Field-Informed EnergyPlus Assessment of an Earthbag Building in Nepal: Comparative Analysis with Brick and RCC Construction

Earthbag Construction offers potential advantages for passive thermal performance, yet its effectiveness relative to conventional building systems remains insufficiently investigated under Kathmandu’s climatic conditions. This study compares the thermal performance of an existing earthbag building with fired-clay brick masonry and an approximated reinforced-concrete (RCC) frame with brick infill using OpenStudio and EnergyPlus. Free-running and conditioned simulations assessed indoor operative temperatures, overheating exposure, and annual sensible heating and cooling requirements, supplemented by a 24-hour field verification using measured indoor and outdoor conditions. The earthbag model required 4,815.6 kWh of annual heating and 867.4 kWh of cooling, compared with 4,874.5/978.5 kWh for brick and 4,937.9/949.9 kWh for RCC, respectively. Annual overheating exposure was lowest for earthbag at 4,103 roomhours, compared with 4,640 for brick and 4,512 for RCC, while field verification yielded a mean absolute error of 0.87 °C and root-mean-square error of 1.17 °C. The findings demonstrate lower simulated cooling demand and overheating exposure for the earthbag configuration, although uncertainties in material properties, simplified RCC representation, and short-term field observations limit broader generalization.