CORPUS Magazine

New energy for a residential complex

The Brunckviertel, a residential complex in Ludwigshafen, Germany, underwent a complete energy upgrade about 10 years ago. But what is life like in highly insulated buildings? And has the insulation system delivered the promised savings? A comprehensive evaluation provides the answers.


Thermal insulation is neither energy-efficient nor cost-effective – that, at least, is what the critics claim. An energy upgrade, they say, only pays for itself after several decades and also sends rents spiraling. However, the Brunckviertel, a residential complex in Ludwigshafen, Germany, proves, on the contrary, that investment in progressive insulation can genuinely revolutionize energy consumption in a whole complex in the long term and noticeably improve the indoor climate at the same time.

In 1997, BASF embarked on this large-scale project with the goal of modernizing the residential complex dating back to the 1930s by consistently implementing resource-conserving and environment-friendly materials and technologies. Some ten years after completion of the final work, a comprehensive evaluation has been commissioned. Its focus is not only on aspects of efficiency, but also on tenants' well-being within their energy-upgraded four walls.
CORPUS talked to Ralf Werry, Head of Housing and Modernization at BASF Wohnen + Bauen, about the findings.

Ralf Werry
Head of Housing and Modernization at BASF Wohnen + Bauen

CORPUS: Mr. Werry, the Brunckviertel with its roughly 850 dwelling units is not exactly small. Refurbishing existing buildings on this scale is an ambitious endeavor – what was it that prompted the project?

RALF WERRY: The Brunckviertel, to put it mildly, had fallen behind the times. The room layouts were simply no longer in line with contemporary needs, and a growing number of apartments were empty and almost impossible to rent out. The complex was on the verge of sliding into decline, so we had to take action.

CORPUS: In the course of the project, there must have been a number of challenges to master – what was the biggest one in terms of the energy upgrade?

RALF WERRY: Initially, the energy supply was the biggest challenge. It was important for us to approach the project with innovative ideas. Since the BASF plant in Ludwigshafen is only short distance away, the obvious option at first was to use district heat from the plant. However, the anticipated quantities required were so minimal that it wouldn't have been worth it. Instead, several decentralized supply solutions were implemented – ranging from fuel cells, combined heating and power generation to condensing boiler technology. Geothermal energy and local heating give an indication of the innovative approach taken during planning. Together with municipal and regional government, we decided to aim for the passive-house standard. At the time, passive houses were all built from scratch – so ours was the first time existing buildings would be modernized to passive-house standard in Europe and possibly even worldwide. In all the buildings, we not only reorganized the room layouts and enlarged the bathrooms, but also replaced the windows and building services. Many of the components we needed for the project were not yet established on the market at the time.

1: The Brunckviertel in Ludwigshafen encompasses roughly 850 dwelling units. Refurbishing existing buildings on this scale was an ambitious endeavor.
2: Even more so as it was the first time existing buildings were modernized to passive-house standard in Europe.

CORPUS: Which products from the BASF construction materials portfolio did you employ and what's your evaluation of performance from the vantage point of the present, some ten years after completion of the modernization project? Has the insulation system lived up to your expectations?

RALF WERRY: A lot of innovative materials were employed during modernization. New at the time was latent heat storage plaster – a phase change material – that was used particularly in the passive-house, the so-called 3-liter-house, project. We also used NEOPOR insulating material that had only just arrived on the market. In the course of evaluation, we commissioned an external expert opinion, opened up facades and inspected the details. After more than ten years, there's no visible degradation at all. The few flaws that have emerged were entirely due to faulty application. Back then, the construction firms were still very inexperienced in applying such high-grade insulating materials to facades – simply because the product was so new and innovative. This is one reason why we attach so much importance today to having workers trained so that the construction materials are flawlessly installed. As far as the hard data are concerned, we've been measuring energy consumption in the various buildings over the years and found that consumption is in all cases below the previously calculated values. In the years to date, we've managed to save 387,000 liters of heating oil, which is equivalent to 13 tanker truck loads. Overall, energy consumption has been slashed by 80 percent, which means considerable reductions in heating costs for tenants. So our expectations have been more than fulfilled.

Saving effectst
387.000 liters heating oil in 10 years = 13 fuel tankers.
Carbon Footprint
- 830 tonnes of CO2 p. a. = 60 soccer fields of forest.

CORPUS: So the hard data already confirm the project's success. But what about tenant satisfaction, which is also highly important? How have tenants reacted to the energy upgrade of the complex?

RALF WERRY: The response has been thoroughly positive. We had the Brunckviertel tenants surveyed by the Hildesheim/Holzminden/Göttingen University of Applied Sciences and Arts (HAWK) to find out what it's like to live in highly insulated buildings. Over 85 percent of tenants feel comfortable or even very comfortable in their modernized homes. At the beginning there were a few teething problems – but that was our fault because we hadn't sufficiently explained the project to tenants. Having given them a kind of "user's manual", satisfaction is now high. The most important criterion for the feel-good factor is comfort followed by brightness. Both needs have been met by the modernization of the Brunckviertel. So the results have been positive across the board.

In our climate, it's always a good thing to keep the heat in the building. So we practically never have to heat the building except on a few, very cold days in winter. Consequently, we pay almost nothing for heating.

Peter Doland, Brunckviertel tenant
A lot of innovative materials were employed during the renovation as many of the components needed were not yet established on the market at the time.

CORPUS: Let's take a brief look ahead. How will our buildings have to perform in terms of energy efficiency in the immediate or more distant future?

RALF WERRY: Buildings will soon have to supply themselves. They may even have to generate extra energy so that electric automobiles, for instance, can be powered. New high-performance construction materials will also be necessary and important for construction in confined spaces. This applies not only to the insulation sector, but also to concrete. Particularly important is the concentration on sustainable building, where it's a question of studying the life-cycle of construction materials and selecting them accordingly.

CORPUS: Thank you, Mr. Werry, for these exciting insights into the project.

1: The evaluation showed that absolutely no flaws in the facade could be seen after more than ten years.
2: In the Brunckviertel, 3 liter house standard was achieved for the first time in existing buildings – at the time, 3 liter houses were all built from scratch.
3: A survey of tenants showed that the majority of the residents felt very comfortable in their modernized homes.
4: The insulation system has surpassed expectations– energy consumption has been slashed by 80 percent.



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