SYMHC Classics: Air Conditioning

This 2018 episode covers the many ways people have dealt with heat and humidity in history. As mechanical cooling became more ubiquitous, some of the cultural practices for keeping cool were made obsolete.

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Episode Transcript

Speaker 1 (00:02):
Happy Saturday. Not too long ago, we had an episode
on Augustine Daily and we talked about the installation of
air conditioning at his Fifth Avenue Theater in New York.
Not long after that episode came out, we got an
email from listener Charlotte asking if we had ever done
an episode on the history of air conditioning, and I thought, hey,

(00:23):
I meant to pull that out as a Saturday classic
to run after the Augustine Daily episode, but I forgot
so here it is now weeks later, Thanks Charlotte. This
episode originally came out on August twenty ninth, twenty eighteen.
Welcome to Stuff You Missed in History Class, a production

(00:43):
of iHeartRadio. Hello, and welcome to the podcast. I'm Tracy V.
Wilson and I'm Holly Frye. It's August, although by the
time this podcast comes out I could possibly be September.
Not quite sure when this one's gonna drop yet. And also,

(01:04):
it's hot. That's what August means usually for us, at least,
yeah for us for sure. I started working on this
episode on one of those days when I woke up
and it was already eighty two degrees inside my apartment.
It is eighty six degrees in my little studio right now,
I am sitting with a cold pack draped over my chair.
So I decided we should talk about the history of

(01:26):
air conditioning. And sorry to our Southern Hemisphere friends who
are always getting the episodes in which I'm complaining that
it's hot, and so We're going to talk about ice
or air conditioning or whatever. When it's winter there. I
could go there and complain about winter while you're here
and complain about hot because I love the heat, but

(01:48):
that cold is not for me. So about a year ago,
we did an episode on Frederick Tudor, who cut ice
out of ponds in Massachusetts in winter and then turn
that into a globally traded commodity. In that episode, we
talked about some of the ways that people had been
making ice and refrigerating things in warmer parts of the

(02:08):
world before the establishment of the ice trade and the
development of mechanical refrigeration. Things like people in the Indian
subcontinent using earthenware vessels as evaporative coolers to make kind
of a semi frozen slush, or using saltpeter infused water
to chill bottles of beverages. Similarly, people all over the
world had figured out ways to keep themselves at least

(02:31):
relatively cool for millennia before the invention of air conditioning,
and a lot of these methods are still in use
in one way or another today. The most obvious starting
point is the fan. People have probably fanned themselves with
their hands or with relatively flat objects for about as
long as people have existed, but in terms of objects
created specifically as fans, we know that goes back at

(02:55):
least five thousand years. We have examples of hand fans
from numerous ancient civilizations all over the world. The earliest
fans were fixed or rigid, and made of all kinds
of feathers, fronds, textiles, and other materials. The first folding
fans were probably developed in either Japan or China. There

(03:15):
are examples from both that are about the same age,
and both nations have their own lore about the development
of the folding fan. Of course, fans themselves have their
own history, with all kinds of mythology and symbolism and
etiquette and art and culture woven in, and a lot
of culture's fans have also had religious or ceremonial uses

(03:35):
as well. And that's on top of all the variation
in the materials that fans have been made of and
how they've been designed and constructed. We probably, if we
felt inclined, could do a whole episode just on fans.
Only if we talk about Star Trek and the fan dance,
then I'm in a lot of the earliest personal cooling

(03:57):
methods were built around the fan, people either fanning themselves
or having a servant or an enslaved person do it
for them. In places that were both hot and dry,
people used fans to force air through dampened screens or mats,
which would both humidify the air and cool the air
as water evaporated. In places where it was hot and damp,

(04:18):
people were more likely to use fans to move air
over ice, although that still made the room even more humid,
and depending on where that ice came from, it might
also make the room smell like gross pond water. After
President James Garfield was shot in eighteen eighty one, his
doctors used a variation on this fan and ice method
to try to keep him cool, and that used almost

