To upgrade or not to upgrade: Issues for consideration upgrading old apartment buildings

This paper identifies the key indicators that owners need to take into account in order to choose the most affordable extent of upgrading of a typical post-1945 building. The exterior look of the building is not to be changed. Indicators include measures, risk assessment related to the changes in the building physics provided by upgrading measures as well as costs and savings needed to achieve different levels of energy savings. The extent of “Upgrade level 2”, and “Upgrade level 1” defined in the Danish Building Regulations from 2015 are addressed and seen to be reachable. However, it is recommended not to carry out upgrading of a building by adding thermal insulation to the internal side of the external wall. The upgrading measures are seen to result in constructions less robust to moisture than before upgrading and costs that cannot be paid back by energy savings. Analysing tools like Be15, HEAT2 and WUFI Light were used for the investigations. Finally, the owner is recommended to upgrade by adding thermal insulation on to the exterior side of the exterior walls, which will indeed change the look of the building.