Energy poverty is a growing societal challenge that puts the welfare of many European citizens at risk. Several different indicators have been developed to assess this phenomenon. This work aims to develop a novel high-resolution spatial scale composite index, focusing on space heating and cooling, to map energy-poor regions and identify hotspots for local action. The proposed index (EPVI) combines socio-economic indicators of the population (AIAM sub-index) with building’s characteristics and energy performance (EPG sub-index). The method was tested for all 3092 civil parishes of Portugal and could be potentially replicated at a European scale. Results show a higher prevalence of significative EPVIs in the inland region and the islands, particularly in rural civil parishes. Although cooling EPVIs are generally higher, heating may be a more significant issue in terms of energy demand and health hazards. Energy poverty vulnerability assessment at such a disaggregated regional scale could bridge the gap between common overall country analyses and local-scale initiatives targeting vulnerable households. The outcomes of this paper support national and local energy efficiency policies and instruments while fostering better assessments and enabling local actions to tackle this problem.