How air conditioning changed the world

 By Nicholas Newman

Keeping cool in the heat of summer has been a challenge since ancient times. In fact, air conditioning in buildings is not a new idea…

There are records of ancient Romans making efforts to keep themselves cool in the heat of summer. In fact, the third century Roman Emperor Elagabalus sent slaves to collect snow from nearby mountains, to spread about his gardens. He then had his servants use fans to make a cooling wind.
Other passive cooling methods used over the centuries have included using bright colors on walls and roofs to reflect the heat and making use of fountains and pools. In fact, many of the world’s historic houses like the Alhambra Palace in Granada, Villa d’Este near Rome and the village of Santorini in Greece are examples of passive air conditioning technologies in use.

Villa d'Este, Tivoli (M.Maselli, Flickr)

The modern birth of air conditioning

However, until the start of the 20th century, there was little progress in developing new air-conditioning technologies. But, 1902, was the birth of artificial cooling, and what we call air conditioning today. This innovation is due to work of a young engineer called Willis Carrier, then working at a heating company named Buffalo Forge. Willis Carrier was approached by now defunct New York-based printing company Sackett & Wilhelms. It was having problems in its printing process, caused by fluctuating levels of humidity. When printing a picture in color, this required the same paper to be printed four times—in cyan ink, magenta, yellow, and black. If the humidity changed between print runs, the paper would slightly expand or contract, causing a poor print finish.

Willis Carrier designed the first modern air-conditioning system (

Willis Carrier came up with the solution. His innovative idea to control humidity levels was what we call conditioning today. It involved circulating air over coils chilled by compressed ammonia, which maintained the humidity at a constant 55 percent.

Soon this discovery was adopted by a range of industries including textiles, flour mills, and the Gillette Corporation, to reduce the moisture razor blade production. However, it was not until 1906 that Willis Carrier saw the opportunity to exploit his invention in public buildings such as theaters and cinemas. In fact, everything from the production of baked goods to wartime supplies was made possible by air conditioning. In the 1920s and 1930s, the arrival of air conditioning in cinemas aided the popularity of going to the movies, in order to escape the summer heat. Because of this invention to control air temperatures and humidity, it enabled the spread of shopping malls, transatlantic flights, computers and servers that support the Internet.

The market for air conditioning

Today there seems an ever-growing hunger in the world to keep cool using air-conditioning units and systems. The market is expected to generate over $68.93 billion value by 2022 at an estimated compound annual growth rate of 4.34% from 2016 to 2022. This could mean that 137.8 million units could have been sold by 2020. The main market for air conditioning is the Asia Pacific region with China leading, though there has been growth in other developing regions including India, Middle East, and Africa.
In, many emerging countries demand for air continuing is expected to grow in line with population and economic growth. For instance, Saudi Arabia’s air-conditioning market is expected to grow at the compounded annual growth rate of around 8.7 percent for the next five years. In India, total consumption for air conditioning is projected to climb as much as tenfold over the coming decade and in Brazil, demand has tripled in just five years.
There are several reasons the demand for air conditioning continues to climb, these include gains in living standards in many countries, advances in technology, and the impact of innovations have had on increasing the affordability of such units.

How air conditioning has changed the world

Today air conditioning is not only about keeping people cool, it is also about controlling environmental conditions in offices, factories and trains. For many, it is ensuring a comfortable temperature to work, but industrial processes, air conditioning is about maintaining air temperatures but also humidity.
In fact, it has changed the appearance of buildings. In the past buildings were to designed to be passively cool, unlike modern designs, that rely on artificial cooling. Because of artificial cooling, architects have given up the use of passive cooling techniques including the use of thick walls, high ceilings, blinds, balconies, courtyards, and windows facing away from the sun, to keep cool. In fact, Prof. Derek Clements-Croome at Reading University suggested in a phone call, “Traditional heavyweight buildings are naturally cool in hot countries, as compared to lightweight modern buildings, which unless well ventilated can be boiling.”
For instance, air conditioning has changed not on the design of buildings but also the economy of the American South. Before air conditioning, buildings tended to have verandas and shutters to keep buildings cool, and the region’s economy did less well than Northern cooler parts of the U.S. Now the American South is booming, in part due to air conditioning as firms like GE relocate their locomotive building factories to Texas.

