Protecting both the climate and historic buildings
Deutsche Wohnen’s districts are witnesses of the past set in stone and many also represent milestones in architectural history. This applies in particular – but in our opinion, not exclusively – to the residential estates which feature in the list of World Heritage sites. All buildings deserve protection, including those which are not listed historic buildings, such as the Eisenbahner estate on Gallwitzallee in Berlin-Lankwitz.
Reconciling the preservation of architectural memory with increasing the tenants’ well-being and protecting the climate is not always straightforward. But it is feasible, as demonstrated by the maintenance and refurbishment project on Gallwitzallee, where modern bathrooms, new facades and more appealing outdoor areas are in the tenants’ interests. Changing over from a decentralised to a central heating supply with condensing gas boilers and achieving targeted thermal insulation with mineral wool lead to a reduction in primary and final energy and an approximately 650-tonne reduction in the related climate emissions per annum. The preservation of historic buildings we have prescribed ourselves is demonstrated in particular in the details – the entrance doors are being restored in keeping with their original character and the wooden casement double windows looking out onto Gallwitzallee are being carefully treated and reinstalled in line with the look of the facade at the time it was built. Away from the street-facing facade, we are replacing the double windows with modern insulated windows with a wooden frame. Approximately 70% of the total investment sum is being used for maintenance and is therefore borne solely by us. The remaining 30% are the basis for the legally permissible cost allocation, naturally taking into account any of the tenants’ personal financial hardship cases.
As far as climate protection is concerned, we think far beyond just the district on Gallwitzallee, because the building sector in Germany is responsible for approximately a third of all climate emissions and therefore has a key part to play in climate policy goals being achieved. To date, there have been few holistic approaches that consider the restructuring of existing districts. We therefore presented an overarching concept for the sustainable carbon-oriented refurbishment of existing districts together with our partners innogy and Transsolar as part of the joint project of Foundation 2° and the WWF entitled The Road to a <2° Economy. At the heart of the concept is a blueprint with a mix of refurbishment measures such as facade insulation, window replacement, adding new storeys to a building, the installation of photovoltaic systems on the roof, the use of combined heat and power systems, the use of rainwater and new mobility concepts. Our partner Transsolar put this concept to the test in practical terms with our current building project on Gallwitzallee. It found that carbon neutrality for the district was only possible with a great deal of technical and financial input.
The study confirmed to us that we have adopted the correct approach and are on the right track. Our extensive measures have enabled us to achieve an approximately 50% reduction in primary and final energy and therefore also in the related climate emissions. At the same time, the necessary infrastructure was put in place for us to be able to respond flexibly to future technological developments and further optimise the heating supply system, for example by means of storage solutions.