This paper presents the experimental testing and field evaluation of the hygrothermal performances of stabilized Rammed Earth (RE) from material- to building-scale level. Different passive design strategies to improve the energy efficiency of RE structures are also discussed based on a validated building energy model implemented on EnergyPlus. The accuracy of the model was approved through a two-month monitoring period within a demonstrative building during the summer season. The study involved the fabrication and characterization of a RE unit using local soil stabilized with 5 wt% cement and 15 wt% lime. Laboratory tests were conducted to assess the mechanical, thermal and moisture-related properties of developed RE. The results demonstrated that the stabilized RE exhibited excellent hygrothermal properties, with a moisture buffering capacity value of 2.76 g/ m2%RH and a specific heat capacity of 983 J/kgK. Field observations confirmed the effective temperature and moisture regulation capabilities of rammed earth construction. Additionally, numerical findings indicated that the combination of wall thickness, night ventilation and a shading envelope can significantly reduce cooling energy demand by up to 31.8 %, decrease Indoor Overheating Hours (IOH) by up to 16.9 %, and mitigate indoor air temperature by approximately 5.15 degrees C and the peak indoor temperature by 2.6 degrees C during the hottest week of summer.