The research from the Pusan National University in South Korea introduces an attachable solar collector (PVT–ASC) for Photovoltaic–Thermal module designed for zero-energy buildings. Overcoming high initial costs, the on-site constructed PVT–ASC achieves 41% thermal efficiency. Computational fluid dynamics and cost analyses affirm commercial viability, showing a 39% cost reduction and 28% CO2 emission decrease compared to existing products.