The European Union’s ambitious objective of decarbonizing its building stock is a crucial and multifaceted undertaking aimed at achieving a carbon-neutral European society. To meet this challenge, it is imperative to adopt highly insulated building envelopes, efficient HVAC systems, renewable energy technologies, and to implement the reuse and recycling of resources and materials. In this study, we demonstrate an innovative apartment building renovation concept and compare results with nonrenovated building. The building envelope is insulated with prefabricated insulation elements to improve indoor thermal comfort and drastically decrease energy use for heating. Centralized mechanical balanced ventilation with heat recovery ensures indoor air quality. Supply ducts are integrated into the prefabricated facade insulation elements. Old chimneys were air-tightened and are now used for exhaust airflow. After undergoing a deep renovation, the Energy Performance Value was measured at 92 kWh/(m2a), indicating that the building now meets the requirements for a nearly Zero Energy Building (nZEB). After the renovation, the electricity produced by the PV panels on the roof, sold to the electricity grid of the Pilot 1 building, allowed it to cover the costs of servicing the renovation loan, significantly reducing the owners’ expenses. By utilizing on-site storage options, such as batteries, it is possible to better align the times when electricity needs are met with on-site production.