(04:40):
five hundred pounds of ice per day. Leonardo da Vinciti
developed a water powered fan in about fifteen hundred, and
mechanically driven fans powered by things like hand cranks were
developed about the same time. The first electric fan was
developed by Crocker and Curtis Electric Motor Company in eighteen
eighty two. That in eighteen eighty four, William Whiteley developed

(05:03):
the all Weather Eye, which was a fan that attached
to the axle of a carriage, so when the carriage
was moving, the fan turned and it forced air over
a block of ice that was mounted under the passenger area,
sort of air conditioning the inside of the carriage. That's
pretty ingenious. There are also all kinds of architectural features

(05:23):
all over the world intended to keep people cooler. Before
industrialization and the creation of air conditioning, most people lived
in buildings that were adapted to where they lived. They
used local materials and building techniques which were suited to
the needs of the climate and the landscape. The whole
idea is summed up as vernacular architecture. Vernacular architecture is

(05:45):
absolutely full of ways to deal with heat and humidity,
and there are so many that we cannot possibly name
them all, just like we cannot possibly name every variation
on the fan. But here are some examples. People on
coasts oriented their homes to catch this sea breeze through
the windows. Porches gave people an outdoor, semi sheltered place

(06:05):
to go when the house got too hot, and sleeping
porches had bunks or hammocks already there for when it
was just too hot to possibly go to sleep in
the house. Thick walls, high ceilings, and large windows have
insulated buildings while also allowing air circulation. Shady courtyards and
fountains of offered respite from the heat, and in places

(06:26):
where it's hot in the day and cool at night,
thick walls made from mud or adobe absorb heat during
the day and to keep the inside cooler, and then
release it at night to keep the inside warmer. Then,
of course there's just planting trees to shade the buildings
from the sun. In the southeastern United States, one common
design was the dog trot house. This was a house

(06:47):
with two halves separated by a roofed breezeway in between,
which usually also connected a front and back porch. Usually
the kitchen was on one side of the dog trot
while the sleeping area was on the other, so you
weren't heating up your bedroom while you were cooking your food.
Dog trot houses were often built upon bricks or stones
rather than resting on a foundation or the ground, and

(07:09):
that allowed air to circulate under the house as well.
And sometimes these are also called possum trot houses. And
the same basic design is still used in some places today.
My sister in law lives in a house just like this. Yeah,
there are also, I mean there are historic ones that
still stand in newly built houses that are still following
that same basic design. I remember when I was in

(07:30):
college there was one at the botanical gardens next door
to the campus where we like to go sit around
and read. Step wells are a way of dealing with
the heat in very arid countries, especially on the Indian subcontinent.
This is a pool of water very very deep underground
which people would reach down an incredibly long spiral or

(07:50):
zigzag staircase. These pools had to be that deep underground
because that's how far down you had to go to
get to the water table. They were used as a
water but then also having such a deep, dark underground
shaft gave people a place to retreat out of the heat.
Sometimes stepwells were designed to serve as very large gathering
places with intricate stairways and terraces, basically lots of places

(08:14):
for people to go down there and chill out. A
lot of these stepwells fell into disuse as human activity
lowered the water table, either gradually filling with trash or
being taken over by animals. The British Empire also destroyed
a lot of them under the idea that they were unsanitary,
and this was kind of ironic since it was extremely
fashionable for British people to complain about how miserable the

(08:37):
heat was in colonial India. Today, though, some stepwells are
being restored and reopened as water sources, and the same
principle has been used to design modern buildings that require
less energy to cool. Wind catchers were common in Persian
architecture starting thousands of years ago, and a lot of
them are still standing and still working today. This is

(08:58):
essentially a window tower that's built to take advantage of
the prevailing winds, so exactly how the tower is designed,
how many windows it has, and which direction it faces
depends on where it's being built. When the wind blows
through a windcatcher, it draws hot air up out of
the house. Sometimes there's also a reservoir of water or
a very deep well inside the house, so as the

