## 5 Conclusions  
This paper presents a comprehensive study on the integration of bio-based phase change materials (BioPCMs) into building envelopes, aimed at enhancing energy efficiency in residential buildings in Jordan and the city of Oradea in Romania. The key findings, arranged according to their importance, are as follows:  
* Incorporating BioPCMs led to a significant reduction in energy consumption, with a 34.38% decrease in heating and a 23.33% decrease in cooling energy compared to the baseline model at a melting point of 23 \({}^{\circ}\)C.
* The modeling and simulations revealed that BioPCMs significantly improved thermal performance, leading to more efficient heating and cooling in buildings.
* BioPCMs offer considerable environmental benefits, including non-toxicity, recyclability, reduced manufacturing emissions, and a notable reduction in greenhouse gas emissions, estimated at an annual decrease of 2382.31 kg of equivalent carbon dioxide.
* The BioPCM(r) M91/Q23 configuration demonstrated economic viability, with an estimated payback period of just four years.
* The simulation results showed the highest energy-saving rate in Amman (20.14%), followed by Irbid (19.78%), Aqaba (7.50%), and Oradea (5.64%).
* In moderate climates, like Amman and Irbid, where average temperatures align closely with the PCM's phase transition temperature of 23 \({}^{\circ}\)C, PCMs showed enhanced performance, resulting in greater thermal stability compared to very hot-dry climates like Aqaba and cold-wet climates like Oradea.
* The close alignment of average daily temperatures with the PCM's phase transition temperature in moderate climates led to decreased energy consumption by HVAC systems for maintaining indoor thermal comfort.
* Through all studied locations, the PCM-incorporated building models demonstrated a lower EUI compared to baseline models with conventional insulation, reflecting a substantial reduction in total end-use energy.  
This paper conclusively demonstrates that integrating phase change materials (PCMs) into building envelopes significantly reduces energy consumption. This key outcome underlines the potential of PCM technology as an effective solution for enhancing building energy efficiency, particularly in the context of climate change and the growing need for sustainable energy practices in the building sector.  
Conceptualization, M.J. and H.A.M.; data curation, M.J. and C.C.B.; formal analysis, H.A.M. and C.B.; funding acquisition, C.B.; investigation, M.J., H.A.M., C.C.B. and T.B.; methodology, M.J. and H.A.M.; project administration, C.B.; supervision, C.B.; validation, T.B.; visualization, C.C.B.; writing--original draft, M.J., H.A.M. and C.B.; writing--review and editing, C.C.B. and T.B. All authors have read and agreed to the published version of the manuscript.  
This research and APC were funded by the Romanian Ministry of National Education and Scientific Research, through National Council for Higher Education Funding, Contract No. CNFIS-FDI-2023-F-0426 with University of Oradea.  
Data Availability StatementData provided in this article are supported by experimental results and by the mentioned references.  
The authors would like to thank to the University of Oradea, Oradea, Romania, and the German Jordanian University, Amman, Jordan for the facilities and support provided.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.