Electricity production emits carbon dioxide and other gases into the atmosphere, adversely influences global climate change, depletes limited natural resources, and negatively impacts the lives of those who live near power plants. We designed a residential electricity monitoring and feedback system called WattBot, that allows users to track their home energy usage and encourages them to reduce consumption. Our solution is an application for the Apple iPhone and iPod touch that receives data from a wireless hub, allowing users to view, compare and analyze their electricity usage over time. Keywords Sustainability, energy use, interaction design, persuasive computing, visualization, feedback ACM Classification Keywords H.5.m. Information interfaces and presentation (e.g., HCI): Miscellaneous.