased usage of electricity for air conditioning, and it’s a vicious cycle.

[00:17:54] What’s more, some of the chemicals that were used as coolants in air conditioners, one called Freon for example, have done terrible damage to the ozone layer. 

[00:18:06] Although production of Freon is now banned in the United States, it’s still in use by a majority of the air conditioner units, they don't actually have to get rid of it. 

[00:18:18] Air conditioners are getting more environmentally friendly, or rather less environmentally unfriendly, by using less damaging refrigerants and by being more energy efficient. 

[00:18:31] But, although the most efficient air conditioners end up costing less in the long term because they use less electricity, they are normally more expensive upfront, you have to pay more to buy one. 

[00:18:46] Especially in less wealthy countries, people are reluctant or unable to spend more money upfront, and also are not fully aware of the cost savings that can be had by buying more efficient air conditioners. 

[00:19:03] Therefore, even though the technology exists to make air conditioning units significantly more efficient, globally there are still a vast number of inefficient machines that are installed every year.

[00:19:18] What’s more, in the countries where the average temperature is above 25C, only 10% of people live with air conditioning. As these countries develop, more and more air conditioners will be sold, with the IEA, the International Energy Agency, predicting that up to 75% of people in the world’s hottest countries will have air conditioning. 

[00:19:44] And the result of this will be huge pressure on the energy networks.

[00:19:50] Now, is it all doom and gloom, is it all tragic? And what are some possible solutions to what some people have called a crisis in plain sight?

[00:20:03] Well, there are plenty of proposed solutions, both low and high tech.

[00:20:09] If you remember right at the start of the episode, when we talked about how the Egyptians and Romans cooled their houses, many energy experts have said that by making changes to how we design buildings in the first place we can reduce the demand for air conditioning. 

[00:20:27] There’s an idea called “passive cooling”, which really encompasses everything that uses non-electrical means to cool down air. It could mean planting trees, painting houses white to reflect the sun, more efficient shutters, and curtains and even air ducts, pipes that go through buildings allowing air to naturally circulate and cool buildings down.

[00:20:56] On a higher tech side, there are some interesting companies working on solutions that might remind you of the trick that the Dutch magician, Cornelius Drebbel, played on King James I. Remember that Drebbel only cooled a specific small piece of the room that he knew the king would walk through.

[00:21:18] So, there are companies that are working on personal air conditioning units, which aim to cool down small patches of air around an individual rather than entire rooms, and are thus significantly more efficient for certain use cases.

[00:21:36] In the future, it’s not unthinkable that access to cool air, or a “reasonable” indoor temperature, might be considered as an inalienable human right. 

[00:21:49] Whether this is delivered through lower tech “passive cooling” building design or higher tech products, it is certainly going to be an even greater concern in the years to come.

[00:22:01] In the meantime, sales of air conditioning units, based on the same principles and technology that was developed by Carrier back in 1903, continue to rise every single year, and are not predicted to slow down any time soon.

[00:22:17] Time will only tell the true cost of staying cool.

[00:22:24] OK then, that is it for today's episode on The History of Air Conditioning.

[00:22:31] I hope it's been an interesting one, that you've learnt something new, and that the next time you switch on your air conditioning, if indeed you are one of the billions of people who live in a house with air conditioning, then you’ll know a little bit more about the history of that marvellous box.

[00:22:48] As always, I would love to know what you thought of this episode.

[00:22:51] The place for that is our community forum, which is at community.leonardoenglish.com.

[00:22:57] You've been listening to English Learning for Curious Minds, by Leonardo English.

[00:23:02] I'm Alastair Budge, you stay safe, and I'll catch you in the next episode.


[END OF EPISODE]


[00:00:00] Hello, hello hello, and welcome to English Learning for Curious Minds, by Leonardo English. 

[00:00:11] The show where you can listen to fascinating stories, and learn weird and wonderful things about the world at the same time as improving your English.

[00:00:21] I'm Alastair Budge, and today we are going to be talking about Air Conditioning.

[00:00:27] Now, for many of you air conditioning might not seem like anything special. For billions of people around the world it is an effective way to regulate the temperature, keeping us cool and comfortable when we would otherwise be too hot.

[00:00:44] Indeed, for a large proportion of the developed world air conditioning has gone from a luxury to a necessity, and an American household is more likely to have air conditioning than a dishwasher or a dining room.

[00:01:00] But it most certainly hasn’t always been this way. 

[00:01:04] So, in today’s episode we are going to go on a tour of the rise of air conditioning, from how humans used to regulate the temperature to Dutch magicians playing tricks on British kings, from one of the founding fathers of the United States through to how the air conditioning unit became an integral part of our lives, changing our cities, countries, planet, and even reproductive habits.

