Low- carbon design strategies for new residential buildings – lessons from architectural practice

This study presents the environmental life cycle assessment of four low carbon design strategies applied in Danish, architectural practice. The subject of analysis is a set of five buildings erected within the same constrictions in terms of floor area, energy performance and construction costs. The tested design strategies were: use of recycled materials, design for extended durability of components, adaptable design, and design for reduction of operational energy demand. The results of the five buildings are compared with a reference building (i.e. a typical, Danish single-family dwelling). Results show that the recycling/upcycling strategy is the most effective in reducing the embodied carbon. The use of structural wood in the same design furthermore points to the use of wood as a viable low-carbon strategy. In combination, these two strategies result in an approximate 40% saving of life cycle embodied carbon compared to the reference. Using durable materials yields up to 30% lower embodied carbon compared to the reference, whereas a design for adaptability results in 17% lower embodied carbon. However, these results are sensitive to the scenarios made for the service lives of materials and the implemented disassembly solutions. In a life cycle carbon perspective, the emissions from energy use prove to be of importance, although depending on the modelling approaches of the energy mix. With the shrinking, global carbon budgets in mind, there is justified reason to holistically optimize the design of new buildings by integrating various design aspects addressing the whole life cycle of the building.