Many people are profoundly misinformed about how much energy they use and how much they can save, according to a study published in PNAS on Monday. A sampling of adults showed that most people incorrectly think that actions like turning off lights and unplugging idle cell phone chargers save more energy than using more efficient appliances, like compact fluorescent light bulbs. They also proved to be poor at estimating differences in energy use between various appliances, suggesting that the public needs a significant re-education on energy use.

The energy study had two parts: first, people were asked what was the single most effective thing they could do to conserve energy. Next, they were asked to estimate the energy use of nine household appliances, using a 100-watt light bulb as a reference point, and the amount of energy saved by six household activities, such as line-drying clothes instead of using an electric dryer.

Efficiency vs. shutdown

With the first question, researchers found that 55 percent of the participants thought the most energy could be saved by trying to curtail the amount of energy they used—turning off lights, adjusting the thermostat, and so on. But this answer, for the most part, is incorrect. Much more energy can be saved by pursuing efficiency and installing energy-sipping appliances, since there's only so much we can or are willing to shut off.

The gap between curtailing inefficient appliances and using efficient ones can be large, so it shocked the researchers how many people underestimated it. An example: a 100-watt bulb that is on for six hours uses 600 watt-hours. By leaving it on for one hour less, you save 100 watt-hours. On the other hand, a 15-watt fluorescent bulb could be left on for all six hours and only use 90 watt-hours, saving 510 watt-hours over the incandescent bulb.

Still, consumers have managed to ignore this margin in favor of flicking a switch a few more times a day. Only 11.7 percent of the participants seemed to realize that more efficient appliances trump attempts at curtailing use of regular appliances—this small group gave answers like "use fluorescent light bulbs."

When researchers asked participants to estimate how much energy various activities used or saved, they seemed similarly misinformed. For example, many correctly said that laptop computers use less energy than desktops, but undersestimated the savings by a factor of ten. Some participants were also completely wrong in their estimates. For example, many thought that line-drying clothes instead of using a dryer saves more energy than using cold water instead of hot in the washer. In reality, the opposite is true: line drying saves less energy than a cold wash.

They weren't always off—most correctly said that it takes less energy to make glass bottles and aluminum cans from recycled materials than from virgin materials. However, they incorrectly thought that making glass bottles requires less energy than aluminum cans.

Where did we go wrong?

The researchers found that two factors made for a major improvement in people's responses: a facility with math and a pro-environmental stance. This might suggest that smarter consumers know more about energy stuff. Except the rest of the data showed that smarter consumers didn't know more about energy stuff.

Many other statistics like income, education, position on climate change, home ownership, and age, which normally indicate a sharp consumer, were not at all predictive of energy understanding. Worse, participants who reported taking the most steps toward energy conservation had the least accurate perceptions of which ones saved the most energy.

Many of the correlations between participants' profiles and answers were puzzling to the authors. They submitted that some of the incorrect energy estimations were due to an effect called the "anchoring-and-adjustment-heuristic," where forcing people to anchor their measurements to some fixed item, like a 100-watt lightblulb, makes them slightly underestimate large differences and overestimate small ones.

They had less doubt about the difference between curtailment and effiency PR. Curtailment activities, they said, have been way oversold to consumers, to the point that they have a very inflated view of how much energy is saved by unplugging or turning off something.

Consumers' favoring of curtailment likely also has to do with the related costs of effort and money. Turning off a light does save energy and is easy and cheap, while carting in a new washer and dryer or buying fluorescent bulbs and installing them requires much higher costs and effort.

The authors propose that scientists should do a better job of relaying information about energy use to the public to close the knowledge gap. Likewise, they suggested future campaigns for reducing energy use should focus on addressing and busting misconceptions, like the overblown effects of curtailment, and replacing them with new practices.

PNAS, 2010. DOI: 10.1073/pnas.10015091078 (About DOIs).

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