[00:01:32] It is a fascinating story, so let’s get right into it.

[00:01:37] The desire to stay cool is, of course, nothing new. 

[00:01:43] The ancient Egyptians and Romans employed various techniques to cool down their buildings from the outside heat.

[00:01:52] Some people have even claimed that the first air conditioning unit was invented in ancient Egypt. The ancient Egyptians would hang wet reeds, wet plants, outside their windows, and when the air came into the house it would be cooled by the moisture on the plants. 

[00:02:13] The Romans understood that if they could bring cold water via aqueducts under their houses, then the temperature inside would fall, it would get colder. 

[00:02:26] And if we really stretch the meaning of the phrase “air conditioning”, then hand fans have been used since the dawn of time. People realised that they could move air by waving something and it would temporarily cool them down.

[00:02:45] The Chinese inventor Ding Huan went a step further in the second century and invented a rotating fan, similar to fans we might see today, although it was manually powered by unfortunate prisoners.

[00:03:01] But there is a limit for quite how much the temperature can be reduced by natural means, either by bringing cold water to a hot place or by fanning oneself.

[00:03:15] There was also, in much of the western world at least, a fear of trying to create artificial cold. 

[00:03:24] Cold was something that people didn’t really understand, and was thought to be something that only God could create. 

[00:03:34] People had no problems with artificially heating a room, by creating a fire, for example, but there was a fear about creating cold in an unnatural way.

[00:03:47] The author Tom Shachtman, in his 1999 book “Absolute Zero and the Conquest of Cold” suggests that this was because it was obvious how to create heat - you would simply start a fire, add wood to it, and ta-da, you could heat a room. But cold was more mysterious. 

[00:04:10] It was thought to have come from a mysterious place far to the north of Britain called Thule, and interfering with the creation of cold, at least in an artificial way, would be interfering with God.

[00:04:27] Some noblemen in Britain might have kept ice in ice cellars deep underground, and you might quite rightly joke that Britain was not exactly the country with the greatest need to lower the temperature, but even in warmer, equally developed countries there was a lack of understanding about, and even interest in, how temperatures could be lowered.

[00:04:54] One of the first records of an inside temperature being lowered by artificial methods actually comes in 1620, and involves a mysterious Dutch man called Cornelis Drebbel, who was a sort of magician, and the first King of a united England and Scotland, King James I.

[00:05:16] The Dutchman Drebbel had claimed that he was able to reduce the air temperature, and the king decided to put him to the test. He challenged him to do it in the Great Hall of Westminster Abbey, a room which would have been one of the largest in the country at the time and still is very large even by today’s standards.

[00:05:41] It was a hot summer’s day, and when King James entered the room he was surprised to find that it was indeed very cold. So cold, in fact, that he had to quickly leave because it was too cold for him.

[00:05:57] No records exist of exactly how Drebbel did it, but historians are fairly sure that he would have placed long trays where he knew the King would enter the room, filled them with cold water from the river Thames and ice, and then mixed it with salt and something called nitre or saltpeter, the mineral form of potassium nitrate.

[00:06:24] The addition of the nitre would have created a chemical reaction that reduced the temperature below freezing point, below zero, and cooled the air above the trays.

[00:06:38] Drebbel knew that cold air displaced hot air, it moved hot air, so the hot air would rise up, meaning that the cold air would stay relatively low, directly where he thought the king would pass.

[00:06:53] Just as Drebbel thought, the king entered the room and walked through the patch of cool air. The king would have assumed that the entire room had been cooled, whereas the reality was that just a small proportion of it would have been.

[00:07:11] Although this would have been a pretty cool trick, it wasn’t a sustainable long-term solution to reducing the temperature inside buildings.

[00:07:21] Scientists continued to experiment with chemical methods of reducing the temperature, and it was even a subject of great interest for one of the founding fathers of the United States, the polymath Benjamin Franklin, in the 1750s.

[00:07:38] His interest in the subject, reportedly, came from an experience that you may well have had. 

[00:07:45] One hot July day in Philadelphia, Benjamin Franklin, so the legend goes, was sitting at his desk writing. He was sweating a lot, and got up to change his sweaty, wet shirt.

[00:08:01] When he put on his fresh, dry shirt it felt hotter than the wet one he had taken off.

[00:08:09] He thought that perhaps this had something to do with the liquid evaporating, so he conducted a series of experiments. 

[00:08:19] He put various different materials on a thermometer and observed what happened when they evaporated.

[00:08:27] Sure enough, evaporation caused the temperature to reduce, and Franklin even observed that, "From this experiment one may see the possibility of freezing a man to death on a warm summer's day."

