Article: Hot and Bothered: Air conditioning isn’t bad for you or even (relatively) for the planet.

[T]he case against AC has always been more a moral judgment than a scientific one. Summer cooling is no more damaging to the climate than the heating that we do in winter. In fact, it’s substantially less so, since the United States burns more fuel on radiators than it does on air conditioners. According to the most recent stats available from the federal government (which cover 2010), the average American household puts 40.4 million British thermal units into home heating, and just 9.3 million BTUs into home cooling. As I’ve pointed out before, this explains why the long-term shift in population from our coldest, Northern states into the hot and humid South has in sum reduced the amount of fossil fuel we burn to keep our houses at a comfortable temperature. Simply put: It’s more efficient to air-condition homes in Florida than it is to warm the ones in Minnesota. 

Europeans have trouble understanding the US's fondness for AC. They assume that our climates are like theirs. However, the climates in our midwest and east coast are very different from theirs, being much hotter and more humid during the summer. Only our west coast climates, mostly cool and humid or warm and dry, are similar to theirs.