Improving the energy performance of historic buildings with architectural and cultural values

The thermal performance of solid walls of historic buildings can be improved by external or internal insulation. External insulation is preferred from a technical perspective, but is often disregarded as many such buildings have architectural or cultural values leaving internal insulation as the only possible solution. As internal insulation is considered a risky way of improving the thermal performance from a moisture perspective, technically feasible solutions are needed. Further, other arguments than energy saving could convince a building owner to carry out internal insulation, e.g. improvement of thermal indoor climate.
The paper discusses different motivating factors for improving the thermal performance of solid walls in historic buildings with architectural and cultural values. It is argued that internal insulation, provided that it can be done without resulting in critical moisture conditions, is better than doing nothing in terms of reducing energy consumption and improving the thermal indoor climate, regardless of whether it is profitable for the building owner or not. Further, from a societal perspective, it is preferable to improve the thermal performance of existing buildings, instead of replacing them with new energy-efficient buildings, because of the architectural and cultural values that they possess. The underlying basis for this study is a 5-year research project, RIBuild, funded by the European Commission, running from 2015 to 2019.