Predicting annual heating energy use using BIM: A simplified method for early design phase

Building information modeling (BIM) and building energy modeling (BEM) are two key tools to make the transition to net-zero energy buildings (NZEB). However, a recent literature review indicated that the conversion from BIM to BEM is currently dysfunctional, due to limitations regarding competencies, processes, and technology. In this article, a case study is presented to show how the information in the BIM model can be used to calculate the annual heating energy use (kWh/m², year) using the simple degree-day method and extracting building envelope surfaces, heated floor area, and heated volume in the BIM model. The proposed method is for very early design phase (EDP) when architects are starting to determine the general building shape, window sizes, etc. This case study is a residential building called Eskilshem, located in Södermanland, Sweden (latitude 59.4^◦ N, longitude 16.5^◦ E) designed by White arkitekter in 2020. This article presents the workflow and equations embedded in BIM to obtain annual heat energy demand at EDP.