While external wall insulation technologies are well proven, the installation supply chain is best suited to large social housing estates. Private homes are more diverse and more costly to insulate. Co-operating to Retrofit will combine the mutual co-operative business model, proven community engagement and social marketing principles, and innovative technological tools in a pilot project to roll out external wall insulation to private homes at a minimised cost – working with local community groups and local SME installers to recycle cash through the local economy. The project is designed to be expandable and replicable in a variety of community and neighbourhood settings. The pilot incorporates a varied demographic and will capture data and case studies that will act as exemplars, and a friendly internet presence will help to disseminate the approach. The consortium includes the Energy Saving Co-operative, Permarock Products, RetrofitWorks, University of Loughborough, Energence, Owl (2 Save Energy) and Rural Community Council (Leicestershire and Rutland) with local community groups.