Platforms facilitate the participation of households and their energy assets in the energy system. Platform services are considered attractive for households if the energy cost savings exceed the transaction cost of the service. We conceptualize different platform architecture, quantify their transaction cost and compare it to potential energy cost savings from the literature. The design of its communication infrastructure especially influences the attractiveness of the platform architecture for two reasons. First, its other cost, particularly the platform core, accounts only for a minor cost share. Second, the grey and scientific literature discusses multiple communication infrastructure designs referring to smart metering. For the German case, two key design options, the certified and regulated advanced metering infrastructure and the agile Internet of Things based communication are combined into a third option to create a fully functional and certified infrastructure. This is the most attractive option for households deploying multiple flexibility sources or one large and predominantly controllable one (such as a heat pump). @en