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Under the guidance of architect Stephan Tanner of INTEP, LLC, a Minneapolis- and Munich-based consulting company for high performance and sustainable construction, Waldsee BioHaus is modeled on Germany’s Passivhaus standard: a highly-efficient building design (beyond that of the U.S. LEED standard which improves quality of life inside the building while using 85% less energy than comparable U.S. structures.

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BioHaus Energy Comparison Graph

Listen to Waldsee BioHaus architect, Stephan Tanner, talk about the Passivhaus standard.


World’s largest environmental foundation helps fund Waldsee BioHaus: Deutsche Bundesstiftung Umwelt (DBU)
Thanks to the first-ever grant to a North American institution by the DBU (which has made more than 6,000 grants in Europe since 1991) a new “green generation” will soon be connecting Germany and the U.S.

Since Germany is a leader in environmental practices, Dan Hamilton, Dean of Waldsee, and Christine Schulze, Executive Director and CEO of Concordia Language Villages, proposed a partnership with the Deutsche Bundesstiftung Umwelt (DBU) to build Waldsee BioHaus. The DBU approved a grant of more than $650,000 to build Waldsee BioHaus Environmental Living Center based on the German Passivhaus standard and to be a showcase of German technology and innovation in North America.

Through innovative educational curriculum, specifically around the topic of sustainable living in Germany, Waldsee BioHaus will spark the exciting transfer and exchange of environmental education across the Atlantic between the U.S. and the German-speaking world.
For example, Concordia Language Villages is already involved in a new partnership with the U.S. National Park Service and the German branch of EuroParc because of Waldsee BioHaus. Collaboration will be focused on enhancing educational programs and the outreach of the parks based on the U.S. Junior Park Ranger model.

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Passivhaus Certificate

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Passivhaus Certificate

German Version

There are currently more than 6,000 certified Passivhaus buildings in Germany. But only one in North America.

Waldsee BioHaus Environmental Living Center is modeled on the Germany’s emerging Passivhaus standard: a highly-efficient building design which improves quality of life inside the building while using 85% less energy than comparable U.S. structures.

A Passivhaus building is one that maintains comfortable temperatures with low energy requirements during winter and summer periods. The Passivhaus standard was developed by the Passivhaus Institute. For additional details visit http://www.passiv.de.

The numbers behind the Passivhaus
In contrast to the U.S. Green Building Council’s LEED (Leadership in Energy and Environmental Design) energy criteria through which a consultant can self-declare certification based on an interpretation of a defined state building code, the German Passivhaus standard is a quantifiable system which must be proven by use of defined calculation tools and verification by the Passivhaus Institute itself to achieve certified status. These calculations have to be submitted in the engineering phase, before construction begins, to verify that it’s even feasible for certification to be achieved. A “blower-door test” (explained below) then confirms certification, proving that the final construction is of high enough quality to support the original design and engineering specs. No easy feat – especially in cold northern Minnesota winters! But Waldsee BioHaus did it. Here’s the story by the numbers.

Ta-daaa! The Final Results are in!
Here are the final results of the Passivhaus calculations for Waldsee BioHaus:
  • Specific heating energy requirement of 13.7 kWh/m_a = < 4,350 Btu/ft2°yr
  • Specific primary energy requirement of 44.9 kWh/m_a (14,250 Btu/ft2°yr)
  • Air tightness test result n50 (Blower Door Test) is 0.18 h-1
The Passivhaus standard building-performance goals of Waldsee BioHaus was achieved through the use of primarily local building contractors and at least 85% of commonly available U.S. building components. A few German building components were imported to meet some of the very specific requirements of the Passivhaus standard and partially because sponsors made them available. These components primarily included vacuum-insulated panels, windows and a ground-to-air heat exchanger. Other than that, Waldsee BioHaus is an example of a highly energy-efficient building that can be constructed with domestic components.

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BioHaus Results

Waldsee BioHaus declared the “tightest building” in the U.S.
Air tightness of the BioHaus building envelope demanded special attention. Uncontrolled air leaks were minimized and a Blower Door Test determined Waldsee BioHaus to have an air tightness value two and a half times better than the Passivhaus requirement – approximately 20 times better than current construction standards!

In addition, the unique air exchange/heat recovery unit of Waldsee BioHaus helps the building breathe in order to maintain healthy and comfortable air quality.

Waldsee BioHaus passed the Blower Door Test with flying colors! Gary Nelson, one of the pioneers of blower door testing in the late 1960’s came to Waldsee to personally conduct the test. The technology used in this test determines the air tightness of a building, a major factor in energy conservation. The Passivhaus Institute requires, among many other things, that buildings must pass this test under stringent criteria. It was the last major hurdle to clear for Waldsee BioHaus to become eligible for official Passivhaus certification. Gary Nelson has performed hundreds of these tests and he declared the BioHaus the tightest building in the United States!

