Life Cycle Environmental and Cost Analysis of Building Insulated with Hemp Fibre Compared to Alternative Conventional Insulations – a Swedish Case Study

Abstract

This study presents a comparative life cycle analysis (LCA) and life cycle costing (LCC) assessments of hemp fibre and conventional alternative insulations for the climate shell of a building. The conventional alternative insulations compared to the hemp fibre are cellulose and glass wool. The object of the analysis is a one-story single-family house, in Växjö, Sweden, and the lifetime of the house is set to 50 years. The LCA focuses on the Global Warming Potential (GWP) impact and the LCC during the lifetime of the different insulations for the building are calculated using the net present value method. The results show that the net GWP-impact for hemp fibre insulation is about 10 % lower and the cost is about 20 % higher than the conventional glass wool alternative. Furthermore, the analysis shows that cellulose insulation has slightly lower GWP-impact and nearly the same cost as the glass wool alternative. Sensitivity analyses regarding five different issues were performed and these show that: for cellulose coming from recycled paper, it contributed to less fossil emissions than non-recycled paper. If the data source for glass wool insulation is changed from environmental product declarations (EPD) to generic data, the greenhouse gas emissions increased. By replacing district heating system with geothermal heating system, fossil GWP-impacts also increased while the LCC analysis shows that operating costs is reduced. If the fuel is changed from diesel to electricity, fossil emissions are reduced over the life cycle of the building. If only part A1 – A5 is reported, as required for the Swedish climate declaration, the results point to the outcomes that glass wool insulation gives the least fossil GWP-impact while the hemp fibre gives the least net GWP-impact.