Internal insulation – a preliminary assessment tool based on probabilistic simulations

Historic buildings contribute heavily to the energy consumption of the European building stock, and internal insulation offers a possibility to improve energy performance and indoor thermal comfort, without compromising the buildings’ architectural appearance. However, due to the complexity and many potential risks and uncertainties less experienced planners and building owners need a
preliminary assessment tool and simple, practical guidance in a specific situation. This paper presents and discusses such a tool developed as part of RIBuild (www.ribuild.eu); the content, preconditions and limitations.
User input encompasses specific location and orientation of a building, and wall thickness and type, by using checkmarks and sliders. In each case, the tool delivers a list of solutions selected from a database of pre‐calculated simulations made in the hygrothermal simulation tool DELPHIN with Quasi‐Monte Carlo based repetitions of simulations; a probabilistic assessment. The user can prioritize solutions based on e.g. risk of mould growth or maximum thickness of insulation. The output describes the heat loss through 1 m² wall with and without internal insulation, as well as risk of mould growth behind the insulation and algae growth at the façade. An improvement of the reliability of the tool requires more simulations and the inclusion of other failure mechanisms than mould and algae growth.