Park 288 in Houston, Texas (

Air condition has also brought benefits by improving the ability of people to work, study and play. According to Geoffrey Heal and Jisung Park, a hotter-than-average year is bad for productivity in hot countries but good in cold ones. They conclude that individual productivity peaks at between 18 C and 22 C. If the room is too hot, employees are more likely to feel sleepy and their concentration level drops dramatically.

Problems with artificial air conditioning

There are several problems with artificial air conditioning; these include the impact on the surrounding environment and energy use.
Using air conditioning can be energy hungry; one study found that an American central air conditioner system used 11 kWh a day, equivalent to what an average Moroccan uses in a week. The town of Wellesley, Massachusetts has found that a typical American home central air-conditioning system, working six hours a day is likely to use 900 kWh per month. At a cost of $0.134 per kWh, this amounts to $120.60 per month. A large 12,000 British thermal unit (BTU) installed in a window, running six hours each day will consume 270 kWh, at a cost of $36.26 per month. But, a smaller 6,500 BTU room air-conditioning unit could use 144 kWh at a cost of $19.34 per month. However, in the heat of summer, energy usage is likely to be higher than in the winter.

A shop assistant adjusts a Haier air conditioner in a store in Queens, New York (

Demand for air conditioning is adding extra pressure on power companies in many countries including India, Brazil and Saudi Arabia. In India, total consumption for air conditioning is projected to climb as much as tenfold over the coming decade; air conditioners already reportedly account for a staggering 40 percent of all electricity consumption in Mumbai, India. More than half of Saudi Arabia’s summer electricity consumption, which was generated by burning 1 billion barrels of oil a year, also goes on air conditioning. Air conditioning sales in China have nearly doubled in the last five years alone, contributing to a surge in electricity consumption. In addition, steep increases in electricity demand in southern European countries are being blamed on the demand for air conditioning.
Another problem is that the growing usage of air conditioning is creating heat islands over cities like London, New York, and Singapore. An Arizona State University study of Phoenix, Arizona, found that the waste heat produced by air-conditioning units are thought to have increased city nighttime temperatures by over 1 C for some urban locations. It is a common experience for commuters traveling into London, from rural area to notice that London is a few degrees warmer.
However, it can also impact on user’s health and fitness, evidence suggests. It can weaken the body’s ability to cope with extreme temperatures, aggravate fatigue and poorly maintained systems can cause sick building syndrome, where many people in a building can feel unwell.

Back to passive air conditioning

Rising power bills caused by air conditioning are encouraging building owners to prevent their buildings getting hot in the first place, by using passive cooling techniques.
Increasingly, we are seeing buildings fitted with solar blinds or shades to reflect the sunlight, planted with trees to shade buildings, walls painted in bright colors to reflect the heat and keep the inside cool. In Los Angeles, the city council is painting roads white, to lower temperatures in urban areas.
Another choice is practicing heat modulation and dissipation techniques. Prof Clements-Croome suggests: “Traditional methods such as opening windows to let the air in can help.” He adds, “It encourages a draught, enabling the wind to pull air through the building. Wind ventilation is the easiest, most common, and often the least expensive form of passive cooling and ventilation.”

Another approach to keeping buildings cool is stack ventilation, which uses temperature differences to move air. Hot air rises because it is lower pressure. A good example of this is Britain’s Houses of Parliament. The many towers you see in the building like Big Ben and the Victoria Tower original purpose was to keep the air fresh, with colder outside air replacing the rising warm air through designed inlets placed near ground level. Examples of such modern office buildings using passive air conditioning include the Energon in Germany, the Building Research Establishment in England and the Solar XXI building in Portugal
Passive air-conditioning systems save energy and benefit the internal and external environment of buildings. They are especially useful in countries where power supplies are tight and prone to power cuts. Nevertheless, for building owners and operators, passive air conditioning has another benefit—keeping energy bills down and aiding in the comfort levels of users.

SEE MORE: The challenge of keeping cool by Nicholas Newman

about the author
Nicholas Newman
Freelance energy journalist and copywriter who regularly writes for AFRELEC, Economist, Energy World, EER, Petroleum Review, PGJ, E&P, Oil Review Africa, Oil Review Middle East. Shale Gas Guide.