(09:20):
hot air moves out, moist, cooler air is pulled up
from below. A similar design was also part of ancient
Egyptian architecture. So vernacular architecture is just full of things
like this, and people living in hot places have also
adapted their behavior, like the siesta during the hottest part
of the day. But as areas have adopted air conditioning,

(09:42):
these traditional elements have tended to disappear as people instead
design buildings that are going to be mechanically cooled. And
we're going to start talking about that in some detail
after we first pause for a little sponsor break. Modern

(10:04):
air conditioning was developed in the United States, and the
United States has adopted it much faster than the rest
of the world, so the next stretch of this show
is going to be pretty US centric. The first person
in the United States to write down some thoughts for
creating a large scale way to cool places was John
Gory in eighteen forty two. He wrote about wanting to

(10:25):
use mechanical condensation to quote counteract the evils of high
temperature and improve the condition of our cities. He speculated
about a massive city that could use one machine to
cool off the entire place, as well as to cool
individual buildings. It's not clear whether he ever made a
working prototype of this air conditioner he had in mind,

(10:47):
but he did create a refrigerator that could make ice.
He had this working at the US Marine Hospital in Apalachicola, Florida,
in eighteen forty four, and he patented it in eighteen
fifty one. That ice was put to use in conjunction
with fans to try to keep patients with malaria and
yellow fever cool. By eighteen eighty, people were using fans

(11:08):
and ice together to try to cool buildings on a
much larger scale. That year, New York's Madison Square Theater
was using four tons of ice per day to try
to cool the theater in the summer. Before trying that
it would pretty much just not had shows in the summer.
There's some overlap in the development of refrigeration and air conditioning,
and in the late eighteen eighties people were also using

(11:31):
refrigeration to try to cool whole rooms. Pipes were used
to carry a refrigerant from a central station out to customers,
and this central station refrigeration was mainly used to cool
whole rooms for things like meat packing and cold storage.
A few businesses did try to put central station refrigeration
to use basically as air conditioning for people's comfort, though.

(11:54):
In eighteen ninety one, a restaurant called Ice Palace opened
in Saint Louis, Missouri that used central station refrigeration to
keep the whole building cool, and it also decorated the
place with lots of pictures of wintry scenes. Over the
next couple of decades, several people started designing the systems
that evolved into modern air conditioning. Alfred Wolf created cooling

(12:16):
systems for a number of buildings in the late nineteenth
and early twentieth centuries. In eighteen eighty nine, he created
a ventilation system for Carnegie Hall or Carnegie if you
liked that pronunciation, but most people except Carnegie Hall as
the pronunciation on that one. These included racks for blocks
of ice, and that same year he used chilling coils

(12:36):
to cool the air in a dissecting room at Cornell
Medical College, which seems like an excellent venue for air conditioning.
In nineteen oh two, he created a fan driven system
for the New York stock Exchange that cost one hundred
and thirty thousand dollars, and it could heat and cool
the building. In cold weather, steam boilers added heat and humidity,
and in hot weather, the air moved over coils that

(12:59):
were filled with a cooling brine to cool and dehumidify.
At about the same time, engineer Stuart Kramer was working
in textile mills in the South, especially in the winter.
That air in these mills would become very dry, which
was a problem. Cotton thread is a lot more brittle
and likely to snap when it's too dry. Wool is

(13:19):
a lot easier to work when it's properly moist. Plus
static electricity when working with a bunch of textiles in
too dry air, could be just unbearable. Kramer developed systems
that combined ventilation with humidification. They basically circulated the air
while also releasing a very fine mist of water. The
word that he coined for this combination of temperature and

