Environment
Ask Pablo
Summertime, and the living ain't easy in the heat. Should I run the air conditioner or electric fans?
Dear Pablo,
It’s too damn hot to sleep at night! To cool our bedroom on these summer nights, my husband and I can run either three fans or one air conditioner. Which is better for the environment?
Let me first answer the question and then I will discuss some alternatives. Based on additional information from the reader, I learned that each fan uses 50 watts of 120 volt electricity (150 total), while the air conditioner uses 530 watts of 120 volt electricity. Already we can see that the three fans use 28 percent as much energy. If the three fans are truly comparable in the level of comfort they provide, by all means, use the fans!
Fans work in three beneficial ways:
Once the sun has gone down, and things begin to cool off, they bring in the outside cool air. They can also vent a hot attic space that might otherwise radiate heat into your living space throughout the night. Stagnant (nonmoving) air creates a boundary layer around your skin. Because air is an excellent insulator (in fact, wall insulation is mostly air), this layer acts to impede the loss of excess heat. Even a light air current from a fan can significantly lessen the thickness of this boundary layer, allowing excess body heat to escape. Sweat creates an evaporative cooling effect that is limited both by the skin’s ability to produce sweat and by the air’s ability to take up excess moisture. Creating airflow allows more air to contact the skin and facilitates evaporation.
Air conditioners work in a different way. Inside an air conditioner is essentially a heat pump. This device uses the expansion of compressed gases to absorb heat energy from the indoor air (similar to how a compressed air canister or can of whipped cream gets colder as you use it), and then compresses the gases again to release that heat energy outside. Because a compressor is involved, some of the electricity used is lost to friction, heat and other inefficiencies.
Fans only use efficient electric motors, and so most of the electricity is converted directly into air movement. Interestingly, since there is some waste — heat generated by the electric motor — a fan in a closed room will gradually warm the room, but not by a significant amount. Using a fan can direct the cooling effects of air movement precisely where it is needed, namely straight at you, whereas an air conditioner works to cool the entire room. This is analogous to lighting. You can either light up an entire room in order to see what you are doing or use task lighting and save a considerable percentage of electricity.
Fans and air conditioners are not the only options. If humidity is contributing to your misery, you can use a dehumidifier to dry the indoor air and significantly decrease the heat index (the summertime equivalent of the wind chill factor). A machine called a swamp cooler uses the evaporative cooling effect by evaporating water with just a fan and a circulating pump. While it is less efficient than an air conditioner, you can always put a bowl of ice cubes in front of a fan in a pinch. And when all else fails, just get out of the house! Many public places such as coffee shops and bookstores are going to be air-conditioned anyway, so you might as well enjoy an iced tea and a good book until it’s cool enough outside to go home and open the windows.
In addition to electrical means, there are some other ways to keep your house cool, and that’s by keeping the heat out in the first place. Blinds may keep out the bright sunlight, but once the rays have passed through the glass, much of it turns into heat energy. It is more effective to keep the sunlight out of the window in the first place. Many buildings in Europe have sturdy external louvers to shade out the rays, and “green” architects are taking the sun into consideration when they design window overhangs that stop the summer sun but let in the winter sun.
Another consideration is installing “low-e” windows. The “e” stands for emissivity and means that the glass inhibits radiative heat flow. If a major remodeling is in your future, you can even consider building materials that have high “thermal mass,” meaning that they stay at a relatively constant temperature rather than fluctuating throughout the day. Tile floors, brick walls and even large sealed water tanks can keep your home warmer in the winter and cooler in the summer.
Got a question about the environment? Ask Pablo at AskPablo@Salon.com.
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Some parts of rural America are being ruined by an unstoppable new mining industry -- and it's spreading
Frac sand piles up at a processing plant in Chippewa Falls, Wis. (Credit: AP/Steve Karnowski) If the world can be seen in a grain of sand, watch out. As Wisconsinites are learning, there’s money (and misery) in sand — and if you’ve got the right kind, an oil company may soon be at your doorstep.
March in Wisconsin used to mean snow on the ground, temperatures so cold that farmers worried about their cows freezing to death. But as I traveled around rural townships and villages in early March to interview people about frac-sand mining, a little-known cousin of hydraulic fracturing or “fracking,” daytime temperatures soared to nearly 80 degrees — bizarre weather that seemed to be sending a meteorological message.
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Environmentalists are focused oil and gas, but a bigger carbon disaster may be brewing in the Pacific Northwest
A coal mine owned by Arch Coal Co. (Credit: AP/Matthew Brown) Coal is without question our dirtiest fuel source: When burned, it dumps toxins like mercury and nitrogen oxides into the air and packs an outsize punch when it comes to carbon emissions. Since America has a lot of it, though, we’ve tended to use a lot: Historically, around half our electricity has been generated by coal combustion plants. But as a result of sustained anti-coal activism, low prices for natural gas, and new EPA regulations on power plant emissions, Americans are using a lot less coal than we used to, and the future of the sooty stuff in this country is looking dim. So the U.S. coal industry is pinning its hopes on China. While historically most of our exported coal has gone to Europe, U.S. exports to China increased 176 percent between 2009 and 2010, and that number is likely to keep rising as the Asian market for coal continues to expand. The prospect of shipping coal across the Pacific is even more appealing considering that Western states like Wyoming and Montana have vast coal reserves in the Powder River Basin, one of the largest coal deposits in the world.
Continue Reading CloseAlyssa Battistoni writes about the environment and politics from Seattle. More Alyssa Battistoni.
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(Credit: cristapper via Shutterstock) Ever since I first watched my dad drive his chocolate brown Datsun 280 ZX back in the early 1980s, I’ve been inculcated to believe that driving — true driving — can only be performed with a stick shift. From that childhood experience, I came to see the manual transmission as a birthright passed down from my grandfather, to my father, and eventually to me via a series of tense, stall-filled lessons when I turned 16. In my case, after ripping apart the transmission one too many times, my dad went barking drill sergeant on me, eventually teaching me that a stick requires a special kind of focus, and that I needed to ease up more slowly on the clutch in order to get into first gear on those damn inclines. Through the experience, I learned to consider my stick-shifting skill a special talent with transcendent value.
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David Sirota is a best-selling author of the new book "Back to Our Future: How the 1980s Explain the World We Live In Now." He hosts the morning show on AM760 in Colorado. E-mail him at ds@davidsirota.com, follow him on Twitter @davidsirota or visit his website at www.davidsirota.com. More David Sirota.
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Continue Reading ClosePage 1 of 158 in Environment