Journal: September 3, 2007

Sausage, beer and the land of the Passivhaus: Bavaria, Germany

Bavaria has proven itself to be the perfect start to my fellowship.  Thanks to the thorough and generous planning of my host, Heiko Seen, I have spent the past week and a half becoming well acquainted with the Passivhaus concept and timber construction in Germany. I also had the pleasure of staying out in the Bavarian countryside with Heiko, his wife Christina and daughters Ann Kathrin and Patricia.  They welcomed me into their home with coffee, breakfast and a full tour of their low energy timber frame home.  Ann Kathrin, three years old, instantly began my lessons in Bavarian dialect while Patricia, a little over one, just liked to make faces at me, giggle and chew on pretzels. 

The first few days I spent exploring Bavaria and getting acquainted with German culture.  My first glimpse of this was at the train station with the sight of men in Lederhosen drinking beer at 10 am.  My hosts took me out on day two to Lake Kimsee at the base of the Alps, where the crazy King Ludwig built one of his many castles that almost bankrupted Bavaria.  The tour of the castle confirmed that the man truly had most of his screws loose, if they were not gone entirely. Munich turned out to be a long day of wandering around in the rain in gardens, markets and historic areas before setting up camp in the Hofbrauhaus for sausage and a beer.  I saw the immense set up for Oktoberfest (and was told several times that I should stay through to see it…maybe next year), went to the 1972 Olympic Village (I did not even think about the events recounted in the film Munich until afterwards), and strolled around the immense English Gardens.  The next day Christina and I went into the village of Landshut to have lunch and see the historic town set along the banks of the river Isar.  Landshut, interestingly enough, is also home to the world’s tallest brick tower.  In 1475 there was a wedding between a Bavarian duke and a Polish princess, which is reenacted in a festival every four years in full costume, and the castle in which they once lived still remains on the hill above the town.  As a result of the festival, the facades of the buildings in the Old and New Town must be preserved, no matter how the space behind changes hands over the years, and no modern permanent signage is allowed. 

While I will try not to get too technical and spare those of you who are not particularly interested in the business of architects and builders, I learned a lot during this short stay and the Passivhaus concept is really worth some attention, so bear with me.  This building concept was established by a physicist, Dr. Wolfgang Feist, who wanted to build a low energy home that enabled its inhabitants to live comfortably inside despite external conditions.  Dr. Feist used calculations and building simulations to arrive at guidelines to construct a building that would rely on passive energy from the sun, earth and humans to maintain a comfortable living environment.  In 1990 Dr. Feist built the first Passivhaus home based on his research.  To date, there are over 8,000 Passivhaus buildings in Germany alone, with expansion into other countries each year as the concept is adapted to various materials and climates.

In order to be officially recognized as a Passivhaus building—certified by Dr. Feist’s Passivhaus Institute in Darmstadt—the building must meet some basic guidelines for energy use:
-must consume less than 15 kilowatt hours per square meter in one year for heating energy
(limit 120 kWh/m²/year for all energy needs)
-the heating source must have a specific heat load less than 10 watts/ m² per hour
-must have an air exchange rate of 0.6 times the volume of the house in one hour (this is tested at a pressure of 50 pascals using a “blower door test” to check for air leaks)
This efficiently operated structure is designed to be extremely airtight, compact and efficient, with walls as thick as 40 cm (almost 16 inches)!  The Passivhaus Institute does not define building materials or heat sources, allowing the concept to be widely adapted by designers to different uses and clients.  Common features include southern solar orientation, triple glazed windows, and super insulation.  Air is brought in to naturally ventilate the interior, though this can be supplemented with a central or radiant heating system powered by the sun (energy from photovoltaic panels is subsidized in Germany so they are a common sight), a pellet oven, natural gas or other fuel.  Outside air is heated by running in an underground pipe before entering the building and is also passed through a heat recovery system.  Because of the air tight and heavily insulated structure, there is a very long and subtle phase shift in temperature changes caused by exterior conditions, making this a great system for both hot and cold climates.  The result, I can say from experience, is a comfortable, quiet interior space in which you do not even notice the flow of warm or cool air or the quality of air because it is always maintained through this subtle, well designed system. 

The Seen’s house was a culmination of Heiko’s experiences as an engineer, carpenter, and now an employee of Steico, a German manufacturer of timber construction materials with an ecological slant.  The house has 40 cm thick walls built with Steico structural wood fiber I-joists and wall panels filled with wood fiber insulation produced from scrap wood chips.  The Seens chose to supplement their natural ventilation system and solar hot water panels with a central pellet oven that heats the air in the main living spaces and helps heat water in the winter when there is not enough sun for the solar panels to suffice.  In the Passivhaus concept, a building is designed from a holistic perspective, so nothing is overlooked, from air seals around windows and gaps under interior doors, to vent size and location and prevention of thermal bridging within walls.  In this case, the whole system is monitored by a computer, allowing Heiko and his family to truly live comfortably and efficiently throughout the year.

