Net Zero is the answer, but what was the question? How can we build and renovate Swiss buildings so that they sustain life and well-being of future generations? In this project, we want to assess current practices to build and renovate buildings, in order to highlight solutions which are technically and economically feasible. We will model existing buildings with different greenhouse gas accounting methodologies and consider various future scenarios in order to reach a robust comparison between buildings. In particular, we will look at built buildings using biobased and reused/recycled materials or building components as well as new advanced and alternative construction materials. The components of the different studied buildings will then be integrated in the building stock model done by F1.