Showing residential tenants how energy efficient a building is when they are looking at rentals nudges them toward making greener choices, a new study has found.

The report from The American Council for an Energy-Efficient Economy found that on a mock rental listings website, the presence of energy labels on listings encouraged a nationally representative sample of U.S. renters to select the most efficient listings 21% more often.

Coincidentally, renters chose the least efficient option 21% less often than when energy efficiency information was hidden.

The study also found that some renters were willing to pay more in rent for more energy-efficient properties. This might be because they care about the environment, but it could also be that they wanted to save on their energy bills, the report said.

The report said that if policymakers want to encourage consumers to make more energy-efficient property choices, they should make it mandatory for rental listings websites to show energy efficiency scores for properties.

For owners in sectors like multifamily or single-family rentals, the study also shows that prominently displaying good energy efficiency scores for properties would draw in consumers.

The study found the most likely renters to choose more energy-efficient properties were those under 45, those looking for apartments rather than single-family homes, and those in either the hottest or coldest climates.

It found that education or income levels didn't make a difference in how renters made choices. But the report did point out that showing renters how energy efficient a property is has a bigger impact on lower-income renters.