This study aims to forecast energy service demand (ESD) for residential buildings in Portugal up to 2050 using a bottom-up approach. The results suggest that ESD, particularly for cooling and lighting, will continue to increase due to a rise in comfort levels and equipment ownership and use. While final energy demand (FE) is projected to grow at a slower rate (0.1%/year) compared to ESD (1.3%/year), some end-uses may see a decrease in FE despite an increase in ESD. The study emphasizes the importance of considering energy services rather than just final energy when making projections, as it allows for a more comprehensive understanding of end-users' needs. The methodology involves the computation of a reference scenario (REF) and a sensitivity analysis of selected parameters to assess their impact on ESD. The study concludes that technology plays a significant role in some end-uses, and policy should focus on drivers behind heating and other electric appliances ESD.