The sustainable implementation of demand-side management (DSM) for district heating and cooling (DHC) is often limited because of DHC's complexity and the requirements to involved stakeholders. The purpose of this study is to define the design principles of an organizational system for implementing economically sustainable DSM innovations in DHC. A design science approach is used to qualitatively analyze a real-life DSM implementation and decontextualize the organizational design toward more widely applicable principles. Combining empirical material gathered from ten interviews, document analysis and six months of participant observations with recent theoretical development on innovation ecosystems, we formulate a conceptual process framework that can facilitate the development and operation of an economically sustainable DSM solution. The process framework features five interlinked design principles. The findings contribute to the literature on multiorganizational systems and the implementation of technological innovations in the building and energy sectors.