This study presents an area-based framework for incorporating one-dimensional (1D) and twodimensional (2D) thermal bridges into monthly energy-demand calculations. Traditional single correction factors do not capture variations in thermal-bridge geometry or construction details, leading to inaccuracies in heat-loss estimates. The proposed method quantifies 1D thermal bridges as area-normalized transmittance increments (ΔU1D) and 2D thermal bridges as ψ·l/A, enabling consistent evaluation of thermal-bridge effects across walls, roofs, and floors. A 3D model–based automatic extraction of junction lengths further improves computational accuracy and practical applicability. The framework aligns with ISO 52016-1 procedures and is expected to support future developments in automated and 3D Model-integrated thermal-bridge assessment.