Three pathways towards carbon neutrality of existing single-family dwellings: what are the tipping points?

With the building sector being a substantial contributor to the European energy use and greenhouse gas emissions, there is a growing awareness of the need to renovate the existing building stock. Different renovation pathways to follow are possible in order to counter this need. However, it is unclear which one is the most preferable to achieve carbon neutrality of existing single-family dwellings by 2050. Several researchers already searched for decision-making methods that integrate Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) to assess both environmental impacts and financial costs. However, a practical application of these existing frameworks is lacking. This research project aims to provide insight and knowledge about which renovation scenarios are most optimal for different types of single-family dwellings. Therefore, a refined multi-criteria life cycle evaluation method is used to balance and weigh LCA and LCC. Three main scenarios are evaluated and compared: one-step deep energy renovation scenarios, step-by-step deep energy renovation scenarios and scenarios regarding demolition followed by new build. Moreover, tipping points are searched in the trade-off between these scenarios.