(13:41):
humidity control was air conditioning. Kramer was awarded a patent
for his air conditioning system in nineteen oh six. Concurrently
with Wolf and Kramer, Willis Carrier was working at Buffalo
Forge Company and the company made things like blowers and bellows,
and he had been made head of its new ex
experimental engineering department. Those three men that we've just talked about,

(14:04):
his is probably the name that at least rings a
bell because Carrier is still associated with air conditioning. We
just got a new air conditioner installed and it is
a Carrier unit. So. Second, Wilhelm's Lithographic and Publishing Company
in Brooklyn, New York, was one of Buffalo Forged Company's clients,
and they were having a problem with humidity. Variations in

(14:27):
the humidity affected the paper that was running through their
printing presses. Sometimes this would cause the ink to bleed
or to smear, or for the paper to visibly warp.
But a bigger problem was that they were printing in color.
Colored inks went onto the paper one layer at the time.
Even a slight difference in humidity affected the paper enough

(14:48):
that the colors would be out of register. Those layers
wouldn't line up correctly. It would not look like a
cleanly printed color document. It would look like overlapping out
of the lines, messed up color. I'm thinking about the
various episodes we have done about artists and their work
getting printed cheaply, and I'm betting probably these problems were

(15:09):
part of how they ended up such a mess. So
Carrier developed a system that moved air over a series
of coils that were cooled with compressed ammonia. Moisture condensed
out of the air and onto the coils, drying it out,
which also had the side effect of cooling the air off.
He ultimately developed a cooling, dehumidification, and air circulation system

(15:31):
that maintained a temperature of seventy degrees fahrenheit in winter
or eighty degrees in summer, and a relative humidity that
was a consistent fifty five percent. This was Carrier's first
attempt at endoor climate control, and he went on to
be awarded numerous patents within the field. The first one
was issued in nineteen oh six that was US Patent

(15:51):
number eighth eight eight nine seven apparatus or treading Air.
It described a process for forcing air through a spray
of water and then through a set of baffles to
remove any kind of pollutants or impurities, before then heating
or cooling it and adding or removing humidity. In late
nineteen oh seven, Buffalo Forge Company established Carrier Air Conditioning

(16:13):
Company of America as a subsidy. Willis Carrier was vice
president and chief engineer. Among the first clients were flour
mills and Jellette. Too much humidity was causing the razor
blades to rust, and in nineteen eleven Carrier gave an
address on his rational psychometric formulae at the American Society
of Mechanical Engineers. This was also published in the Society's journal,

(16:36):
and the printed version started quote. A specialized engineering field
has recently developed, technically known as air conditioning or the
artificial regulation of atmospheric moisture. The application of this new
art to many varied industries has been demonstrated to be
of greatest economic importance. When applied to the blast furnace,

(16:57):
that has increased the net profit in the production of
pig iron from fifty cents to seventy cents per ton,
and in the textile mill it has increased the output
from five to fifteen percent, at the same time greatly
improving the quality and the hygienic conditions surrounding the operative.
And many other industries such as lithographing, the manufacture of

(17:18):
candy bread, high explosives and photographic films, and the drying
and preparing of delicate hygroscopic materials such as macaroni and tobacco.
The question of humidity is equally important. While air conditioning
has never been properly applied to coal mines, the author
is convinced that if this were made compulsory, the greater

(17:40):
number of mine explosions would be prevented. The paper goes
on to detail all kinds of formulas about temperature, humidity,
and dew point, how they're interrelated, how they can be adjusted,
and what the effect of those adjustments would be. So
that introduction to the paper and the paper itself highlight
a couple of things. One is that initially air conditioning

(18:04):
had a slightly different meaning than it does today. Today
we most associate air conditioning with keeping things cool and
not too humid. Another is that, almost without exception, it
was not about the workers' comfort. It was about the
products they were making and the temperature and humidity needs
of the materials and equipment they were working with, in

(18:25):
order to make them more productive and to make the
business more profitable. You can be hot and sweaty, but
the paper cannot correct. We're going to get into how
air conditioning finally became a household commodity after we first
paused for a little sponsor break in the early nineteen hundreds.

