This paper presents a combined Life-Cycle Sustainability Assessment (LCSA) and Multi-Criteria Decision Analysis (MCDA) study on two off-grid houses in a rural village in Portugal to assess the sustainability of meeting electricity and heating needs in off-grid homes. The sustainability of meeting energy needs in the off-grid homes, compared to using the grid, was found to be dependent on the indicators under consideration, the technologies used in the homes, and household energy needs. We compared the current situation to four energy provisioning scenarios using Multi-Attribute Value Theory to rank alternatives based on their sustainability performance. The considered scenarios evaluated the impacts of extending and connecting the grid to the homes to allow for either: electricity consumption from the grid, or both consumption and injection of excess electricity generated to the grid. The results showed that meeting household electricity and heating needs in a sustainable way requires an analysis of the local context and available resources. Thus, a consideration of trade-offs is central to understanding the value of alternative possibilities for energy provisioning. This paper demonstrates that combining LCSA and MCDA procedures is useful for assessing sustainability impacts by incorporating decision maker’s preferences.