The central-heating paradigm has always functioned in tandem with clothing, which for the most part conserves body heat through insulation. This project tips the balance toward on-body solutions, using active on-body heating in conjunction with insulation and passive thermal protection to heat the individual human body rather than the entire environment. The motivating hypothesis is that if heat can be delivered effectively to the individual?s body, then the need to heat large (and often empty) spaces will be significantly reduced. However, if on-body heating technologies are ever to become widely accepted, they must be comfortable and wearable in everyday environments, while also keeping the body as comfortable as central heating currently does. This is a challenge because the body?s perception of thermal comfort is strongly influenced by the temperature of the face and hands, areas where wearable technologies can be obstructive or socially awkward to wear in everyday situations. This project will develop comfortable, socially subtle wearable technologies that both preserve body heat and deliver additional heat to these key body areas, and evaluate their ability to maintain thermal comfort and reduce the comfortable ambient temperature in heated spaces. If successful, such technologies have the potential to offer both large-scale energy savings, but also allow for individualized thermal comfort, with each occupant selecting their optimal temperature. Because of the interdisciplinary nature of the problem, this project will contribute to the education of students from several contributing disciplines, and will introduce project and research opportunities to students in undergraduate and graduate coursework. The research proposed here focuses on the development and thermal chamber evaluation of comfortable, socially appropriate methods of delivering heating to these sensitive areas. Second, the effect of these technologies on acceptable ambient temperatures (and the resulting energy savings) are evaluated in a field trial. Finally, the boundaries of the concept are extended in early-stage exploration of persuasive interfaces through on-body temperature modulation. The intellectual merit of the proposal lies in its contributions to developing effective sensor/actuator technologies for modulating individual micro-climate in conjunction with IoT and ambient devices, and establishing the boundaries of the relative influence of micro-climate on human comfort (with corresponding effects on energy consumption). The broader impacts of the proposed research most directly include the potential for a large savings in the energy costs spent on heating in cold climates. The education plan integrated into this research will contribute to interdisciplinarity and diversity in engineering.