Cost-benefit analysis of on-site airtightness commissioning: The case for a digital evidence-based approach

초록

Building enclosure commissioning (BECx) is increasingly promoted to close the gap between design intent and as-built performance, yet empirical evidence on its cost-benefit profile remains limited. This study evaluates an on-site, expert-led BECx delivery model targeting airtightness in retrofit projects through a comparative case study of eight public buildings. The BECx-attributable performance uplifts across the four experimental sites averaged 1.14 ACH50 (0.73 to 2.10 ACH50). The incremental direct cost was 18,841 USD; the investment was not recovered through operational energy-cost savings alone under the base-case and conservative-case assumptions, and even the optimistic-case discounted payback estimate was 88.8 years. These results indicate that on-site BECx can be effective in practice but is difficult to justify as a routine delivery model. To address this tension, we propose digital evidence-based commissioning (DE-Cx) as a prospective conceptual framework, informed by an electronic health record (EHR)-enabled preventive-care analogy, that uses standardized evidence capture and acceptance records to preserve auditable performance assurance while reducing dependence on continuous on-site specialist presence. A prospective scenario-based cost analysis suggests that DE-Cx could reduce the incremental commissioning cost by 57.3% and shorten the optimistic-case discounted payback estimate to 45.4 years, although full cost recovery remains unachieved under the base-case and conservative-case assumptions. The empirical results and the cost structure motivate a shift from labor-intensive, site-bound airtightness commissioning toward preventive, evidence-driven workflows that can verify enclosure performance at scale, and call for a broader assessment of commissioning benefits beyond operational energy savings.

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