An aging building stock and low-efficiency heating, ventilation and air conditioning (HVAC) systems may be preventing the adequate energy performance (EP) of Portuguese dwellings. This study aims to estimate and analyze the EP gap of the occupied main residence Portuguese residential dwelling stock, for thermal comfort attainment, at high geographical resolution scale, i.e. for every civil parish.

A building typology approach was applied to estimate the heating and cooling (H&C) theoretical final energy consumption (TFEC) for thermal comfort. An energy consumption statistics-based approach was used to estimate the H&C real final energy consumption (RFEC). The EP gap is the percentual difference between the TFEC and RFEC. Three scenarios were tested, looking deeper into southern European space H&C patterns, considering varied conditioned areas and occupancy schedules.

This study provides a methodological framework for zooming in the assessment of the dwelling stock EP for a whole country, allowing for a comparative analysis between regions, as the different regional EP gap drivers are identified. For nominal conditions, every civil parish has an EP gap higher than 60%, for both H&C, related to poor energy efficiency of the building stock and low H&C energy consumptions. The scenarios demonstrated a bridging of several civil parishes’ EP gap, possibly resulting from temporal space climatization patterns. High remaining EP gaps suggest that the civil parishes in the north and center inland regions are the most vulnerable in the winter and summer seasons, potentially due to significant energy poverty levels.