This paper illustrates the approach of Energy Life, a pervasive household sensoring and feedbacking system aimed at improving the energy conservation practices of the inhabitants. The concept of EnergyLife takes into account state-of-the-art knowledge of what makes a feedback intervention effective, which – at this stage of its development – can be synthesized into two main features. First, knowledge and action are to be synergically addressed by visualizing electricity consumption on the one side, and providing conservation tips on the other. Second, the design should be centered on the users and undergo iterative usability tests. A more detailed description of the literature-based requirements informing the design of EnergyLife is offered at the beginning of the paper. The way in which they are embodied in the features of the mobile interface, epitomized by its intuitive 3D carousel, is then described. Finally, the rationale and results of the first usability evaluation are reported, describing the responses to a satisfaction questionnaire and the types of breakdowns that occurred during the users’ interaction with the device. These results will guide the next development phase and the release of a new prototype.