This short paper introduces Energy in Schools, an interactive platform designed to improve energy efficiency in UK schools through a combination of environmental measurement and behavioural change. Uniquely, Energy in Schools is designed to empower all the stakeholders within a school, including children, teachers and leadership groups to reduce their energy costs and carbon emissions. The paper reports on the motivation and design of the platform, a discussion on how interactive materials and educational activities were developed to raise awareness and understanding of energy and the climate emergency, how children led activities were used to instrument and analyses energy use via child friendly Internet of Things technologies. Finally, an analysis of its success in encouraging behavioural change through the qualitative and quantitative evaluation of a live deployment across 20 schools is presented. Overall, it was observed that encouraging multiple stakeholders to work together interactively can decrease energy consumption in the majority of schools by over 5%.