by Daniel Spitzberg

Meinhard Hansen of the Architekturbüro in Germany gave a dynamic presentation on the UW campus Wednesday night about sustainable neighborhoods and “passive house” buildings that are anything but passive when it comes to energy cost savings.

In Vauban, a neighborhood in Madison’s sister city Freiburg, “the streets are free for living,” said Hansen. Cars are allowed in Vauban, but parking is not, which not only means biking and walking and public transport are the norm, but children playing and table tennis matches occupy the main streets. And while it might have required a Porsche to attain social status, Hansen says that everyone considers it “cool” to install solar panels, and nearly every residence, building, and even the university football stadium can brag about their lower electricity consumption and feeding excess power to the grid.

A very common fixture in Vauban is the “passive house” (passiv-haus in German), Hansen’s architectural specialty. The passive house concept, originally a Swedish innovation, is radically simple: thick, inexpensive insulation enveloping the building.

By boasting the comfort of a house that feels like summer throughout the winter, the passiv-haus building style has become very popular. Because indoor lights, computers, toasters, and showers all radiate heat, and because the average human being gives off 100 Watts, Hansen says a small party of “10 people can heat my house by themselves,” literally. Hansen says that although marketing efforts have relied on comfort, efficiency is still attractive. For example, while his mother-in-law has a house in the countryside that uses some 6,000 liters (about 1600 gallons) of heating oil per year, his house only uses 150 liters (or 40 gallons).

To achieve a 90 percent energy cost savings, the necessary building practices are straightforward: seal insulation properly, use triple-pane/triple-seal windows, and install a ventilation system that warms incoming air from outside with inside air. A slightly more sophisticated practice involves minimizing “thermal bridges”, that is, reducing building parts such as support columns that leak heat through insulation. Passive house design requires a 10 to 20 percent investment above average house construction costs.

More info:
www.solar-info-center.de
www.meinhard-hansen.de
www.madisonfreiburg.org