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Blower-Door Results

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The real beauty of Waldsee BioHaus might not be found in any one detail itself. It might really be in taking a step back and admiring the dimensionality of the entire building itself. From the fun German language and cultural learning environment for kids to the sophisticated sustainable building construction to the overall philosophy behind the design.

Working with so many talented people to make Waldsee BioHaus a reality, architect Stephan Tanner was the man with the plan.

Learn how the architect conceived and created Waldsee BioHaus.

Waldsee BioHaus design combines two key functional elements:
1. Private areas containing dormitories and apartment – the base and rear of the building as represented by the blue stucco and its massive feeling walls.
2. Public areas for gathering, playing and learning – the light, reflective part of the building as represented by the aluminum siding and thinner walls.

The BioHaus design concept is inspired by the vision of immersion learning and explores three different types of inside/outside relationships, establishing a relationship between nature and Waldsee BioHaus through the German themes of Durchblick, Ausblick and Einblick.

Immersing into a different culture starts with the recognition that a different culture is based on a different perspective and therefore has a different understanding of the world. The architecture of Waldsee BioHaus helps students experience this first hand.

The openings, windows and doors of Waldsee BioHaus reflect three basic principles of gaining understanding through ‘perspective’ through the German words of Durchblick, Ausblick and Einblick.

Durchblick means perspective, vista or view in German, but it also means “seeing through” something. Forest is the main natural element in northern Minnesota through which one walks to enter Waldsee BioHaus. Entering it is accompanied by also “seeing though” the building into the forest.

Ausblick also means perspective or vista in German, but it also means “seeing into” the future. The large windows to the south give this sense of perspective to the students using the common room or the studio – the place of learning and experiencing.

Einblick means to “see into” or inspect in German, but it also means “gaining insight.” The small window to the west in the studio symbolize this – the places where students would be learning about the environment.

All are stimulating themes to explore while living in Waldsee BioHaus – to foster the learning and experiencing of modern German living, sustainable building design and technology in the German language.

Listen to Waldsee BioHaus architect, Stephan Tanner, talk about the art behind the building.

Waldsee BioHaus is cutting-edge sustainability design in the U.S. The functionality of the building and it’s design are in keeping with Concordia Language Village’s philosophy of ‘”language learning through cultural immersion.”

The building’s design will facilitate environmental living and learning through its design features and sustainable construction detailing. As an environmental living center, Waldsee BioHaus showcases cutting edge approaches to energy conservation and innovations in sustainable building design including:
  • Energy-standard-based-design using the German Passivhaus standard
  • Extensive green roof
  • Low impact and healthy building materials
  • Simple building design and technology
  • Use of alternative and renewable energy resources
  • Low energy use mechanical equipment and appliances
Key sustainability features
Compact footprint and volume. A two-story design with a nearly square footprint, resulting in a compact building form with a low surface area to volume ratio.

Optimal Zoning. The location of areas used mainly during the day were given priority in regard to access to daylighting. Dormitories were located on the lower level and oriented toward the east and the apartment on the upper level is oriented to the north (bedrooms) and east (living/dining room). Service areas like, toilet rooms, showers and mechanical room on the lower floor are compact and centrally located for minimal and efficient mechanical installation needs.

High performance building envelope. The building envelope is highly insulated. Specific attention was paid to insulating throughout the slab floor to the ground, exterior walls to the roof including windows and doors. A new insulation technology, Vacuum Insulation Panels (VIPs), were used on the upper floor for the exterior walls with aluminum cladding and were juxtaposed to the traditional insulated stucco walls, allowing these insulation approaches to be showcased for educational purpose. A flat roof form was selected for this design with an extensive green roof. In the summer the green roof design and the vegetation on the roof serves to retain rainwater and reduce the risk of erosion (serving to meet County requirements for erosion control plans) and establishing a heat buffer. In the winter time the flat roof form allows snow to remain as an additional insulation blant on the roof.
Effective daylighting and passive solar gain. This current design for the Waldsee BioHaus is optimal for an effective use of daylight and solar gain in the winter. Common Room and Studio are oriented toward the south with additional transom lights along the north wall.

Appropriate building technology. The need for a ventilation system and high air quality required 100% fresh air insuring that indoor air not be re-circulated, a ground to air heat exchange system for the fresh air intake and a high efficiency heat recovery system. Heating requirements are met using ground source heat pump and passive solar gain. The high volume hot water needs are met with a solar hot water system. The residual energy requirement is met using electricity as the energy source. A photovoltaic system is planned with an annual energy generating capacity above the electrical need of Waldsee BioHaus and will be implemented when financing is available.

Low-emission building products. The design of Waldsee BioHaus strives to achieve well-being and a healthy environment within the building. This requires low-emission building products and materials to be used. This strategy serves to meet regulatory requirements and to create a healthy living and working environment for the building’s occupants – an especially important strategy in designing spaces to be used by children who increasingly deal with allergies and chronic illness at young ages and who are sensitive to increased amounts of environmental toxics and contaminants.

Listen to Waldsee BioHaus architect, