<p>Hemp concrete is one of the greenest building materials available on the market. It demonstrates excellent thermal insulation properties, which have been confirmed by a number of tests. The paper presents the properties of composites containing hemp shive and traditionally used construction materials such as cement and lime. The paper also indicates the possibility of using fluidal fly ash as a component of hemp concrete. Fluidal fly ash is considered as waste from the coal combustion process in the energy sector, so its reuse will help reduce the scale of the problem of landfilling. The production of hemp shives and fluidal fly ash composites as durable materials with good insulating properties may contribute to increasing the environmental performance of the construction industry in the future. Hemp concrete makes it possible to construct walls without the need for additional insulation. The authors proposed three different binder compositions and compared their properties as insulating materials. A comparative analysis of the building's energy demand was performed. Obtained results allowed to assess the energy demand of a house made using hemp concrete technology at the level of EK = 22.94 kWh/m²∙year.</p> Graphical abstract <p></p>