Serial refurbishment can accelerate the pace of transformation
Almost two thirds of Germany’s building stock was constructed before the introduction of the first Thermal Insulation Ordinance in 1979 and consume up to five times more energy than modern buildings. That adds up: about 21 million buildings in Germany account for around 35 per cent of the country’s energy consumption. This not only places a strain on the environment but also torpedoes Germany’s goal of achieving greenhouse gas neutrality by 2045. Moreover, in accordance with the EU Buildings Directive, all buildings in Europe are expected to meet net-zero standards by 2050.
And the reality? Germany is struggling with a substantial building refurbishment backlog. Despite the fact that an annual refurbishment rate of two per cent is required to achieve the country’s climate targets by 2030, the rate stagnated at just 0.7 per cent in 2024. If this trend persists, it is projected that only 275,000 residential units will undergo refurbishment by 2025, falling significantly short of the legally mandated targets.
A solution with potential: serial refurbishment
Serial refurbishment has the potential to deliver a breakthrough. This process uses prefabricated modules that act as a second skin on existing facades and, in the best case, allow buildings to be upgraded with high-performance insulation, integrated photovoltaics (BIPV), and controlled ventilation systems. Photovoltaic modules can be embedded in the new facade and supply a large proportion of the energy required for the building. Furthermore, the improved insulation reduces heating requirements, while the ventilation system ensures a constant supply of fresh air while minimising heat loss. Serial refurbishment is particularly well-suited for standardised buildings with uniform structures and facades, such as the large housing estates built between the 1950s and 1980s. The owners of these estates – large municipal, state-owned or private housing companies – are under increasing pressure to modernise their properties in line with ESG standards. The EU taxonomy requires companies to fulfil environmental sustainability criteria in order to be considered sustainable investments. ESG-compliant properties not only increase their market value but also reduce operating costs in the long run through energy savings. For capital market-oriented housing companies, ESG-compliant refurbishments are essential to remaining competitive and attracting sustainability-focused investors.
What is serial refurbishment – and what can it achieve in a best-case scenario?
Ideally, serial refurbishment could revolutionise the entire process of energy-efficient building refurbishment and transform even inefficient properties into climate-neutral buildings. For instance, consider a typical residential building from the 1970s with 20 units and a primary energy requirement of 300 kWh/m²a. Through serial refurbishment, this energy requirement can be reduced to less than 50 kWh/m²a. This cuts CO₂ emissions by over 80 per cent, allowing the building to meet its remaining energy requirements with the integrated PV system. This transformation is achieved thanks to the refurbishment method described above that effectively turns old buildings into fully-insulated, energy-generating structures. By enveloping the building in a protective “cocoon”, this solution could to a certain extent preserve the original structure and transform it at the same time. Remarkably, this process can be completed in a relatively short amount of time and with minimal disruption to residents.
What’s the hold-up in Germany?
In Germany, serial refurbishment is yet to really take off and faces various hurdles. On the one hand, there are very few providers with completed refurbishment projects to serve as references. On the other, most property owners are still busy laying the groundwork for future refurbishment projects. The most important aspect here – as banal as it may sound – is for property owners to define their objectives and carefully assess their portfolios to identify which buildings are best suited for serial refurbishment. Internal procedures and planning processes must also be reviewed, as serial refurbishments often differ significantly from traditional refurbishment projects. Special funding programmes, like the federal serial refurbishment bonus, aim to support property owners during this start-up phase. Initial pilot projects are already confirming that serial refurbishment could become an increasingly valuable tool as demand increases and experience grows.
The outlook: the dawn of a sustainable refurbishment culture
The German Energy Agency (dena)[1] and other key stakeholders are actively working on measures to speed up and streamline funding processes, eliminate legal obstacles, and enhance market acceptance in order to accelerate the expansion of serial refurbishment across Germany. There is no doubt that serial refurbishment can help to finally clear the refurbishment backlog and significantly increase the building refurbishment rate. Serial refurbishment also offers housing companies the opportunity to create attractive, ESG-compliant property portfolios for many years to come – without having to resort to drastic measures such as selling inefficient buildings. So, serial refurbishment is not a matter of “if” but “when”; it offers a sustainable answer to Germany’s energy issues within the building sector. It is efficient, it is expedient, and it is sustainable. The question we must now ask ourselves is whether we are content to carry on as usual – stuck in a traffic jam – or whether we are finally ready to change lanes?
[1] https://www.dena.de/projekte/energiesprong-deutschland-serielles-sanieren/