(18:51):
The general public didn't get to experience much air conditioning
in the United States unless it was something that was
being employed at their work to make their work were profitable.
The Saint Louis World's Fair used mechanical cooling at the
Missouri State Building in nineteen oh four. Roughly twenty million
people attended the fair, and for a lot of them
this was the first ever experience they had with air conditioning.

(19:14):
Home air conditioning was still way out of reach. The
first home air conditioner was installed in nineteen fourteen at
the Charles Gates Mansion in Minneapolis, and it's not clear
whether or not that air conditioner was ever actually used
because no one was living in the mansion at the time.
That same year, Buffalo Forge Company decided to pull out
of the air conditioning business. Willis Carrier and some of

(19:36):
his colleagues founded Carrier Engineering Corporation the following year, with
Carrier as its president. Still at this point, air conditioning
was mainly focused on industry and not comfort, and the
availability of air conditioning meant that factories were being opened
in places where the climate had not been very conducive
to it before that. Industrial systems did sometimes have a

(19:57):
side effect of making things more comfortable for workers, though.
For example, the use of air conditioning in tobacco processing
kept the tobacco leaves at the right humidity level, but
it also really cut down on the amount of dust
that the workers were subjected to. There are, also, of course,
other cases where it was the opposite, where this new
air conditioning system would make it feel to employees like

(20:19):
it was cold and damp, and they would want to
open the windows, and if they opened the windows, that
would ruin the entire point of having had this air
conditioning in the first place. It was in the nineteen
twenties that people started experiencing air conditioning that was specifically
installed to make them more comfortable while also still being
all about profitability. Because this was at movie theaters. There

(20:41):
had been theater cooling systems that combined ice blocks and
fans before this, but they often weren't all that effective.
They might wind up with some parts of the theater
being cold and damp while others were hot and damp.
Carrier Engineering Corporation installed the first modern air conditioning system
at a movie theater, Metropolitan Theater in Los Angeles in

(21:02):
nineteen twenty two, and this was the start of three
huge trends. Number one, air conditioned movie theaters. Number two
movie theaters heavily advertising their air conditioning, and number three
big movies coming out in the summer when everybody would
be going to the movies to get out of the heat.
By the start of World War Two, most of the

(21:23):
movie theaters in the southern United States had air conditioning,
and the US isn't the only place where movie theaters
were the first public buildings to be air conditioned. The
first public building to be air conditioned in Hong Kong
was King Cinema that happened in nineteen thirty one. After
movie theaters, the next public buildings to be air conditioned
in the United States were mostly large department stores, especially

(21:46):
in the South. Smaller stores followed, and then came office buildings,
with the first air conditioned offices often being banks. The
United States government started air conditioning some of its buildings
in the late nineteen twenties. The House of Representatives chamber
was air conditioned in nineteen twenty eight, and then the
Senate in nineteen twenty nine, and then the White House

(22:06):
and Executive Building in nineteen thirty. The Supreme Court was
air conditioned in nineteen thirty one. There had been some
debate about whether these systems should be installed, Even though Washington,
DC summers are famously punishing in terms of the heat
and humidity. There were worries that people would see legislators
and Supreme Court justices as weak if they were going

(22:27):
to work in comfortable air conditioned buildings. Over these same years,
Carrier and other engineers were continuing to refine air conditioning technology.
Has included more efficient compressors for the refrigerant and refrigerants
themselves that were safer to use. That compressed ammonia that
was being used in the earliest air conditioners was extremely toxic.

