Replacing windows in heritage buildings – reasons and regulations
It's not easy to install new windows in an old building. House owners cannot simply ignore heritage conservation and install new windows. If you make unapproved changes to historic buildings you could face high financial penalties and be forced to undo all the renovation work at your own expense. This includes heritage-protected windows. In other words, you cannot simply ignore heritage conservation. On the contrary. To find a solution and a balance between statutory regulations for heritage conservation and new windows or other necessary renovations it is important to work together with the local authorities.
The German Buildings Energy Act (Gebäudeenergiegesetz, GEG
) specifies the U-values
for a building; in other words, how much heat is permitted to escape outdoors (measured in watts) per square metre. For residential buildings, the regulations regarding tightness and thermal insulation are much more stringent than for buildings that are generally heated less and are used only at certain times in the year.
On the other hand, heritage conservation demands that renovation work preserves the historic character of the building. Ultimately, what this looks like – and this includes heritage conservation and new windows – is at the respective authority's discretion in the respective state. But it also depends on the individual building.
In some cases, only certain elements of a building are protected. Theoretically, heritage conservation could rule out installation of new windows if windows that are worth preserving from a historic aspect are present and are not allowed to be replaced. Some buildings are subject in their entirety to what is known as the protection and preservation of building groups. In these cases, you have to consider alternatives because heritage conservation and new windows are mutually exclusive. It is important to obtain information about the condition and heritage conservation status of a building in advance in order to avoid a clash between heritage conservation and new windows.