Integrating the flexibility of small-scale assets into the redispatch process is a necessary measure for the reliable operation of future energy systems with high shares of renewable energy, flexible loads and battery storages, especially at low voltage levels. Market-based procurement of redispatch flexibility from such assets is a useful complement to the existing process, enabling a scalable solution that reduces complexity for grid operators by decentralizing operations and pooling assets through aggregators. We present the novel flexibility model BASE for household-level assets that is tailored to this use case. The model provides fundamental features and principles, but the calculation method may differ for different asset types. This is demonstrated by detailing the calculation methods for battery storages and heat pumps. The model enables efficient local computation on edge hardware, and can be used to generate optimized aggregated redispatch offers in a flexibility market. Intelligent aggregation facilitates offers that leverage the heterogeneity of the asset pool, thereby conferring a substantially greater degree of flexibility compared to that achievable through individual flexibility offers. The conceptual extension to other types of flexible plants is planned for future research.