This study introduces a novel space feasibility assessment process and evaluates its effectiveness through a comparative analysis with a conventional manual process. The proposed method is designed to enhance spatial comprehension and integrate building performance analysis, thereby supporting budgetary considerations during the early design phase. By providing a more intuitive and interactive environment, the system enables stakeholders—such as building owners—to communicate their spatial requirements to architects and professionals more clearly and efficiently. To validate the effectiveness of the proposed approach, participants completed two distinct scenarios: (1) a manual space feasibility assessment, and (2) a system-supported space feasibility assessment utilizing the proposed method. Participant performance was measured in terms of speed and accuracy in each scenario. Additionally, a user satisfaction survey was conducted to evaluate the usability of the system’s functionality. The experimental results provide an empirical basis for comparing the proposed process with the manual approach. Findings demonstrate that the proposed process enables more efficient and accurate space feasibility assessments, thereby validating its effectiveness as a user-centered decision-support tool during early-stage architectural planning.