Air-conditioning: Our Cross to Bear
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When it's hot and humid out and the air-conditioner's not running, America suffers. Babies break out in rashes, couples bicker, computers go haywire. In much of the nation, an August power outage is viewed not as an inconvenience but as a public health emergency.
In the 50 years since air-conditioning hit the mass market, America has become so well-addicted that our dependence goes almost entirely unremarked. A/C is built into our economy and our culture. Stepping from a torrid parking lot into a 72-degree, air-conditioned lobby can provide a degree of instantaneous relief and physical pleasure experienced through few other legal means. But if the effect of air-conditioning on a hot human being can be compared to that of a pain-relieving drug, its economic impact is more like that of an anabolic steroid. And withdrawal, when it comes, will be painful.
We're as committed to air-conditioning as we are to cars and computer chips. And a device lucky enough to become indispensable can demand and get whatever it needs to keep running. For the air-conditioner, that's a lot.
The costly care and feeding of AC
Like a refrigerator, an air-conditioner works by piping a chemical refrigerant through cycles of compression and expansion. The refrigerant absorbs heat from cool interior air and releases it to the hot air of the great outdoors. In doing so, it's impeded by the Second Law of Thermodynamics, or Entropy Law, which says that temperatures tend to even out -- that heat naturally flows from a hot to a cold area. So an air-conditioner has to mechanically compress the gaseous refrigerant into much hotter liquid form and pump it through outdoor coils from which it can release the heat it has absorbed. To do that requires a lot of energy, usually from a power plant or a vehicle engine.
Almost one kilowatt-hour of electricity out of every five consumed in the United States in a full year goes to cooling buildings. Much of the nation's excess power-generating capacity, which sits idle until needed to satisfy quick spikes in demand, has had to be built because of air-conditioning.
The electricity used annually to air-condition America's homes, stores, offices, factories, schools, churches, libraries, domed stadiums, hospitals, warehouses, prisons and other buildings (not including what's used to cool manufacturing processes and military facilities) exceeds the entire electricity consumption of the world's second and fourth most populous nations -- India and Indonesia -- combined.
The refreshing air that comes out of an air-conditioning system has an evil twin: carbon-laden exhaust from the utilities that power it. Just about 50 percent of U.S. electricity is generated with coal; 21 percent with other fossil fuels, mostly natural gas; 20 percent with nuclear fission; less than 7 percent with hydroelectric dams; and about 2 percent with biomass, wind and solar methods combined. Coal is the worst carbon dioxide producer, but all of those methods generate greenhouse gases and other ecological hazards during construction and operation.
In January, the Environmental Protection Agency (EPA) raised energy-efficiency standards for newly manufactured home central air-conditioners by 30 percent. Central air units typically last 15 to 20 years, so the new regulation will have little effect in the near future. Even if all units were replaced overnight, it would mean less than a 5 percent reduction in the power that's used to air-condition buildings. That's because the new rules don't apply to window units or to nonresidential air-conditioning.
The average household in the southeastern United States consumes almost twice as much electricity as the average household in New England, but air-conditioning doesn't account for that entire disparity. Southerners use a lot more power for all appliances, whatever the season. Of course, northern households consume more fossil fuel for heat, but in the dead of winter, heating cannot be dispensed with.
There is scope to save energy in both heating and air-conditioning by improving insulation. Energy used in heating could also be cut by setting thermostats at cooler temperatures, but air-conditioning is more of an all-or-nothing proposition. At a certain point on the thermostat, a stuffy, frugally cooled house or office becomes intolerable; a hot breeze from outside can be far preferable.
Driving from a cool home to a bracing workplace to a chilly supermarket would be a severe shock to the system if done in a non-air-conditioned car, so you'll find such cars only on "vintage" lots. Government tests have shown that running an air-conditioner can decrease a car's fuel efficiency by 4 miles per gallon. Excess fuel consumption is lower on the highway, higher in the city and incalculable when the engine and AC are left running in a parked pickup truck to keep a Dachshund comfortable.
(The long-running debate over whether you'll use less gas on a long highway trip by keeping the windows open -- which increases the car's aerodynamic drag -- or rolling them up and turning on the AC -- which puts an extra load on the engine -- seems to have ended in a tie.)
About 5.5 percent of the gasoline burned annually by America's cars and light trucks -- 7 billion gallons -- goes to run air-conditioners. That's equivalent to the total oil consumption of Indonesia, a petroleum-rich country with a population size comparable to ours. Four states -- California, Arizona, Texas and Florida -- account for 35 percent of that extra fuel consumption.
In years to come, we may be cranking air-conditioners up as high as they'll go to provide some relief from human-fueled global warming. But that will only aggravate the crisis. Air-conditioning accelerates the greenhouse effect not only by increasing the use of coal and other fossil fuels but also by releasing refrigerants.