Steico’s promotion of timber construction materials is particularly appropriate in Bavaria and its surrounding areas where timber resources are abundant and there is a tradition of timber building.  Many of the traditional farmhouses I saw used a timber frame above a stone base, designed to use the heat from the animals stored in the stone base for the comfort of the humans above in winter.  All of Steico’s wood is certified by the Forest Stewardship Council and regionally extracted to produce various types of fiber insulation, wall and floor panels, and structural systems through a wet or dry production process.  The resulting products are dense, highly fire resistant, with low thermal conductivity and high specific heat, mostly natural and vapor open, allowing the walls to restrict air flow without developing moisture problems that affect air quality.  Heiko’s house is a testament to the potential of this system, inspired by Passivhaus concepts, to create an extremely efficient and livable environment.  Steico has also begun to use hemp for insulation (though aside from California, I doubt this will take off in the States any time soon).  Another benefit of timber construction is the ease of prefabrication, which reduces waste and enables short on site construction time, further protecting materials from weathering. 

The rest of the week I spent meeting with architects, engineers, ecological material dealers, builders and Bavarian timbermen. Heiko took me to his office, where one of his engineers gave me the best physics lesson of my life.  Wolfgang was able to explain building physics so clearly that I am certain I learned more memorable lessons in those two hours than I did in an entire semester of physics at Vandy.  That afternoon we went to Baufritz, a high end timber frame housing company that specializes in green materials and renewable resources.  Following my orientation to the engineering, sales and construction behind the Passivhaus industry, I met with architects specializing in Passivhaus design and consultation and saw how the concept can be adapted in various designs.  We also stopped by a timber frame construction company where Heiko used to work that specializes in fabrication of panels, Pletschacher Holzbau. 

After a relaxing weekend in the country, enjoying the low energy lifestyle, I said goodbye to Bavaria, and went to stay with another Passivhaus architect/engineer/carpenter, Gerrit Horn.  Touring his family’s home and his office after a weekend of recharging and reflection gave me the chance to piece together all I had learned and ask any remaining questions I had about building and living in a Passivhaus home.  I also talked to his American neighbors who loved living in their Passivhaus apartment built by Gerrit so much that they are looking into building one of their own when they move back to the States.  To complete my lessons on the Passivhaus in Germany, on Tuesday I had the honor of actually meeting with the “Pope of the Passivhaus,” Dr. Feist himself.  I had a chance to speak with Dr. Feist and hear about his experience with developing the concept and then toured some of the projects overseen by the Passivhaus Institute in Darmstadt.  When I tried to convey my thanks to Heiko, he would just reply that he just wanted to set the bar high for my future travels.  And he has.

From Darmstadt, I made a short stop in Berlin before catching a flight to Stockholm, Sweden.  My host was a Vanderbilt alum and her family, including a son who is looking to go to the states for college, so we talked a lot about life at Vandy.  I was fortunate to have the chance to meet up with a former Vanderbilt professor and his wife, and get a personal tour of the city for the one day that I had there.  Professor Jim Lang, who taught my Development for a Small Planet course put me in contact with these friends.  We started at the Bauhaus Archive where there was an exhibition on 1920s housing tenements in Berlin that are being considered for adoption as UNESCO World Heritage Sites. After lunch we toured the city a bit, stopping at main sites like the Reichstag and Brandenburg Gate, but also at lesser known things like the Schadow House which survived bombing during the World Wars and the devastation of East Berlin during the Cold War.  The only disappointment for me was the Holocaust Memorial by Peter Eisenman.  We arrived to a sea of impersonal concrete blocks which were being used as a playground by people of all ages.  Tag, hide and go seek and competitions to see who can jump furthest are not your typical ways to remember millions who lost their lives in a terrible tragedy.  For a moment when I was standing among the tallest of the blocks, I had a flitting sensation of the isolation and threat that Eisenman may have intended with his design.  Until two kids scurried past playing tag and a teenager went sailing over my head trying to race his friend across the blocks.  Needless to say, there was not much in the way of reflection, sadness, or memories at this memorial.

Most of you probably will not believe that was just an overview of my experience with sausage, beer and passive solar buildings, though I swear it was.  Now Germany has me off and running.  After a long weekend visiting family friends in Stockholm, I am off to London before I make my way to South America starting in mid-September.  Ciao!

 

More information and a guide for developing a Passivhaus project are available on the Passivhaus Institute’s website http://www.passiv.de/.

Steico: http://www.steico.de/