Energy efficiency products in America are typically promoted through the government's Energy Star program, a labeling system that identifies if a light bulb, appliance or a home achieves a minimum level of efficiency. Energy Star heavily promotes environmental sustainability as part of its labeling, assuming that customers are buying energy-efficient products to protect the planet. But is that a safe assumption?

A new study published in the Proceedings of the National Academy of Sciences suggests that it's not a safe assumption -- at least not when you're asking consumers to pay more for the product.

A team of researchers from the University of Pennsylvania and Duke wanted to know what kind of marketing strategies work for energy-efficient products when directed toward people with different political views. So they brought a group consisting of conservatives, centrists and liberals into a lab and gave them a choice between a compact florescent light bulb and an incandescent. The packaging included information on price, long-term performance and a label promoting the environmental benefits of the product.

Price determined how participants reacted to the environmental message. Even with a label about saving carbon emissions, conservatives and liberals were equally likely to pick the CFL bulb when it was priced the same as a conventional bulb. But when the CFL was priced higher, only 30 percent of conservatives opted for the efficient bulb when it included an environmental message. When the label was taken off and the bulbs were priced differently, more conservatives chose the CFL.

"The difference in response only appeared when the CFL was more expensive," said Dena Gromet, one of the authors of the report. "They all recognize the economic benefits, but when the values story comes into play, the response varies."

The graph below shows how drastically the environmental message influenced choice across the political spectrum.

The results of this study are both illuminating and somewhat predictable. The basic rules of marketing tell you that people approach products with different values that can dramatically influence how they respond to messaging. And previous studies have shown that conservatives respond to environmental messaging much differently than liberals do. Interestingly, the Energy Star labeling system has focused primarily on the environmental messages that can turn off a large swath of consumers from purchasing products.

"We think there's a lot more research to do in this area," said Gromet, who has also studied how political ideology impacts consumer choice in other markets. "This really drives home the importance of the message you're using and understanding which one to tap."

Energy efficiency andsolarcompanies pitching their products and services directly to consumers can learn from these results too. When asking consumers to pay a premium, communicating the non-environmental benefits may be a more effective strategy.

"We only focus on the energy-saving benefits," said Claire Johnson, chief of new markets and services at the energy efficiency company Next Step Living. "We don't really go outside that message."

And beyond basic advertising, direct customer engagement is an even better way to cut through biases. Johnson said that community-oriented education is often the most effective tool for helping consumers invest in efficiency.

"It's not just about advertising. It's educating through community programs. People often make decisions based on what their friends and community members do. It's our job to meet consumers on that level. The third-party endorsements through word of mouth are a big driver."

It's some sage messaging advice to consider in these politically polarized times.