Serial Retrofits: Energiesprong pilot project started in Bochum

CO2-neutral living is possible thanks to net zero building retrofits using prefabricated elements

The core work on the retrofit project using the Energiesprong approach began today in Bochum (NRW) with the assembly of the prefabricated façade elements. This innovative approach raises buildings up to a climate-neutral energy level by  prefabricating the retrofit elements and digitizing the construction process. The multi-unit buildings in Bochum’s Harpen district have 32 apartments and these will remain inhabited during the retrofit work. The building owner is VBW Bauen und Wohnen GmbH from Bochum. The work is being undertaken by the construction company B&O Bau NRW GmbH, and the energy partner is Stadtwerke Bochum GmbH. The pilot project is supported by the German Energy Agency (Dena).

The Energiesprong approach promotes climate-neutral, net zero standard, serial retrofits using prefabricated elements. The buildings generate as much renewable energy per year as the residents need for their heating, hot water and electricity consumption, within a pre-defined framework. In the Bochum project, this standard is being achieved by installing insulation using prefabricated façade elements constructed using wooden panelling, and putting in place a renewable energy supply by installing photovoltaic modules covering the whole roof surface. The retrofit work is expected to be completed by the beginning of 2022.

What the project participants say:

Dena: Andreas Kuhlmann, President of Dena: “In order to reduce CO2 so as to achieve savings targets in the construction sector, we need innovation. This includes serial retrofits, which raise buildings up to a climate-neutral standard faster and more effectively. Energiesprong is a retrofitting solution with enormous potential for the climate and the economy, which we need to be market-ready as quickly as possible. Both VBW Bauen und Wohnen as the owner of this property, and B&O as the construction company carrying out the work, are setting an example for what still needs to happen to millions of buildings in Germany: fast, high-quality retrofits that are good for both tenants and the climate equally”.

Sebastian Eck, Innovation Team Manager, VBW Bauen und Wohnen GmbH: “With the Energiesprong approach, we have the opportunity to balance innovative solutions, sustainability and affordable housing. When it comes to serial retrofits, our focus is on four goals: firstly, we aim to shorten the retrofit time through serially pre-fabricating the components. Secondly, we develop CO2-neutral buildings with low energy costs. Thirdly, we undertake a sustainable approach by using renewable and high-quality materials, such as wood. And fourthly, we ensure security for our customers in the future through long-term performance because all the partners involved in the project will continue to monitor the buildings in the future in order to ensure that energy standards are complied with”.

Nadin Bozorgzadeh, Authorized Representative for B&O Bau NRW: “In new buildings, high-tech computer systems companies are our standard and we benefit enormously from the high quality and speed of serial prefabrication. The exciting challenge is to apply this to retrofits by moving full steam ahead to develop a standard, scalable product that can still react to the existing situation”.

The Energiesprong pilot in Mörikestraße, Bochum

The multi-unit houses built in 1967 in Mörikestraße are being given a new shell in the form of a façade constructed using wood panelling with large-sized prefabricated elements. Photovoltaic panels almost entirely cover the completely new roof. The panels meet the net zero performance standard and are what make CO2-neutral living possible. The façades and roof meet the KFW Efficient House Standard No 55. Each apartment will be equipped with a multifunctional unit for supplying the heating and hot water and controlling the ventilation in the living room. In the bathroom, kitchen and hallway, the used air is extracted and directed to the outside via air ducts. Similarly, fresh air is supplied to the unit, the air is then heated to room temperature by a heat pump, and then distributed evenly between the living room and bedrooms. High-quality window frames are also installed. The staircase will be refurbished and equipped with LED lighting. The apartments will also have new balconies and the ceilings in the basements are also being insulated with rock wool.

The Energiesprong approach in Germany

Dena coordinates the market development for Energiesprong in Germany and is supported by the GdW Bundesverband deutscher Wohnungs- und Immobilienunternehmen. The Dena project is funded by the Federal Ministry for Economic Affairs and Energy (BMWi). The Energiesprong team guides and supports the development of serial retrofitting solutions and, together with industry leaders, sets new standards for comfortable, energy-efficient retrofits. Implementation of the initial pilot projects in Germany is also supported by the MustBe0 project, which is part-funded by the EU’s Interreg NWE programme. This includes the project in Bochum. Dena estimates that the potential for small to medium-sized apartment buildings built from the 1950s – 1970s at around 300,000 buildings in Germany alone.

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