This story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

When they flick off light switches or ease off the gas pedal, many Americans feel they are doing their part to save energy. But the authors of a new survey say that consumers consistently ignore larger changes—buying more efficient appliances or vehicles, or insulating their homes—that would cut fuel consumption far more dramatically.

The research from Columbia University’s Earth Institute and the university’s Center for Research on Environmental Decisions is the latest attempt to probe the psychological roots of the energy problem, and to understand why it has been so hard to realize reductions in greenhouse gas pollution.

The Low-Impact Approach

The survey of 505 people from 34 states, which appears in this week’s Proceedings of the National Academy of Sciences, showed that consumers gravitate to “low-effort, low-impact” actions on energy, rather than big-ticket investments that might reap higher rewards. The largest group, nearly 20 percent, cited turning off lights as the best approach to save energy—an action that the study authors said actually could affect energy budgets relatively little. Similarly, the respondents overestimated the energy saved by reducing highway speed from 70 to 60 miles per hour on a 60-mile trip. The authors said that speed reduction likely would save less than a half-gallon (1.5 liters) of gasoline.

But only about 3 percent of the survey respondents cited more efficient cars or appliances, and about 2 percent cited insulating their homes—buying decisions that could in fact cut U.S. energy consumption dramatically if done on large scale.

“When people think of themselves, they may tend to think of what they can do that is cheap and easy at the moment,” said lead author Shahzeen Attari, a postdoctoral fellow at Columbia University’s Earth Institute. She said the people surveyed tended to believe in “curtailment” rather than efficiency. “That is, keeping the same behavior, but doing less of it,” she explained. “But switching to efficient technologies generally allows you to maintain your behavior, and save a great deal more energy.”

Of course, some energy experts points out that in a large house with inefficient incandescent light bulbs, turning out lights in fact can amount to a large cut in consumption. “If you’re using 100-watt light bulbs, that’s not an inconsequential amount of electricity,” said Tom Simchak, research associate at the Alliance to Save Energy, a Washington, D.C.-based nonprofit. He said it’s understandable that consumers would think first of turning off lights or unplugging appliances to save energy, “since those are free.”

“If you’re calculating the payback of a new air conditioning unit, it may be two or three years until you see the savings, even though it may save lots of energy,” said Simchak. “But the moment you flip the light switch [off], you are getting your money back.”

Simchak said, however, that the paper points out a legitimate concern: “People don’t recognize how changing out appliances can save a lot of money,” even though the payback can take time.

One of the factors that could be skewing perceptions is the way that energy efficiency information has been communicated, both by policymakers and by industry. For instance, Attari’s team cited a 2008 paper by Duke University researchers, “The MPG Illusion,” which showed the use of “miles per gallon” as an efficiency standard can be misleading.

What seems like a modest change in mpg terms, a switch from a 10-mpg gas guzzler to an 11-mpg sport utility vehicle, would actually save 100 gallons over 10,000 miles. That’s the same as a switch from a relatively high efficiency 33-mpg car to a 50-mpg hybrid-electric model. “Even small improvements in mpg can be a lot of gas savings if you’re driving a really inefficient car,” said the study co-author, Richard Larrick, professor at Duke University’s Fuqua School of Business.

The survey by the Columbia University researchers, Larrick said, points out the need for people to get better information on the changes that would make a big impact in their home energy use.

Home “Gas Guzzlers”

“You need to look at your refrigerator or your air conditioner and realize it’s the SUV of your house, and there is an opportunity for big savings if it’s 10 or 15 years old,” to switch it out for a newer efficient model, Larrick said. “I do sometimes worry that the focus on light bulbs is creating a lot of 33-mpg-to-50-mpg” results—smaller savings than would be realized by a focus on appliances that are using far more energy.

Ironically, survey respondents who reported that they engaged in more energy-conserving behaviors actually had less accurate perceptions on the best steps for reducing fuel and power consumption. Attari said that might be a reflection of unrealistic optimism about the actions they personally were choosing to take. Also, “single-action bias” might be at work—meaning that people tend to be willing to take one or two actions to address a perceived problem, but attention fades after they believe they have done all they can.