Assessment of the heat loss coefficient of a renovated historical dwelling using a co-heating test

Twelve quasi-identical almshouses with an architectural-historic value were reno-vated, because of their high energy use, poor indoor comfort and numerous moisture problems. Aerogel plaster was applied for the hygrothermal upgrade of the uninsulated brick walls, while limiting the reduction of living space in these very small houses and keeping the monumental character of the facades in their original state. Several quality assurance tests were executed to evaluate the quality of the renovation of the building envelope and to compare the results with the initial theoretical design calculations. It appeared that the existing materials performed considerably better than the assumed conservative default values. On the other hand, the newly installed insulation materials performed somewhat less than declared, for example due to on-site processing. This resulted in a strong overestimation of the improvement in thermal performance by the renovation works. Field measurements of the existing situation can help to close this gap.