The average person is only vaguely aware of whether he or she is wasting energy at home. And most people do not automatically make sacrifices for the common good.

Both behaviors can change with a few creative social nudges, aided by clever technology, which build on three lessons that social scientists say are key to changing what people do. First, make the monetary cost of choices visible. Second, enlist social norms; if people are doing worse than their neighbors, let them know about it. Third, make it easy for individuals to take a different path; try to put change on automatic pilot. Let’s apply these lessons to energy conservation.

Make costs visible. It is hard for homeowners to gauge their energy use in real time. When they turn up the heat, they don’t really know how much that energy is costing them. If the thermostat could tell them immediately, they would be more likely to change their behavior and conserve.

In one trial, the Southern California Edison utility gave consumers an Ambient Orb, a little tabletop ball that communicates wirelessly with the power grid. The sphere glows red when electricity prices are high (during peak demand periods, which shift with the weather and time of day) and green when prices are lower. After several weeks, homeowners reduced their consumption during peak periods by 40 percent.

Enlist social norms. A British company, DIY Kyoto, has designed a book-size console called the Wattson that wirelessly connects to a home’s energy meter and displays usage in watts or British pounds. Blue numbers tell residents they are using less electricity than is average for a home like theirs; red numbers mean they are being power hogs. The designers know that people dislike doing worse than their neighbors, especially when money or values are involved.

Consider a 2007 study by P. Wesley Schultz of California State University, San Marcos, of hundreds of households in that college town. All the residents were informed about how much energy they had used in previous weeks. They were also told the average consumption in their neighborhood. In the following weeks, the above-average residents significantly decreased their consumption. Unfortunately, the below-average customers allowed their usage to rise. So Schultz had a smiley face added to a below-average bill and a frown to an above-­average bill. This simple nudge prompted excessive users to cut even more yet discouraged savers from drifting higher. A number of companies are now experimenting with energy bills that show consumers how they compare with their neighbors.

Make change simple. Some of the best eco-nudges make energy-saving steps easy, even automatic. One example involves the plastic keys that guests insert into hotel-room doors. In many hotels, especially in Europe, after guests enter their room they must place their key in a slot inside the room to be able to turn on the lights. When a guest is about to leave and removes the key, the lights and air-conditioning go off (the clock radio stays on). Hotels are increasingly arranging rooms this way because they know their customers have no incentive to turn off the lights, yet the hotel must pay the utility bill. The up-front cost saves money in the long term. Why don’t we have a similar switch in our homes?

Eco-nudges alone cannot save the planet, of course. But they can change people’s awareness and behavior, which can go a long way.

Note: This article was originally published with the title, "Exploiting the Shame Meter".