Since the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, there has been a major shift in types of refrigerants used in air-conditioning and refrigeration. In particular, highly ozone-threatening chlorofluorocarbons (CFCs) are being phased out, most quickly in wealthier countries.
CFCs not only damage ozone, they also have the highest global-warming potential. But all commonly used refrigerants are greenhouse gases, and every pound produced is destined eventually to escape into the atmosphere during manufacture, use, recharge, recycling, disposal.
Fifty-six percent of refrigerants worldwide are used for air-conditioning buildings and vehicles. North America, with 6 percent of the world's people, accounts for nearly 40 percent of its refrigerant market, as well as 43 percent of all refrigerants currently "banked" inside appliances and 38 percent of the resultant global-warming effects.
Finally, in counting costs, it's important to consider not only fuel and refrigerants but also the materials -- steel, copper, plastics and a lot more -- that have gone into building up the nation's colossal tonnage of air-conditioning capacity.
Heating up the economy
As a device explicitly designed to outrun the Second Law of Thermodynamics, an air-conditioner vividly illustrates the inevitable destruction caused by all economic activity, a process first described by Nicholas Georgescu-Roegen, the godfather of ecological economics.
Georgescu-Roegen wrote in his 1971 book "The Entropy Law and the Economic Process" that despite the neat, closed-loop flow charts depicted in textbooks, the economic process "is not circular but unidirectional. As far as this facet alone is concerned, the economic process consists of a continuous transformation of low entropy into high entropy, that is, into irrevocable waste."
Georgescu-Roegen went on to demonstrate the futility of growth-dependent economic systems, showing that in human societies, "production" is a phantom, that economic activity can be represented by just two factors: consumption of resources -- concentrated energy, useful materials and our ecological life-support system -- and elimination of useless or less useful wastes. When all is said and done, he argued, an economy's only product is nonmaterial "enjoyment of life," which can be banked only in the form of memories.
As it creates fleeting enjoyment through a state of low entropy (in this case, an island of coolness in a sea of heat) but only by increasing entropy at an even faster rate elsewhere (by using up fuels and materials and releasing useless wastes), air-conditioning is a poster child for the inevitable decay that, according to Georgescu-Roegen, is a defining characteristic of economic growth.
It's no coincidence that when the first modern central air-conditioning system was installed back in 1902, it was to cool the New York Stock Exchange.
Sweaty and sweatless sweatshops
Air-conditioning systems have been traditionally classified into two categories: "process" or "comfort." For the first half of the 20th century, process air-conditioning was emphasized, making a wide range of manufacturing industries possible on a large scale. The 1999 National Building Museum exhibit " Stay Cool! Air Conditioning America" noted that "manufacturers of products susceptible to heat and humidity -- tobacco, pasta, textiles, chocolate and color printing -- commissioned many pioneering experiments in mechanical cooling." The economic growth stimulated by such industries, and by the digital and biotech revolutions of more recent decades, could never have happened without massive doses of process air-conditioning.
Today, process AC systems account for less than 8 percent as much energy consumption as comfort systems. With the big shift from manufacturing to low-wage, white-collar jobs in the past two decades, more people than ever are working in environments with comfort air-conditioning. But in most manufacturing plants, air-conditioning is targeted only where needed, more to the benefit of equipment, inputs and products than of people.
Traditionally, humans have dealt with heat and humidity by cutting back on physical activity in the middle of the day, maybe even taking a siesta. That was before economic "competitiveness" became a universally accepted end in itself.
A story by a trade magazine on a South Carolina plastic sign factory where workers endured summer temperatures of 110 degrees listed the effects of such heat on workers' performance: inconsistency, inability to concentrate, negativity, drowsiness, headache, fatigue and vulnerability to accidents. The magazine noted that "deliberate work slowdowns, walkouts and similar job actions occur over heat problems more than any other workplace hazard."
Managers at the South Carolina plant considered and rejected heat stress remedies recommended by the Occupational Health and Safety Administration, such as allowing longer rest periods in a cooler area. They calculated that a single daily rest period of ten minutes for their 100-person work force would cost them $20,000 over a summer. As a cheaper remedy that wouldn't slow production, the company settled on large, high-capacity ceiling fans, which cost 1/28 as much as air-conditioning to install and 1/10 as much in electricity to run.
The employees would probably have preferred to have both the improved air circulation and more breaks from the heat, but no workers were quoted in the article.
In summertime office work, air-conditioning is ubiquitous. It's used because it improves productivity, but results can be unpredictable. A 2004 Cornell University study showed how uneven airflow in cooled buildings often leaves some workers sweating while others might be blowing on their hands to warm them. In the study, workers typed only half as fast at an air-conditioned 68 degrees as they did at 77.