[00:08:28] The 19th century saw the arrival of more cooling technologies, including the creation of an ice making machine. Primitive versions of “air conditioning” could be created by pumping air over ice, but there wasn’t really a mass-market use case for this, and it was very expensive to do.

[00:08:28] Strange enough as it might seem to us now, there is simply not much evidence that people were shouting out for cooler temperatures inside. It was just accepted that on warm summer days you would be hot and slightly uncomfortable. 

[00:09:23] Houses would be cooled through natural means, by not allowing hot air to come in in the first place, and by using ventilation.

[00:09:34] The first air conditioning unit as we would know it only came in 1903, and was developed by an American man called Willis H. Carrier. He was asked by a printing company to create a machine that would regulate humidity in the building. 

[00:09:54] In the summer months the air inside the building was so humid that the paper would shrink, it would reduce in size. Of course, this was hugely disruptive to the operations of the printing business.

[00:10:10] Carrier created a machine that used a system of fans to blow over coils, small tubes in a ring, which would be filled with cold water.

[00:10:23] As the humid air moved over the cold coils, water would be removed from the air and the air temperature would fall, so when this air was blown out it was colder than before. What’s more, it also reduced the humidity.

[00:10:42] Bingo, Carrier had just invented the air conditioning system. Indeed, the majority of the 2 billion air conditioning units that exist globally today still work on a very similar principle - pushing air over something cold.

[00:11:00] The publishing company was very happy with Carrier, and he quickly patented his invention and created a company, a company that actually still exists today, is worth $50 billion and employs 56,000 people worldwide.

[00:11:18] But while you might think it was an immediate success, and Carrier was off to the races with his new invention, he wasn’t.

[00:11:28] The public took a lot of convincing that this was something that would actually benefit them. 

[00:11:35] The initial uses of air conditioning units were primarily in places like hospitals, and there was very limited personal use.

[00:11:45] The first contact that most Americans would have had with air conditioning was in movie theatres, in cinemas. 

[00:11:54] As you might imagine, small closed rooms with lots of sweaty people smoking for extended periods of time had pretty horrible, sticky air.

[00:12:07] Starting in the 1920s American cinemas started to use air conditioning systems to cool down their cinemas in the summer, making them significantly more pleasant places to be and attracting consumers who would have been put off going by how hot and sticky they were.

[00:12:28] The Great Depression and the Second World War put a dent in the adoption of air conditioners, but the post-war period in the United States was boom time for all sorts of consumer electronics, and air conditioners were no exception.

[00:12:46] This was helped by the price reducing dramatically. In 1932, when the first personal air conditioning units came on sale, they cost today’s equivalent of anywhere from $120,000 to $600,000. Obviously that put them out of the reach of everyone but the very richest - it was the equivalent of employing your own group of servants simply to follow you everywhere with a large fan.

[00:13:19] When Carrier first went on tour with his air conditioner units, it took a while for the American public to believe that they actually worked, and there are photos of him doing stunts like going to a fair and creating an igloo full of ice, which was cooled down of course by his air conditioning units.

[00:13:42] The marketing tricks worked, and more and more Americans decided to buy this latest must-have modern convenience. 

[00:13:51] By 1960, 12 percent of U.S. households had air conditioning. 20 years later, in 1980, it was 55 percent; now it’s 90 percent, only just behind Japan where 91% of houses have air conditioning.

[00:14:10] The rest of the world is following suit

[00:14:13] 60% of households in China now have AC, up from less than 8% in 1994.

[00:14:22] But the reality is that most households in hot countries, the households where the need to be cool is the greatest, don’t yet have an air conditioning unit.

[00:14:34] Fewer than 5% of households in India have air conditioning, 9% of households in Indonesia and 16% of households in Brazil have it.

[00:14:46] And by 2050 around 2/3 of the world’s households could have an air conditioner, according to the reports by The International Energy Agency.

[00:14:58] Now, let’s take a moment to think about the impact of this, the good, the bad, and the unexpected.

[00:15:06] So, the good. Purely on a personal human comfort level, it makes indoor life more manageable when it’s hot outside. 

[00:15:16] It is also hugely important in places like hospitals, where having a constant temperature is important for patient health.

[00:15:25] Being able to easily, quickly and cheaply reduce the temperature literally saves lives. Every year during heat waves people, normally older people, unnecessarily die at home, and air conditioning reduces the risk of this happening.

[00:15:43] So far so good.

[00:15:45] Before we get to “the bad”, let’s look at the unexpected, or perhaps indirect and not so immediately obvious.

[00:15:55] To understand this, it’s most helpful to look at the situation in the United States, since that is the country with the longest history of air conditioning usage.

