How air conditioning made us expect Arizona to feel the same as Maine

One force has quietly shaped much of the world around us — our homes, our offices, the look of our cities, the migration patterns of Americans and the economic fortunes of different parts of the country.

That is: air conditioning.

It’s become so widespread as to be unremarkable, an assumed feature of every interior environment. Nearly 90% of Americans use some kind of air conditioning at home. It is humming in the background just about everywhere else you go: in your car, at the mall, on an airplane.

But our dependence on it increasingly poses a knotty problem, as the energy needed to power all this air conditioning produces emissions that contribute to the warming world. The more we use the thing that helps us cope with heat, the hotter it will get.

“This cycle where air conditioning is both the solution and the problem is really where we’re collectively kind of stuck,” said Daniel Barber, head of the school of architecture at the University of Technology Sydney.

Or, as he has written more bluntly: The comfort air conditioning gives us inside is predicated on the worsening instability of the climate outside.

Ronda Kaysen and Aatish Bhatia of The New York Times wrote this week about an illustration of this relationship. In some of the fastest-growing major metro areas in the U.S., including Las Vegas, the nights are rapidly getting hotter. That drives demand for even more air conditioning. And in fact, without air conditioning, it’s unlikely so many people would have moved to Las Vegas in the first place.

An essential part of what is going on here is that air conditioning has homogenized our indoor spaces, said Michael Osman, an architectural historian at UCLA. Air conditioning has given us the idea that the inside of a house in a Las Vegas heat wave should feel just like the inside of a house on a cool Massachusetts evening: It should be somewhere between 68 to 72 degrees Fahrenheit, with 30% to 50% humidity.

This sameness works on several scales: Every room inside a house should feel the same (forget that the root cellar is cool and the sun porch is warm). Every house should feel just like the house next to it (forget that their windows, eaves and ceiling heights differ). And every building should feel the same regardless of the climate outside (never mind if it’s in Florida or Michigan).

“All of a sudden, everything is homogenized,” Osman said. “And the consequences of that are dire.”

The energy needed to maintain that cool, comforting sameness is vast. But we’ve also forgotten, he said, why it might be useful to have differences — to have a part of your house that’s cooler on a hot day or to have a style of housing that makes sense in Florida but not Michigan.

This indoor sameness has effectively contributed to the outward sameness of buildings, making so many office towers similar glass boxes, so many residences the same suburban tract house. Many regional architectural traditions grew out of a response to the local climate, whether that meant a raised bungalow with a front porch in the South or an adobe building with thick walls that kept out the desert heat in the Southwest. But when the climate outside no longer matters, neither do these architectural differences.

Historian Raymond Arsenault warned of the broader consequences of this in a seminal 1984 article on how air conditioning changed the South. The region’s strong “sense of place” was becoming overwhelmed, he wrote, by endless identical chain stores, tract houses, glassy high-rises and enclosed shopping malls.

“General Electric has proved a more devastating invader than General Sherman,” he wrote.

The pursuit of a homogenized, climate-controlled interior has had other costs, too, in our ability to adapt to a changing future. All those glassy office buildings are hard to retrofit into housing, as many cities would like to do today. As hermetically sealed environments, they typically don’t have windows that open — a basic feature in any home (and one you’d certainly want in the event of a summer power outage).

Today, architects are trying to revive older ideas about how to contend with the climate without air conditioning (or, at least, with less of it). “Green” buildings and homes may increasingly take into account how to shade the hot summer sun or how to capture a natural cross breeze, depending on how the sun falls or the wind blows locally.

Barber and Osman both suggest the rest of us will need to rethink our expectations, too. Maybe we forgo air conditioning on a 78-degree day, to make sure we have it when it’s 100 out. Or we rethink the thermostat settings that leave some office workers wearing sweaters indoors in August.

Given that Americans have so thoroughly molded their modern lives around air conditioning, it will be hard to scale back their dependence on it. Just look at Florida, a state that could never have become a haven for seniors without the great homogenizing force of indoor climate control.

Before AC, the state “was a hard place to be old,” said Gary Mormino, a historian of the state.

And now if we asked Floridians to use less of it?

“We would probably nod our heads, and disobey or ignore such instructions,” he said. “Until power bills rise dramatically.”

This article originally appeared in The New York Times.