Changes

[[File:Windcatchers.jpg|thumb|left|300px|Figure 1. Wind catchers are still used today to capture moving air and then funnel that air into buildings so that it can cool the structure. ]]__NOTOC__

By the early Medieval period in China, around the 8th century, large rotary fans began to be developed that were powered by water (Figure 2). Some fans would even blow over water or have water combined with the rotary motion of the fan to create something akin to air conditioning by cooling air over water and then having the cool air circulate. In the 17th and 18th centuries, early experiments with fan-like systems, which were manually or water powered, were used to help ventilate large halls or even mine shafts in Europe.  By the 18th and early 19th century, several innovations began to develop. Some were simple, such as streets beginning to have more awnings installed so that more shade would be available around towns. In 1837 William Fourness began to use steam to power fans. These were large devices that were not very portable, but nevertheless steam-driven fans enabled some cooling of larger spaces. By the mid-19th century, heavy curtains began to become fashionable in homes as well as high ceilings, although these were already evident in some early Medieval homes and palaces. The curtains would block out sun light from coming into the house during the day, while high ceilings would allow the heat to move higher up and away from the occupants in a room.  In the Victorian period, house plants also became popular, which helped to reduce air temperature in homes when plants released moisture. It was during this time also that public parks became popular, which were green spaces that also were relatively cooler than other built-up areas of urban areas. These became places people would flock to during the summer to relax.<ref>For more on Medieval and early modern innovations to help cool people and homes, see: Gantz, Carroll. <i>Refrigeration: A History</i>. Jefferson, North Carolina: McFarland & Company, Inc., Publishers, 2015.</ref>

Air conditioning became the main innovation for modern cooling. In 1902, Willis Carrier invented the air conditioner, with the first machine he invented also able to control humidity. Carrier used his knowledge of heating objects with steam and reversed the process so that objects became cool. Stuart W. Cramer coined the term air conditioning, where his device used water and "conditioned" it so that the moisture would then be used to create cold air.  The first house to have air conditioning was built in 1914, which was built in Minneapolis. David St. Pierre DuBose soon after created the first home with central air conditioning, by creating ducts throughout the house that would take the cold air from the air conditioning unit and blow it around the house. Refrigerators were also used in homes in the 1910s, with the first home refrigerators invented by Fred W. Wolf of Fort Wayne, Indian. Although refrigerators did not cool the home, they did allow people to store cold drinks and food, which helped to cool them during the hot summer months. In 1945, the portable air conditioning unit was created by Robert Sherman, allowing window units to be easily made and installed in older homes that did not have air conditioning.  In the 1950s, central air conditioning began to become more common and throughout much of the United States window units and central air conditioning became common. Although air conditioning certainly made many people's lives more comfortable, it did mean home builders did not always have to apply measures, such as gardening or building materials, that were always ideal for cooling, where builders could now choose cheaper materials and depend more on air conditioning to keep homes cool rather than use other measures.<ref>For more on the history of air conditioning, see: Basile, Salvatore. <i>Cool: How Air Conditioning Changed Everything</i>. First edition. New York: Fordham University Press, 2014. </ref>

Many ways to keep cool have been invented, including many techniques that are cheap and effective. For instance, simply planting trees or shrubs around a house could substantially cool a home. Air blown Airblown on water was known to cool places probably already by the Bronze Age in the 3rd millennium BC, but the Romans could have been the first to capitalize on this to create something akin to a central cooling system. Electric fans in the late 19th century and air conditioning in the early 20th century have now transformed homes. However, this has meant many homes today depend more on these modern conveniences and use materials, such as concrete, that have made cooling impossible without the use of modern cooling methods.