According to the IEA Global Status Report for Buildings and Construction 2019, one of the main industry sectors causing environmental impacts is the construction sector. Hence, construction materials from renewable resources are expected to have a large potential to decrease these impacts. In this study, a Life Cycle Assessment (LCA) was conducted for four different insulation materials from renewable feedstock: insulation made from pasture grass, seaweed, reed, and recycled jute fibres. Additionally, the effects on land use change were evaluated for pasture grass insulation using the LANCA® methodology. To put the LCA results in relation to those of non-renewable resources, a comparison of standardized LCA values for conventional insulation materials is presented. In general, the renewable insulation materials show fewer environmental impacts than their conventional counterparts. In particular, these materials have advantages regarding greenhouse gas emissions and their impact on climate change. Of the analyzed materials, seaweed showed the overall lowest emissions. It can be concluded that insulation materials from non-mineral, non-fossil, and non-wooden resources are still fairly niche in terms of market share, but they have extraordinary potential in decreasing the environmental impacts of construction ventures.