[00:16:07] So, firstly, the population of hotter states, further south, has increased. Having air conditioning means the heat isn’t such an obstacle, and means that living in a hot place suddenly becomes more attractive, so long as you can control the indoor temperature, that is.

[00:16:28] The area of the US called The Sun Belt now has 30% of the US population vs. only 24% 100 years ago.

[00:16:38] Another unexpected consequence is an evening out, a flattening out of birth rates throughout the year. 

[00:16:48] In the United States, until the 1970s fewer babies were born in spring because the summer months were hot and sticky, and this meant that fewer babies were conceived when it was too hot inside. 

[00:17:03] As soon as Americans were able to regulate the indoor temperature, well, this changed, and the number of babies born in spring was similar to the rest of the year.

[00:17:16] Now, on to the ugly or negative consequences of air conditioning.

[00:17:23] It simply uses a colossal amount of electricity. 

[00:17:27] 20% of all electricity used within buildings globally is used to power air conditioners. And especially in countries with heavy fossil fuel usage, such as China, this electricity comes from burning fossil fuels, which in turn causes global temperatures to increase, causing an increased usage of electricity for air conditioning, and it’s a vicious cycle.

[00:17:54] What’s more, some of the chemicals that were used as coolants in air conditioners, one called Freon for example, have done terrible damage to the ozone layer. 

[00:18:06] Although production of Freon is now banned in the United States, it’s still in use by a majority of the air conditioner units, they don't actually have to get rid of it. 

[00:18:18] Air conditioners are getting more environmentally friendly, or rather less environmentally unfriendly, by using less damaging refrigerants and by being more energy efficient. 

[00:18:31] But, although the most efficient air conditioners end up costing less in the long term because they use less electricity, they are normally more expensive upfront, you have to pay more to buy one. 

[00:18:46] Especially in less wealthy countries, people are reluctant or unable to spend more money upfront, and also are not fully aware of the cost savings that can be had by buying more efficient air conditioners. 

[00:19:03] Therefore, even though the technology exists to make air conditioning units significantly more efficient, globally there are still a vast number of inefficient machines that are installed every year.

[00:19:18] What’s more, in the countries where the average temperature is above 25C, only 10% of people live with air conditioning. As these countries develop, more and more air conditioners will be sold, with the IEA, the International Energy Agency, predicting that up to 75% of people in the world’s hottest countries will have air conditioning. 

[00:19:44] And the result of this will be huge pressure on the energy networks.

[00:19:50] Now, is it all doom and gloom, is it all tragic? And what are some possible solutions to what some people have called a crisis in plain sight?

[00:20:03] Well, there are plenty of proposed solutions, both low and high tech.

[00:20:09] If you remember right at the start of the episode, when we talked about how the Egyptians and Romans cooled their houses, many energy experts have said that by making changes to how we design buildings in the first place we can reduce the demand for air conditioning. 

[00:20:27] There’s an idea called “passive cooling”, which really encompasses everything that uses non-electrical means to cool down air. It could mean planting trees, painting houses white to reflect the sun, more efficient shutters, and curtains and even air ducts, pipes that go through buildings allowing air to naturally circulate and cool buildings down.

[00:20:56] On a higher tech side, there are some interesting companies working on solutions that might remind you of the trick that the Dutch magician, Cornelius Drebbel, played on King James I. Remember that Drebbel only cooled a specific small piece of the room that he knew the king would walk through.

[00:21:18] So, there are companies that are working on personal air conditioning units, which aim to cool down small patches of air around an individual rather than entire rooms, and are thus significantly more efficient for certain use cases.

[00:21:36] In the future, it’s not unthinkable that access to cool air, or a “reasonable” indoor temperature, might be considered as an inalienable human right. 

[00:21:49] Whether this is delivered through lower tech “passive cooling” building design or higher tech products, it is certainly going to be an even greater concern in the years to come.

[00:22:01] In the meantime, sales of air conditioning units, based on the same principles and technology that was developed by Carrier back in 1903, continue to rise every single year, and are not predicted to slow down any time soon.

[00:22:17] Time will only tell the true cost of staying cool.

[00:22:24] OK then, that is it for today's episode on The History of Air Conditioning.

[00:22:31] I hope it's been an interesting one, that you've learnt something new, and that the next time you switch on your air conditioning, if indeed you are one of the billions of people who live in a house with air conditioning, then you’ll know a little bit more about the history of that marvellous box.

[00:22:48] As always, I would love to know what you thought of this episode.

[00:22:51] The place for that is our community forum, which is at community.leonardoenglish.com.

[00:22:57] You've been listening to English Learning for Curious Minds, by Leonardo English.

[00:23:02] I'm Alastair Budge, you stay safe, and I'll catch you in the next episode.


[END OF EPISODE]