Historic building energy audit and retrofit simulation with hemp-lime plaster-A case study

Hemp-lime composite is a natural material, which is being increasingly used and studied in the construction sector, thanks to its recyclability, hygrothermal comfort and healthiness features. The aim of this paper is to test the benefits in terms of energy efficiency achieved through the use of hemp-lime composite as insulation in a possible refurbishment intervention. With the aim of extending the knowledge about the benefits achieved through from the integration of this natural material into construction production process, a real building in south of Italy was selected and a substitution of the standard gypsum-lime plaster with a hemp-lime one was simulated by means of a specific software (Termus® by Acca Sotware, Bagnoli Irpino, Italy), serving for the assessment of the energy performance. Case study analysis highlighted the good thermal insulation properties of hemp-based plaster, allowing thermal dispersion to decrease in the winter season and improve the summer performance of the walls by approximately 20% compared to traditional plaster. This results in a one-level improvement of the building in energy classification according to Italian regulation.