This dataset presents operational energy data from forty residential buildings constructed between 1980 and 2020 in Cuenca, a city in the Andean region of Ecuador. It includes energy consumption data related to heating, cooling, lighting, electrical appliances, domestic hot water and cooking. Ten sample houses from each decade were selected, representing typical construction practices of their respective periods. The study follows three main stages: (1) Analysis of operational energy consumption, showcasing the evolution of energy use across four decades; (2) Simulation and validation, where energy simulations and calculations are performed for each sample, followed by a validation process using in-situ measurements compared with simulated results; and (3) Data curation, where climate data is compiled and updated for further analysis. This dataset includes files and figures that enhance comprehension and support further research on energy efficiency, sustainable building design, and energy policy development in regions with moderate climates. It also enables comparisons with datasets from other geographic regions, contributing to a broader understanding of energy demand patterns in residential buildings.