This talk will introduce my 2022-2023 Royal Academy of Engineering (RAEng) Leverhulme Trust Research Fellowship (LTRF) project focusing on the front-end of DTs in buildings to design Digital Twins (DT) system requirements for Net-Zero, safeguarding people that rely on critical infrastructure to safely survive and maintain good a quality of life in a diverse society. Despite common misconceptions, DT are not one-size-fits-all solutions based on Building Information Modelling (BIM) and three-dimensional representation but vary depending on input sources and output goals, designed for specific purposes, e.g., energy use, consumption/user behaviour, weather, asset resilience monitoring. The talk will introduce the initial preliminary findings on the pathway through which DTs can support the Net Zero vision based on data analysis of interviews and surveys with more than 50 experts.