Home air conditioning cut premature deaths on hot days 80 percent since 1960

As winter begins to tighten its grip on much of the United States, air conditioning doesn’t seem like much of a survival strategy. But a new study has found that home air conditioning played a key role in reducing American death rates over the past half-century, by keeping people cool. 
The installation of air conditioning in American homes is the reason why the chances of dying on an extremely hot day fell 80 percent over the past half-century, according to an analysis by a team of American researchers.
 
The findings, based on a comprehensive analysis of U.S. mortality records dating from 1900, suggests the spread of air conditioning in the developing world could play a major role in preventing future heat-related deaths linked to climate change. Very few U.S. homes had air conditioning before 1960; by 2004, that figure had climbed to 85 percent.
 
A team of researchers from Tulane University, Carnegie Mellon University, the National Bureau of Economic Research and the Massachusetts Institute of Technology examined patterns in heat-related deaths between 1900 and 2004. The group found that days on which temperatures rose above 90 degrees Fahrenheit accounted for about 600 premature deaths annually between 1960 and 2004, one-sixth as many as would have occurred under pre-1960 conditions.