The National Academy of Engineering (NAE) ranks air conditioning and refrigeration number 10 in its list of the 20 greatest engineering achievements of the 20th century. The selection was based on the impact the technology had on the quality of life during the last century (www.greatachievements.org/).
As NAE stated "Air conditioning and refrigeration changed life immensely in the 20th century. Dozens of engineering innovations made it possible to transport and store fresh foods and to adapt the environment to human needs. Once luxuries, air conditioning and refrigeration are now common necessities which greatly enhance our quality of life."