Changes

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>

====Summary====

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. 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.