# Triple Validation of Calibrated Building Energy Models with Different Air Infiltration Values
## 5 Applicability, Limitations, and Further Research  
The novel method presented in this study is versatile and applicable to various building types and climates, provided that data on envelope material characteristics and local weather conditions are available. Although in situ weather data can enhance model accuracy, data from nearby weather stations remain a practical alternative, though with some potential limitations in precision. This study included 30 days of tracer gas tests, though prior research suggests that fewer decay days (e.g., 9 days [51]) may be sufficient for in situ infiltration models, offering flexibility in data requirements. Furthermore, the increased use of CO\({}_{2}\) sensors in commercial buildings since the COVID-19 pandemic supports model calibration with minimal additional equipment, as long as indoor temperature data are also available. This approach may be more easily implemented in commercial settings with building management systems (BMS) but may present challenges in residential contexts unless the project is part of a dedicated research study. In cases of missing data, machine learning algorithms may offer valuable solutions to improve model reliability. While the controlled environment and extensive monitoring available in this case study allowed for precise data collection and accurate model calibration, the specific characteristics of this building may limit the universal applicability of the results. Factors such as building orientation, materials, and the unique microclimate of the study area could influence outcomes differently in other contexts. Although the specific results may not be universally generalizable or directly applied to other case studies with similar characteristics, the general trends observed in the calibrated models, particularly the advantages of incorporating empirical air infiltration data, are expected to be consistent across different building typologies. Moreover, the insights gained from this case contribute to methodologies for conducting triple validation, providing a foundation for future research on the impact of air leakage in various building contexts. Additionally, because this study focused on a single zone, further research is needed to assess its applicability to multi-zone configurations. We acknowledge that conducting tracer gas tests is impractical. Therefore, alternative methods for estimating and empirically validating air leakage through decay should also be explored, including utilizing CO2 metabolic data. Conceptualization, G.B.P., J.B.E.T. and C.F.B. ; methodology, G.B.P., J.B.E.T. and C.F.B. ; software, G.B.P., J.B.E.T. and C.F.B. ; validation, G.B.P., J.B.E.T. and C.F.B. ; investigation, G.B.P., J.B.E.T. and C.F.B. ; resources, G.B.P., J.B.E.T. and C.F.B. ; writing-original draft preparation, G.B.P., J.B.E.T. and C.F.B. ; writing-review and editing, G.B.P., J.B.E.T. and C.F.B. ; supervision, J.B.E.T. and C.F.B. ; project administration, J.B.E.T. and C.F.B. ; funding acquisition, J.B.E.T. and C.F.B. All authors have read and agreed to the published version of the manuscript. The author, [PERSON], has received funding from a Ph.D. scholarship program called \"Asociacion de Amigos de la Universidad de Navarra\" of the University of Navarra, Spain. Not applicable. The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author. The authors declare that there are no conflicts of interest.