Science

Hot and Bothered

Air conditioning isn’t bad for you or even (relatively) for the planet.

NYC Heatwave
AC isn’t just about one’s social status and affiliation; it’s a matter of public health: Heat waves kill at least as readily as cold, causing hundreds of deaths every year in the U.S. Photo by Stephen Chernin/Getty Images

“Why is America so over air-conditioned?” asks the New York Times in last weekend’s Sunday Review. The article’s premise will be familiar to certain members of the paper’s demographic, for whom it’s self-evident that window units are not so much a source of comfort as a sign of gross indulgence. These people love to hate AC, and they drive me nuts.

The war on air conditioning, headquartered in the high-rent neighborhoods of coastal cities in the North, has lately grown more fervid. AC isn’t just unnecessary, the cooling contras say, but an engine of apocalypse. When we turn air conditioning on to cool ourselves, we’re burning fossil fuels, which makes the planet hotter—and that means we’ll have to cool ourselves some more. Even the Pope has weighed in against this supposedly voluptuous, self-destructive spiral. Last month, in his historic encyclical on the environment, Francis called out the “increasing use and power of air-conditioning” as cause for grave concern. “An outsider looking at our world would be amazed by such behavior,” he said.

The New York Times agrees: “It seems absurd, if not unconscionable.” But the 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. 

Anti-AC sentiment persists in spite of basic facts, and without convincing evidence. It relies instead on naked ideology and posture. To rail against the air conditioner is a way for cosmopolitans to claim their bona fides, and to place themselves in opposition to irresponsible, American excess. When they proudly say they’d rather use electric fans, they show their neighbors that they’re tasteful intellectuals—right-minded and upstanding. That is to say, they’re members of the brrr-geoisie.

They’re also victims of a blinding bias. The brrr-geoisie are thermal bigots: They put a moral value on the thermostat that doesn’t correspond to common sense. Heating, good; cooling, bad—that’s their moral calculus. Why discriminate among degrees? They have no cogent answer. It may be true that America is overcooled, but then again it’s also overheated. No one writes op-eds to make the latter point.

This week’s essay in the Times tries to fuel the anti-cooling dogma, but its energy is wasted. There’s no logic here, only specious and confusing claims backed up with shoddy science. “As infants we learn to associate warmth with the safety of our parents’ arms,” author Kate Murphy writes. “Our subconscious equates cold with vulnerability, which partly explains why people can be so miserable when they are chilled.” That must be why we’re so averse to eating ice cream: It makes us feel unsafe.

This hot air goes on for several paragraphs. Preschool facts and utter nonsense get dressed up in the wooly scarf of scientific jargon. “Since thermoreceptors (nerve cells that sense temperature changes) are on your skin,” she says for the benefit of no one, “the more of it you have exposed, the colder you are going to feel. Sixty-eight degrees feels a lot different if you are wearing a wool turtleneck, slacks and boots versus a poplin sundress and sandals.” So true!

How does this relate to air conditioning? A blast of cold, like you’d get when you walk into a chilled lobby on a summer day, “may feel good at first,” she writes, but the rapid shift in temperature can make “the hypothalamus go nuts, intensifying physical and psychological discomfort when the initial pleasure wears off.” I’ll admit that does sound pretty bad—no one wants a nutty hypothalamus. But the essay doesn’t tell us if these rapid shifts in temperature cause the same derangement during winter. Would it discombobulate the diencephalon to warm yourself beside the fire on a frigid night, or sip a steaming cup of cocoa?

The wrongness of the essay doesn’t end with awkward stabs at neuroscience. At one point it proposes that building managers might be setting thermostats too low because they’re “heavyset, as body fat is the ultimate heat insulator.” This has the science somewhat backward: Body fat is indeed an insulator, and that means that it prevents a person’s core body heat from seeping out into her skin. (You’ll recall the skin is where you’d find a person’s thermoreceptors.) As a result, a fat person might end up feeling colder than a skinny person, and not the other way around. (The exact relationship between body composition and perceived warmth is very complicated and varies with context. As a rule of thumb, you’ll probably be warmest if you happen to be both fat and muscular.)

According to the Times, overcooling makes people less happy and productive. We “work less and make more mistakes” at 70 degrees than we do at 75 degrees, the essay says, citing figures from an observational study of 19 workers at a sales office in Piscataway, New Jersey. While it’s true the researchers found a correlation between ambient air temperature and workers’ “correct keystrokes,” the result applied only to a subset of their study group—the seven people who happened to experience temperature shifts of more than 7 degrees during the study. Even among this smaller group, the researchers found no effect of temperature on a second measure of productivity, “mouse-click rate.”

Meanwhile, other studies done in natural work settings find that overheating has a large—and decidedly negative—effect on employees. One recent paper looked at 70 factory workers exposed to different temperatures and found that those in hotter conditions made more mistakes and showed signs of temporary cognitive impairment. Controlled experiments in the lab generally come to the same conclusion. And if you go by research from Japan, where office thermostats are set at 82 degrees during the summer, some two-thirds of employees describe themselves as being uncomfortable and unproductive in July and August.

Yet the Times op-ed doesn’t stop at claiming that AC makes us unproductive. It also alleges that too much cooling turns us “untrusting, uncommunicative, and unfriendly.”  There’s a hint of truth in this: Research on what is sometimes called “embodied cognition” has found that temperature cues (an ice pack on your hand, a heating pad on your chair, a cold or hot beverage in your hand) can make a person slightly more or less inclined to seek out social contact or inclusion. But the nature and magnitude of this effect varies quite a bit, depending on such factors as the mood and situation of the subject and her baseline personality. What’s more, there’s plenty of other evidence linking hot weather to expressions of mental illness. A recent study of several decades’ worth of suicide data from Toronto and Jackson, Mississippi, found that people were more likely to kill themselves during heat waves.

The latter fact reveals that the squabble over air conditioning isn’t just about one’s social status and affiliation. It’s a matter of public health. Heat waves kill at least as readily as cold, causing hundreds of deaths every year in the United States. Next Monday marks the 20th anniversary of a tragic spell of brutal weather in Chicago that caused more than 700 heat-related deaths within a single week. Among the most affected were the impoverished elderly, who either had no AC units or could not afford to use them.

But for comfortably climate-controlled members of the brrr-geoisie, February must seem far more deadly than July. It’s a function of the climate where they live. In New York City, winters are unlivable while summers merely suck. In another state, that formulation might have to be reversed.

It’s no wonder, then, that quarrels over air conditioning reverberate in politics: The hotter, redder states need more cooling than the icy, bluer ones. It’s not just a matter of geography but one of race and class: Black and impoverished families are more likely to be without a mode of cooling, other things being equal, and they’re more concentrated in the South, where cooling helps the most. Disparities in access to AC produce the sort of tragic inequalities that should make people uncomfortable: According to recent data from the Centers for Disease Control and Prevention, black Americans are 1.4 times more likely than white Americans to die from cold weather, and 2.6 times more likely to die from heat-related illness.

These grim facts are well beyond the purview of the essay in the New York Times, which only asks us to turn the AC down a bit—not to push our units out the window. But its rhetoric suggests a narrow-minded point of view that holds up the radiator as a natural right, and the AC as self-indulgent. That’s provincialism in the guise of ecoconsciousness. To inveigh against the air conditioner is to claim that someone else’s discomfort isn’t worth the same as yours. It pretends that feeling hot and feeling cold are in different moral categories. If you’re shivering, please feel free to tweak your thermostat. Just don’t make it a crusade.