Actively Passive: The New Wave of Energy Efficient Homes – International – SPIEGEL ONLINE – News

The New Wave of Energy Efficient Homes

By Bernward Janzing

With scarce resources and the environment back on the agenda, German architects are competing to design the most energy-efficient homes.

Passive homes have little need for conventional heating systems: they use no more than three liters of heating oil per square meter each year.
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Passive homes have little need for conventional heating systems: they use no more than three liters of heating oil per square meter each year.
At first glance, the row of homes in Mannheim’s Gartenstadt neighborhood looks anything but spectacular. The buildings along Freyastrasse in the German city are classic two-story, pre-war architecture: 24 apartments with a total of 1,300 square meters (14,000 square feet) of living space, built during the early 1930s. The complex has since been renovated — but the changes are technical rather than aesthetic. The building has become an energy-efficiency wonder — a three-liter house.

Heating the apartments requires no more than the equivalent of an annual three liters (0.8 gallons) of heating oil per square meter (10.8 square feet). It’s a striking degree of energy efficiency for a historical building. Even newly constructed homes are legally allowed to consume twice as much under German law.

The working class housing complex in Mannheim is a pilot project. The GBG construction company wanted to show just what can be achieved through the renovation of historical buildings. Scientists at the University of Stuttgart provided their expertise during the planning and construction of the apartments.