The Webermühle development in Neuenhof houses 368 rental apartments. The settlement on a peninsula in a loop of the Limmat was built on the industrial site of a former weaving mill and was ready to move into in 1984 after ten years of construction. Planned by the architectural office Steiger Partner AG and built by Ernst Göhner AG, the Webermühle with its different volumes offers living space for up to 1,500 residents. Despite the very high density, the apartments with the four rows of high-rise buildings arranged in a cross shape are characterized by a surprising foresight. Since 2008, the buildings realized in the “Göhner 3” modular construction system have been owned by a real estate fund from Credit Suisse Asset Management.
Ecologically and economically sustainable renovation
A good 40 years after moving in, the apartments no longer met today’s standards – neither in terms of appearance nor in terms of comfort. With an analysis of the building structure, the client started planning an extensive partial renovation in 2009, which was implemented in stages between 2012 and 2014. The portfolio strategy of Credit Suisse Asset Management attaches great importance to ecologically and economically sustainable solutions. With the modernization of the Webermühle, one wanted to make the living and green space more attractive for the tenants and to maintain the value of the property. On the other hand, the building technology should be brought up to date and thus the energy consumption should be significantly reduced. Better connections to public transport were also an important goal: Since the construction of a new inclined lift in 2015, Wettingen train station can be reached within a few minutes on foot.
Heat supply: switch to flow heat
The core of the energetic renovation is the reorientation of the heat supply. To this end, the client defined a clear goal right from the start: in future, the heat supply in the Webermühle should be at least 70 % CO 2 -free. Due to the size of the facility, Credit Suisse Asset Management wanted to have the heating system replaced by a contractor instead of producing heat itself. The sustainability of the solution proposed by ewz with a river water heat pump convinced the client even after a detailed examination by specialists.
White paper on the topic of energy-efficient refurbishment
In addition to the practical example “Webermühle”, the white paper “Energy-related renovations as an opportunity for the real estate industry”, which was created in close cooperation between ewz and the research and consulting company intep, offers insights into the relevance of energy-related renovations.
Knowing that the building sector is responsible for about a quarter of emissions, there is an urgent need to renovate the building stock. Because the few climate-friendly and energy-efficient new buildings will not have a major effect on the entire sector. At the moment we are in a renovation backlog. The current renovation rate of one percent must be doubled in order to achieve the climate targets.
Practical experience shows that during renewal processes, too little attention is paid to energy-related refurbishment compared to replacement new buildings. The landowners often lack basic information that shows them the economic, ecological and social potential of energy-related renovations. The whitepaper is intended to make a contribution to precisely this. There is a basic overview of the urgency, legal framework, benefits, opportunities and possible strategies of energy-related renovations.
The results of an ecological balance sheet (life cycle analysis, LCA) and an analysis of the life cycle costs (LCC), for example, form an excellent basis for decision-making. These quantitative assessment methods take into account the entire building life cycle.
