## 5 Conclusions  
This study used integral-monolithic structural insulation fibre-reinforced LWAC (without additional insulation) as building envelope material for high-rise residential buildings in tropical hot-humid and Mediterranean climates. The major drawback of structural LWAC is its brittleness behaviour and the use of fibres can mitigate this issue. Adding fibres to the LWAC mixture affects its thermal properties. In this study, the thermal properties of LECA-LWAC reinforced with different doses of steel (ST) and polypropylene (PP) fibres in mono and hybrid forms were measured and energy consumption in a high-rise residential building constructed with these types of LWAC was calculated using a simulation program. The energy consumption in the building was compared with NWC and conventional brick walls together with the building orientation in diverse climatic regions of the world. The following conclusions can be drawn from the results of the data analysis.  
1. HST0.75 + PP0.1 has the most efficient EUI performance and cost savings for Putrajaya at 3.19% and 4.04%, respectively, as compared with NWC.
2. HST0.75 + PP0.3 has the most efficient EUI performance and cost savings for Makkah at 5.86% and 6.46%, respectively, as compared with NWC.
3. HST0.75 + PP0.3 has the most efficient EUI performance and cost savings for Istanbul at 4.45% and 5.09%, respectively, as compared with NWC.
4. PP0.3 has the most efficient EUI performance and cost savings for Lillhardal at 12.79% and 12.29%, respectively, as compared with NWC.
5. The energy and cost savings of the fibre-reinforced envelope material is in the following order based from high to low: HST0.75 + PP hybrid \(>\) mono PP \(>\) ST + PP0.2 hybrid \(>\) mono ST \(>\) NWC \(>\) Brick for Putrajaya, Makkah and Istanbul, while Lillhardal is mono PP \(>\) HST0.75 + PP hybrid \(>\) ST + PP0.2 hybrid \(>\) mono ST \(>\) NWC \(>\) Brick.
6. The use of the integral monolithic structural-insulation fibre-reinforced LWAC in tropical (Putrajaya, Malaysia) and Mediterranean (Istanbul, Turkey) climates meets the certified-EUI requirements of less than 150 kW\(\cdot\)h\(\cdot\)m\({}^{-2}\)-year\({}^{-1}\) without additional insulation or double-glazing window/shade.
7. Extreme climatic conditions of sub-arctic (Lillhardal, Sweden) and semi-arid desert climates (Makkah, Saudi Arabia) require additional insulation material with double-glazing windows to meet the LEED-certified green building requirements.
8. All traditional construction materials, such as NWC, sand-cement brick and clay brick, fail to qualify for the certified-EUI requirements.
9. The energy-saving measure is driven largely by using fibre-reinforced LECA-LWAC as a building envelope material rather than building orientation.  
**Author Contributions:** Conceptualization, Z.C.M. and P.S.; data curation, Z.C.M.; formal analysis, Z.C.M. and P.S.; funding acquisition, Z.C.M., P.S., S.B. and S.M.E.S.; investigation, Z.C.M. and P.S.; methodology, Z.C.M., P.S., N.B.M., S.B. and A.Z.; project administration, Z.C.M. and P.S.; supervision, P.S. and N.B.M.; validation, Z.C.M., visualization, Z.C.M., P.S., S.M.E.S., and S.B.; writing--original draft, Z.C.M.; writing--review and editing, Z.C.M., P.S., N.B.M., S.M.E.S., S.B. and A.Z. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was financially supported by the University of Malaya Postgraduate Research Grant (IPPP), Grant No. PG217-2016A and YCU Grant No. 201901001 YCU/11.  
**Acknowledgments:** We greatly acknowledge the support of the University of Malaya and National Energy University in using the laboratory facilities for the experimental works.  
**Conflicts of Interest:** The authors declare no conflict of interest.