Which is greener, printed books or e-readers? Aluminum cans or glass bottles? The answers will surprise you.
Washing By Hand vs. Dishwasher
Assumption: Laboring at the sink with a sponge must be better than using that energy guzzler under the counter.
Reality Check: A dishwasher is something most folks are not: incredibly efficient. It can save up to 5,000 gallons of water per year compared with scrubbing by hand. That's because it uses roughly five gallons per load -- about one-fifth the amount most people use at the sink. And when less water is needed, your home's hot-water heater uses less energy. Just make sure you don't prerinse, which can squander an extra 20 gallons of water; don't run the machine with only a few dishes inside; and skip settings -- like heat-dry or rinse-hold -- that are stronger than necessary.
Go Greener: Look for phosphate-free detergent brands. The chemical can spread from wastewater and wreak havoc on lakes and streams, stimulating algae growth that deprives other aquatic plants and animals of oxygen.
Printed Book vs. E-Reader
Assumption: Because it's estimated that making one Kindle creates 22 times more greenhouse-gas emissions than producing a book, e-readers are eco-disasters.
Reality Check: The more you read, the more it makes sense to curl up with an e-reader. Though producing a single device takes a greater toll than making one book, you can download indefinitely. According to one study, once you read 23 books, the environmental hit of a Kindle is the same as the print version; download more and your e-reader trumps books. Of course, using it requires energy, but its energy-efficient screen needs less juice than most electronics. And downloading a new book takes only a few clicks, while buying a printed book means driving to a bookstore or having it shipped to you.
Go Greener: Unplug your charger when it's not in use so it doesn't suck extra energy. When you upgrade, recycle your e-reader at Amazon or Best Buy.
Plastic Wrap vs. Aluminum Foil
Assumption: Plastic is Earth's kryptonite; anything, including foil, must be better.
Reality Check: Experts estimate that plastic hangs around landfills for up to 1,000 years; aluminum foil, 500. Yet plastic wrap is the better choice per use. Because aluminum foil manufacturing is so complex (starting with bauxite ore mining), it's more energy-intensive and emissions-heavy. Making a square foot of plastic wrap uses about 30 percent as much energy and produces about one-tenth as many emissions as making foil. If you're a die-hard foil fan, make its eco-impact more comparable to plastic wrap by reusing the same piece four times.
Go Greener: When you can, skip both and opt for reusable glass containers.
Aluminum Cans vs. Glass Bottles
Assumption: Because aluminum manufacturing is so taxing, glass bottles should be your drink container of choice.
Reality Check: Making cans is still less arduous than making glass bottles. Plus, aluminum wins big in shipping: An empty 12-ounce can weighs up to 14 times less than a 12-ounce glass bottle; less weight means less fuel and fewer emissions in transport. And after the drink's been consumed, aluminum wins again: Recycling ten pounds of aluminum can save 37 pounds of carbon emissions, compared with one pound saved through glass recycling. The verdict: six-pack ahoy!
Go Greener: If you're a soft-drink lover, consider the SodaStream. The home sodamaker uses reusable canisters of CO2.
Related On HuffPost: What We Save By Recycling (list and captions courtesy of Earth911)