(22:50):
What breathing ammonia air isn't good for me? Even so,
by the nineteen twenties, home air conditioning was still pretty rare,
unless a person was perhaps so healthy that they could
afford to install one at their unoccupied mansion in Minnesota.
But that started to change as corporations started to develop
more compact and affordable models. Brigid Air debuted a room

(23:12):
cooler in nineteen twenty nine. In nineteen thirty one, HH
Schultz and JQ. Sherman launched an early version of the
window air conditioner that was too expensive to actually be workable.
The Thorn room air conditioner came out in nineteen thirty two,
and most of today's window air conditioners still look a
lot like it. Yeah, the window air conditioning technology has

(23:35):
not changed all that much since this happened. Hotels had
started installing air conditioning not long after movie theaters did,
but at first it was only in the lobbies and
the public spaces. The first hotel with air conditioned guest
rooms was the Detroit Statler in nineteen thirty four. Even
though window air conditioners were starting to become a lot

(23:57):
more affordable, the Great Depression took a toll on the
whole industry. One exception was in the American Southwest, which
was also struck by the dust bowl. At about the
same time, people who could find the money to do
so installed air conditioners to try to keep the relentless
dust out of their homes. In nineteen thirty nine, the
Carrier Company went to the New York World's Fair with

(24:19):
its Igloo of Tomorrow which both demonstrated and educated people
about air conditioning. That same year, Packered debuted the first
air conditioned car, but that was pretty slow to be adopted.
Only ten percent of cars sold in the United States
had air conditioning in nineteen sixty six, but by two
thousand it was ninety eight percent. Also in the nineteen thirties,

(24:41):
swamp coolers started to be manufactured to cool the air
in dry environments. Unlike most of the systems we've been
talking about, which used coils filled with some kind of
refrigerant to cool and dehumidify the air, swamp coolers cool
the air by adding moisture. Greyhound started air conditioning its
buses in night eighteen forty, and in nineteen forty two,

(25:01):
power plants in the United States started implementing summer peaking
to handle the increased electricity demand caused by all this
air conditioning. The first really affordable window units hit the
market in nineteen fifty one, which put air conditioning on
the way to becoming almost ubiquitous in the United States.
Even though John Gory's first attempt at creating a cooling

(25:22):
system was all about patients in a hospital, hospitals were
slow to adopt air conditioning. By nineteen sixty two, only
fifteen percent of hospital patient rooms in the United States
were air conditioned. That same year, a Federal Housing Administration
official was quoted as saying, quote, within a few years,
any house that is not air conditioned will probably be obsolescent.

(25:44):
I couldn't find data about public schools, but just as
a side note, I was in public school in North
Carolina from nineteen eighty to nineteen ninety three. I was
almost never in an air conditioned classroom. Nor was my
college dorm air conditioned. I'm a few years ahead of you,
but by that point I was in Florida and everything
was air conditioned. So yeah, So the only classrooms I

(26:07):
remember being air conditioned were in one case, being in
a newly constructed part of the school that was like
brand new. We also had these things that were called
portable classroom units. Oh yeah, really trailers. The trailers were
air conditioned most of the time with like a little
window unit, and that was really it. So we had

(26:28):
this whole system of if it was going to be
too hot for it to be safe in the classroom,
we had an hour early dismissal. Huh. Fascinating. Yeah, so, uh,
that's the story of how hot it was. There would
usually be an oscillating fan mounted up on the wall,
and just the kids in the classroom seats would just
sort of sway back and forth trying to catch the

(26:49):
air from the oscillating fan for as long as possible. Meanwhile,
I was like the weirdy kid, like, can I stand outside?
It's cold in here. Central air conditioning debuted in the
nineteen seventies. That was also in the middle of an
energy crisis. This prompted the US federal government to put
together its first federal energy efficiency standard for air conditioning.

