To evaluate the impact of residential demand-side changes on the energy system, EPRI has developed the Stochastic Behavior-based Load Simulator (LoadSim). This bottom-up modeling framework combines models of occupant behavior with detailed characterizations of major residential end-uses and their interactions with customers and the external environment. As a result, the contribution of each end-use toward the overall aggregate demand of the residential sector can be identified at the individual household level. This effort aims to extend the existing framework in several ways. First, by developing a more complete representation of a home’s thermal envelope to characterize additional building typologies. Second, by integrating more recent electric vehicle adoption and charging trends in response to rapidly changing market conditions. And third, by developing additional models for rooftop photovoltaics, battery energy storage, and demand flexibility. In addition to expanding the capabilities of this framework, a validation and benchmarking exercise is undertaken against established building energy modeling protocols and annual energy consumption surveys. Finally, to demonstrate the potential applications of LoadSim, a variety of modeling use-cases are presented.