Aligned with Denmark’s growing smart energy networks encompassing district heating and electricity grids and in harmony with the country’s ambitious energy and environmental objectives, this study aims to elevate the investigation from individual buildings to consider districts and cities. In pursuit of this objective, a case study of an Odense district in Denmark was considered for modeling, simulation, and energy performance improvement. The selected residential area was modeled using City Energy Analyst, an open-source urban scale modeling tool, accounting for different building attributes as well as the particulars of energy networks and supply systems. The validation of a baseline scenario is predicated upon real-world data collected on-site to serve as the benchmark for exploring and evaluating various scenarios and measures for enhancing energy efficiency. Consequentially, eight distinct energy enhancement packages were designed, modeled, and simulated individually. The results were analyzed, and it was shown that an energy improvement package consisting of retrofitting buildings’ constructions, indoor thermal comfort setpoint management, heating system upgrade, photovoltaic-thermal unit installation, and heat pump integration, along with a seasonal energy storage system, is capable of enhancing the overall energy efficiency quotient of the area, establishing a positive energy district with an excess in heat and electricity production.