Quiz: What You Don't Know About Air Conditioning
Photograph by Stephanie Rausser, Getty Images
You know how much you rely on air conditioning to escape the summer heat. But what do you know about the energy that goes into keeping you cool?
In 1978, less than one-quarter of U.S. households had central air conditioning. By 2005, central air systems were cooling what percentage of homes?
- 25 percent
- 50 percent
- 60 percent
- 80 percent
Sixty percent have central systems, and if you count homes with room or window units, 84 percent of U.S. households have some type of air conditioning.
In 1914, the first home air conditioning system was installed in what city?
The Minneapolis mansion of Charles Gates, son of Gilded Age industrialist and gambler John Gates, is believed to be the first to have had an air conditioning system installed.
Because of air conditioning use, Americans use how much more electricity at the peak of summer than they do on coldest days of winter?
- 12 percent
- 22 percent
- 32 percent
- 42 percent
Summer peak electricity demand is about 22 percent higher than the height of demand in winter; many power plants—called “peakers”—are kept on hand to run only on those days of high demand. In many cases, the plants are old and expensive to run.
Chlorofluorocarbons (CFCs), once widely used in air conditioning, were phased out under the 1987 Montreal Protocol because of the damage they did to the Earth’s ozone layer. But policymakers are trying to address a remaining problem with the replacement chemicals now in use, hydrofluorocarbons (HFCs.) What is this problem?
- They are greenhouse gases
- They are toxic
- They are flammable
- They don’t work as well as CFCs
HFCs don’t hurt the ozone layer but, just like the CFCs they replaced, they are super-potent greenhouse gases, with hundreds or thousands of times greater global warming potential than carbon dioxide.
In China’s cities, by some estimates, ownership of air conditioning units was about 30 percent in 2004. How many urban Chinese households had air conditioning in 1992?
- Almost none
- 10 percent
- 15 percent
- 20 percent
There was virtually no room air conditioning in China in the early 1990s, but its use has spread rapidly.
If you have unused rooms in your house, how can you save money on central air conditioning?
- Close the air conditioner registers in the unused rooms and close the doors
- Open the windows in unused rooms to increase air circulation
- Add window air conditioners to the unused rooms, and run them only when the room is occupied
- Keep registers open in the unused room, and use a programmable thermostat to set back air conditioning at night or when no one is in the house
Lawrence Berkeley National Laboratory scientists showed that air leakage from hot, unused rooms with closed registers increased energy use throughout the home. The best way to save energy is to use less air conditioning throughout the home.
Turning on the air conditioner reduces the fuel economy of a conventional gasoline engine by about 20 percent, according to U.S. Environmental Protection Agency testing. What happens when you use the air conditioner in a hybrid gas-electric vehicle?
- It has about the same impact
- There is less loss of gas mileage
- There is a greater loss of gas mileage
- There is no impact on gas mileage
Studies show a greater percentage of gas mileage lost in hybrids than in gasoline vehicles, since the air conditioning has a greater absolute impact on fuel economy in high-efficiency cars.
Since 2005, Japan has tried to reduce office air conditioning through its Cool Biz campaign, in which workers are encouraged to dress light and informally. The need to save energy is even more urgent in the wake of the 2011 earthquake and tsunami. What’s the minimum office temperature in what is now known as Japan’s "Super" Cool Biz program?
- 68º F (20º C)
- 72º F (22º C)
- 78º F (25.5º C)
- 82º F (28º C)
Cool Biz offices must maintain a temperature of 82 degrees (28 degrees Celsius) or higher.
If you are driving slowly around town on a hot day, which should you do if you want to save gas mileage?
- Roll your windows down and drive with the air conditioner off
- Keep your windows rolled up and the air conditioner on to reduce aerodynamic drag on your vehicle.
Although vehicle drag might become a problem at high speeds, the air conditioner eats up more gasoline at slow speeds. About 7 billion gallons of gasoline a year, or 5.5 percent of U.S. passenger vehicle fuel use, goes to running the AC.
True or False? When differences in climate are taken into account, homes in Europe use air conditioning at about the same rate as households in the United States.
Although statistics are sparse, even warm European countries like Italy, Spain, and Greece use less air conditioning than is used in the United States. But energy analysts believe that air conditioning use in Europe and around the world is growing rapidly.
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