Mr. Weijo and Mr. Brown of Pacific Northwest Laboratory did a year long research on the way the AC market has been growing along with housing from 1995 to 2010. Though the installation of AC has been growing, it has not matched the growth of housing across the United States. Strangely, in the south where one would assume the need for lesser air conditioning, central units have been as high as 47.3%. The penetration of air conditioning has been lowest in the west where close to 61.2% of houses don’t have air conditioning. All the information is available in the informative Infographics shown below.