Networked digital devices may cause rising energy use, although devices save energy locally Since the dawn of the internet, a digital revolution has transformed life for millions of people. Digital files have replaced paper, email has replaced letters, and cell phones provide access to many services that facilitate daily life. This digital revolution is not over, and there is now a growing deployment of technologies grouped under the term “Internet of Things” (IoT)—a worldwide network of interconnected objects that are uniquely addressable via standard communication protocols ( 1 ). By 2020, there may be as many as 30 billion objects connected to the internet ( 2 ), all of which require energy. These devices may yield direct energy savings ( 3 , 4 ), but it is much less clear what their net effect on the broader energy system will be. Scientists and regulators will need to work together to ensure that the IoT's benefits do not come at the expense of rising energy use.