Germany’s Houses of the Future
Because of increasing energy prices, heating costs, rent, and utilities are going through the roof. Evonik Industries is using a different approach, with a comprehensive energy improvement program for residential units. In a pioneering pilot project, we’re currently refurbishing an apartment block in Düsseldorf to convert it into one of the most energy efficient buildings in Germany: the “Three-Liter House.”
The high energy consumption of many of the older buildings in the portfolio, dating from the
1950s, 1960s, and early 1970s, is a major concern. Normally, these buildings consume about three
times as much energy as new buildings, about 87 percent of which is required for heating and hot
water alone.
Evonik is now demonstrating what it means by improving 24 housing units on Wäschlacker Weg in
Düsseldorf. The apartment blocks, built between 1964 and 1969, form part of the Niedrigenergie-Haus
im Bestand (Efficient Homes) project initiated by the German Energy Agency (dena) in collaboration
with the German Federal Ministry of Transportation, Construction, and Urban Development and
launched on a country-wide Campaign Day in June 2007.
The Three-Liter House: an ambitious goal
Evonik has set itself the target of reducing the primary energy requirement of the buildings by
87 percent, from 286 kilowatt hours (kwh) per square meter per year to just 36.2 kwh, by
efficient and comprehensive retrofitting.
The improved multifamily apartment blocks will then more than satisfy the requirements of the
German Energy Conservation Ordinance, according to which a comparable new building may have a
primary energy requirement of 91 kilowatt hours per square meter per year.
Your own mini-cogeneration plant on the block
The special feature of the Düsseldorf project is that, in addition to designing an advanced heat
insulation system and passive windows with electric blinds, Evonik is developing a completely new
building technology.
A mini-block cogeneration plant supplies the building centrally with hot water; the
ventilation systems allow for the efficient recovery of waste heat. Using a special switch known as
an “optimizer,” the tenant can ensure that, for example, the heating is activated at different
times over the weekend than during the week.
Improvement pays off for tenants
For the tenants of the Three-Liter House, these measures will pay off in hard cash. The rents for the newly retrofitted units will remain stable for the most part. Evonik is therefore using the improvement as an opportunity for a complete visual overhaul of both the apartment blocks. The facades have been completely redesigned, and each apartment now has a new balcony or patio.
Contribution to climate protection
Energy improvement also makes an important contribution to climate protection. The Three-Liter House in Düsseldorf reduces carbon dioxide (CO2) emissions by 160 metric tons per year. According to dena’s calculations, Germany could be reducing CO2 emissions by 37 million metric tons in the year 2020, if existing residential buildings are now retrofitted using state-of-the-art energy conservation technology.
