This toolkit is a guide for the launch of a One Stop Shop on energy retrofitting. It clearly explains how to start an energy retrofitting project and identifies the main challenges and success factors, based on the experience of RenoWatt. RenoWatt, an energetic One Stop Shop, is a pilot project launched in Wallonia, Belgium. This document aims to share RenoWatt's best practices and to facilitate replication of the model elsewhere in Europe and on a larger scale. The toolkit addresses practical issues and offers step-by-step guidance for private and public actors. This document is meant to evolve as the pilot project RenoWatt is developing.