When it comes to reducing carbon emissions, most of the attention has focused on new technologies like renewable power and electric vehicles, as well as their associated costs. But study after study shows that we can save both energy and a significant amount of cash through the use of energy efficiency technology that's already on the market. A Policy Forum in today's issue of Science suggests that the bottleneck isn't so much technological or economic as it is behavioral, and argues that the US needs to start performing tests of behavior-oriented programs.