(27:13):
So to be clear, when central air conditioning debuted, there
were plenty of places that were having the whole building
air conditioned, but this was like a custom designed system
most of the time, rather than having a model for
central air conditioning that could be applied to a lot
of different homes. Like we said earlier, air conditioning was
adopted much faster in the United States than in the

(27:34):
rest of the world. In nineteen eighty, half of the
world's air conditioning was installed in the United States. This
means that the United States has also been using a
lot more electricity on air conditioning than the rest of
the world has, even as other nations have started adopting
air conditioning a lot more rapidly in more recent years.
In twenty fifteen, the United States was using more electricity

(27:57):
for air conditioning than the entire rest of the world
war and was using more electricity just for ac than
the entire continent of Africa was using for any purpose
at all. According to the Energy Information Administration's Residential Energy
Consumption Survey that was released in twenty eleven, eighty seven
percent of households in the United States have an air

(28:18):
conditioner or central air. By comparison, eleven percent of households
in Brazil and two percent of households in India had
air conditioning at the same time. However, the popularity of
air conditioning is spreading, and it's already approached the saturation
point in some other countries, including China, South Korea, and Japan.
In twenty ten, fifty million air conditioning units were sold

(28:40):
in China alone. This has, of course led to environmental
concerns as a global adoption of air conditioning starts to
align with what already happened in the United States. According
to some estimates, electricity demand for air conditioning could increase
tenfold by the air twenty fifty. That is on top
of concerns about refrigerator and their effects on the environment.

(29:02):
Listeners of a certain age will probably remember concerns about
the chlorofluorocarbons like free on, which were banned in the
late nineteen eighties because of their role in depleting the
planet's ozone layer. And then there's the fact that air
conditioners pump hot air out and cool air in, so
the air just gets hotter around any building where air
conditioning is used, which then requires more air conditioning. So

(29:24):
in some places architects and designers are looking at ways
to incorporate some of those elements of vernacular architecture so
that it doesn't take quite so much electricity and mechanical
air conditioning to cool the place off. The existence of
air conditioning has also had a huge impact on so
many things, including architecture, human behavior, and demographics, everything from

(29:48):
fewer premature deaths during heat waves to the existence of
computers since their components can't really be manufactured without temperature
and dust control. The advent of air conditioning has been
credited with people retiring to the South, particularly to Florida.
It's also been credited with leading to more industrialization and
urbanizing parts of the American South. There is still some

(30:11):
debate about correlation versus causation, but in general, air conditioning
has been cited as one element in a massive Southern
population boom in the last fifty years. As one example
that ties all of this together, during the post World
War II Baby boom, huge numbers of white, middle class
Americans were buying houses in the suburbs. Many of those

(30:33):
newly designed houses were built to be cooled through air conditioning.
Particularly popular in the region of the southern US that's
known as the Sun Belt was the ranch house, one
story flat, often with a large picture window in the
living room but small, narrow windows elsewhere. It had none
of the vernacular design elements that we talked about earlier
meant to help a building stay cool because it was

(30:55):
meant to be cooled with AC. And then there's another
trend that wraps back how air conditioning really started out
to help industries. According to research by economist William Nordhaus,
around the world, as a general trend, the hotter the
average temperature, the less productive people are. In the past,
this trend has been used to prop up racist stereotypes

(31:18):
about people from the hottest parts of the world. But
really there's just a lot of data that being hot
makes it harder to be productive. Just as one example,
this summer that we're recording this podcast, the Harvard THH.
Chan School of Public Health published a study about how
students who lived in non air conditioned buildings in Boston

(31:40):
performed more poorly on cognitive tests than their peers who
had air conditioning. So, at least in theory, air conditioning
or some method of cooling makes countries with a really
hot climate more productive than they could be without it.
So it's still about productivity and profitability as much as
it's about people's coming. The two are kind of inseparable. Really. Yeah,

(32:04):
it's part of how it all works. Thanks so much
for joining us on this Saturday. Since this episode is
out of the archive, if you heard an email address
or a Facebook RL or something similar over the course
of the show, that could be obsolete. Now. Our current
email address is History Podcast at iHeartRadio dot com. Our

(32:29):
old house stuffworks email address no longer works. You can
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(32:53):
iHeartRadio app, Apple podcasts, or wherever you listen to your
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