Enhancing Risk Assessment in Net Zero Energy Building Design through the Integration of Decision-Making Frameworks and Failure Modes Analysis

• Comprehensive identifying potential failures in NZEB design. • Propose strategies to enhance the performance and sustainability of NZEB through innovative design and construction. • Proposing the group decision-making framework based on fuzzy sets and fuzzy ZE-numbers. • Comparison of the results obtained by the proposed approach with other approaches. Failures in Net Zero Energy Buildings (NZEBs) can undermine energy efficiency and environmental sustainability, often increasing reliance on conventional energy sources and elevating carbon emissions. Such failures impair system operation, reduce performance efficiency, and compromise long-term economic benefits. To uncover root causes and enhance NZEB performance, effective failure analysis is essential. Traditionally, Failure Mode and Effects Analysis (FMEA) has been the standard tool for identifying and ranking potential faults in design and operation. This study proposes an extended FMEA based on ZE-number that considers group reliability, and also by incorporating cost alongside severity, occurrence, and detection, it improves the Risk Priority Number (RPN), thereby providing a more comprehensive and effective risk assessment. The proposed framework proceeds in three stages: (i) calculation of the extended RPN, (ii) weighting of sixteen evaluation criteria using Step-Wise Weight Assessment Ratio Analysis under Fuzzy ZE numbers (ZE-SWARA), and (iii) ranking of failure modes using the Combined Compromise Solution under Fuzzy ZE numbers (ZE-COCOSO). Compared with the traditional FMEA, the proposed approach yields greater discrimination among failure modes; for example, poor air sealing and insufficient insulation are prioritized significantly higher once cost impacts are considered. The results identify poor air sealing as the most critical issue, followed by suboptimal insulation practices and inadequate sizing of renewable energy systems. These findings highlight the added value of integrating economic factors and fuzzy multi-criteria decision-making into failure analysis. The proposed framework offers practical guidance for designers and engineers, supporting more reliable decision-making, preventive strategies, and resource allocation in NZEB projects.