Efficient heating, ventilation, and air conditioning (HVAC) systems play a crucial role in preserving ideal indoor air quality by utilizing modern energy-saving techniques while ensuring environmental integrity. This paper introduces a novel HVAC system in cold climates to meet thermal comfort with lower energy use than traditional systems. The smart HVAC unit is driven by a naturally driven free heating and cooling system interacting with the district heating network. At the heart of this concept is using earth as a seasonal thermal reservoir to store and generate energy through 25 boreholes equipped with several smart controllers to meet the heating and cooling demands of an office building in Uppsala, Sweden. TRNSYS analyzes the system's performance from the techno-economic aspects, applying thermodynamic rules and lifecycle cost assessment. The results show that the air handling unit can meet more than 50% of heating and cooling demands throughout the year thanks to efficient waste heat recovery via the proposed intelligent integration. According to the results, despite high investment costs of around 399,000 $, the proposed system has a promising payback period of fewer than ten years, demonstrating the role of smart HVAC design through a clever control framework. Finally, the results show that considerably lower primary energy is used by recovering the annual free heating and cooling of 313 MWh from the ground via boreholes, highlighting the effectiveness of utilizing the earth's stable temperatures for thermal control.