One cool century

WASHINGTON -- Pete Kristiansen is wrapped in a blessed cocoon of chilly air.

They keep it cold at the suburban Jiffy Plumbing & Heating office, so cold the air-conditioning technicians sometimes put on coats when they arrive. By the very nature of their jobs, they spend their days where the AC doesn't work. So when they return, in their sweat-soaked shirts, the icy blast is a welcome kiss of comfort.

Usually Kristiansen would be out with the others, putting in a 14-, 15-hour day. His customers would be sweaty, their homes stifling, attic temperatures reaching as high as 160 degrees.

But today Kristiansen just couldn't take it. His first truck broke down. And the replacement is just not livable.

It doesn't have working AC.

"If I've got to go into 100-degree houses all day," he says, "I'll be damned if I'll sit in a 110-degree truck! I just had to draw the line."

There are places, of course, that never have air conditioning. Small corner bodegas. Older apartments and houses. Outdoor job sites.

For most of us, though, summer comes with refrigerated offices and malls, bedrooms cooled to optimal sleeping temperatures -- at least for the one in control of the thermostat. Without air conditioning, we would be limp, damp, foggy, irritable. We would be utterly miserable.

And so let us now praise the invention of air conditioning, which arrived 100 years ago, and has changed our entire world.

With air conditioning, we have conquered what Robert Thompson calls the "comfort frontier."

"For a long time, there was still a sense that a little taste of Walden Pond would waft in through your curtains, through your screens, that you'd wake up with the birds chirping," says Thompson, a Syracuse University professor specializing in popular culture. "Central air conditioning changed all that. It got to the point where people didn't even know how to open their windows anymore. And the window unit -- it just drowns out any sounds of the outside."

We have air conditioning in our cars, our garages -- even some yards, where huge portable units can be installed at corporate or high-society outdoor gatherings. We have dual-zone climate control in our cars. We have zoning systems in our homes.

Phoenix has professional hockey. Houston, with some of the nation's most unbearable heat and humidity, is the fourth-largest city in the United States. Las Vegas rose out of a desert to be one of America's playgrounds. People have moved in droves to areas of the country they would have considered unappealing, if not downright miserable, to live year-round before.

Even tractors come with air conditioning.

Think of Washington: Built on a swamp, Washington is legendary for sweltering summer humidity. Legend has it the Brits used to receive hardship pay to work here in the summer. Congressional sessions ran only in the cooler months; politicians abandoned town once the heat rolled in.

Then came AC. The House of Representatives was air-conditioned in 1928, the Senate in 1929; the White House got central AC in 1930. Public office buildings followed suit. A few decades later, residences became air-conditioned. The town changed.

Some of us might still wax nostalgic for pre-air-conditioned America. For the thought of a breeze. Porch sleeping. Lazy evenings on the front porch swing, talking to the neighbors. The smell of grass. Outdoor baseball.

Then we walk outside, back into the full blast of summer, and we find ourselves worshiping one man, Willis Carrier.

Air conditioning was not created for people. It was created for machines. A printing press, to be precise.

The Sackett-Wilhelms Lithographing and Publishing Co. of Brooklyn was having trouble printing clear images during summer, when heat and humidity did things to the paper, misaligning the printing process. Willis Carrier, a 25-year-old engineer for Buffalo Forge, was charged with solving the problem. On July 17, 1902, he did just that -- with the world's first scientific air conditioning system.

How did it work? That's a little complicated. Richard DiDio, an associate professor at La Salle University, likes to use the refrigerator to explain the process (refrigeration technology predated air conditioning by nearly two centuries). It's a thermodynamic cycle, he explains.

A liquid with a low boiling point, called a refrigerant -- once Freon was the big one, but it has fallen out of favor because of environmental concerns -- is allowed to evaporate. As it evaporates, the refrigerant absorbs the heat in the air. That absorption cools the air and the refrigerant gets hotter, its temperature rising to a boil.

Then the boiling liquid is quickly compressed, and the process starts all over again.

"That's the cycle," DiDio says, "and the air conditioner is somewhat similar, only now you're living inside the refrigerator."

The thought of cooling us wasn't Carrier's first priority. Several years later, though, he and six buddies started their own company, focusing on that concept. Today, Carrier, based in Syracuse, N.Y., brings in annual revenues of $9 billion, doing business in more than 170 countries.

And the technology keeps growing.

"I won't go so far as to say it's on the horizon -- that we'll have it in a year or two -- but in the future there will be systems that adjust automatically to the number of people in the room, or even the kind of clothes you are wearing," says Jon Shaw, Carrier's senior manager of communications.