Windows and heritage conservation: Rules, regulations, PVC windows

If a protected building is to be actively used or reused, at first glance, it would seem that heritage conservation and new windows are incompatible. Whether to renovate windows in an old building or to replace them with new heritage windows in order to implement energy saving measures and give an old building a fresh look can be a difficult choice to make. You have to overcome numerous statutory obstacles in order to combine heritage conservation and new windows. In some cases you may not be able to meet all the requirements and will have to look for alternatives for your renovation project. We will explain the reasons for installing new windows despite heritage conservation, what you have to consider in the approval process and how to proceed in detail.  

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.   

Window renewal versus renovation – what’s practical with regard to heritage conservation

If you want to renew or renovate heritage windows, you have to fulfil numerous conditions. All renovations have to be approved. Accordingly, replacing heritage windows or combining heritage conservation and new windows is not really viable. Old windows have to remain as much as possible, while, at the same time, they have to satisfy modern climate protection regulations. A professional, specialist planner can help house owners record all the damage on old windows, carry out an energy analysis and, based on this, draw up a renovation plan that is required for approval. If the responsible heritage conservation authority approves the plan, you can start renovating.    
If the authority allows a little more leeway with regard to heritage conservation and new windows, it is worthwhile considering heritage timber or PVC windows. Particularly the latter are much less expensive and can be convincingly similar to the original windows. Nevertheless, they can reduce the value of a building. Alternatives include outer windows, an additional window sash inside or renewing the gasket to avoid problems with heritage conservation due to new windows.  

PVC windows and heritage conservation – advantages, disadvantages and regulations

Even if it is difficult to install new windows due to heritage conservation, heritage PVC windows are often less expensive because they are mass-produced on an industrial scale. If they are fitted with a wood decorative tape, from a distance they are almost indistinguishable from the original. The PVC foils are weather resistant and, because of this, can be a veritable alternative to timber windows in order to combine heritage conservation and new windows and create an aesthetic emphasis.  


Because of this, heritage PVC windows can be permissible

Ultimately, heritage conservation authorities make the decisions regarding heritage conservation and new windows and/or specify which renovation measures are possible, feasible and necessary and whether PVC windows are at all allowed in an old building. In other words, house owners have to reach agreement with the authorities beforehand. An assessor will inspect the building to see whether the installed material is historically valuable and whether it can or must be preserved. If this is the case, drawings will be used to check what the old windows looked like previously. Based on this, there will be specific requirements and conditions that the house owner has to fulfil. In this scenario, heritage conservation will not allow new windows and it will be extremely difficult to obtain an approval that will enable the house owner to install PVC windows in the old building.  
Would you like more information about heritage conservation and new windows, renovation or renewal? Contact one of our local partner companies.