On balance, air-conditioning doubtless stimulates production where it's used; otherwise, employers wouldn't bear the expense. But that cool, dry air also pumps up demand for goods, and that's where it really gets things moving.
In describing the "Hot America" of the old days, the National Building Museum's exhibit painted a picture of a nation with sagging summer productivity, but more importantly, a nation with better things to do than to go shopping. It read in part,
Before air-conditioning, American life followed seasonal cycles determined by weather. Workers' productivity declined in direct proportion to the heat and humidity outside -- on the hottest days employees left work early and businesses shut their doors. Stores and theaters also closed down, unable to comfortably accommodate large groups of people in stifling interiors. Cities emptied in summers â€¦ Houses and office buildings were designed to enhance natural cooling, and people spent summer days and evenings on porches or fire escapes. They cooled off by getting wet -- opening up fire hydrants, going to the beach or diving into swimming holes.
A society that follows "seasonal cycles determined by the weather" is not an easy place to keep consumer demand calibrated to a constant, frenetic level. Movie theaters were among the first businesses to use air-conditioning, turning summer from a down-time into a boom-time. Now, almost all retailing depends on gathering large numbers of people into controlled environments and inducing them not just to buy what they came for but to "go shopping."
Marketing in America is an exceptionally wasteful means of extracting Georgescu Roegen's "enjoyment of life" out of valuable resources, and it's made possible partly by air-conditioning. In a summer without AC, the mall/big-box strategy of concentrated retailing would create little more than a hot stew of bodily aromas. With it, leisurely shopping has largely displaced noncommercial pastimes for many.
Air-conditioning can also make big purchases more attractive. You can't fully enjoy a jumbo-screen TV, a PC, an SUV or an RV unless you have AC. It allows you to grill steaks in the comfort of the kitchen, play indoor golf when it's too hot outdoors or, as President Richard Nixon used to do, enjoy your fireplace even in summer.
Have Americans just gotten soft, no longer willing to tolerate temperatures or humidities outside a narrow range? Maybe, but that's only part of it. The United States of 2006 is a product of the era of cheap energy, literally built for the air-conditioner, just as it's built for the automobile.
Lehigh University professor Gail Cooper documents how that happened, in her 1998 book "Air Conditioning America: Engineers and the Controlled Environment, 1900-1960." The post-World War II building boom, she observes, provided a golden opportunity to design buildings that would accommodate, even require, a central air-conditioning system, which at that time was a technological marvel in search of a market.
To make new buildings affordable despite the huge expense of cooling systems, homes were stripped of their heavier construction materials, large eaves, high ceilings, attic fans, and cross-ventilated design. (Cooper quotes the May, 1953 issue of Fortune magazine, which described the mass-produced home of the day as a "TV-equipped hotbox.") Office buildings became massive cubes; expensive, window-accommodating H- T- and L- shaped footprints were out. Extra insulation and other conservation measures were regarded as too costly; it wasn't the architects or builders who'd be paying the utility bills.
Much of that 1950s construction tradition has hung on throughout the Age of Air Conditioning. But change is coming -- slowly. By 2010, 5 percent to 10 percent of new, nonresidential construction is expected to be of certified " green buildings," which can be 30 percent more energy-efficient than standard buildings, while they use more ecologically friendly refrigerants. Part of the reduction in summer energy use can be achieved by use of natural ventilation, architectural shading and other built-in features. But making a serious dent in that 18 percent of all U.S. electricity consumption that goes to air-conditioning will require more than that.
No renewable energy source, and no combination of high ceilings, fans, rooftop gardens or other cooling strategies, can create the intensely cool, dry indoor climates to which most Americans have become accustomed in summer. Earth-friendly methods of construction and energy generation can provide some relief from the heat, but they cannot be expected to reverse the seasons. Summertime "comfort" will have to be redefined.
Meanwhile, the high standard that's been set for passenger comfort is helping doom efforts to run cars and trucks on alternative fuels. In 2005, air-conditioners in U.S. vehicles burned up the equivalent of the nation's entire fuel-ethanol production -- twice.
If the United States is going to get serious about the deep cuts in energy consumption that are needed, the whole idea of air-conditioning has to be questioned. In doing that, we can't depend only on ourselves, as individuals, to resist that most physically seductive of technologies. It will require big shifts in public policies that affect economic growth, achieved democratically rather than in quiet -- and artificially cooled -- White House meetings or raucous stock markets.
This story is the first in a two-part series on how air-conditioning has changed society. Next week: How air-conditioning may have helped elect George W. Bush.