The Role of Geometric Simplification in Building Energy Simulation: A Systematic Review with Insights on Historic Buildings

Energy simulation software has become a widely adopted tool in both professional and academic fields, supporting tasks such as renovation evaluation, performance estimation, and energy certification. Despite its extensive use, there are still challenges in the modeling process that need further investigation, as they can affect the accuracy of the simulation results. Many of these issues are related to the geometric simplification performed during the modeling phase. In fact, energy modeling software requires a simplification process of the real building, which inevitably leads to a loss of accuracy. This issue is especially critical in historic buildings, where complex geometries increase the risk of error and require more advanced modeling expertise than new buildings. Moreover, although many previous studies have addressed the accuracy of building energy simulations, few studies have systematically addressed the role of geometric simplification in this context. The analyzed literature is not exclusively related to historic buildings but also considers new and generic constructions, as many modeling issues are common among these categories. However, historic buildings often have greater geometric complexity and therefore provide an opportunity to analyze various modeling challenges. In this regard, this research presents a systematic review of geometric model simplification strategies used in building energy simulation, studies their impact on the results, and tries to define an appropriate procedure for energy modeling to reduce the performance gap. Furthermore, the results indicate that future research is needed to develop well-documented and accurate geometric model simplification methods capable of assisting designers with their building energy simulation needs.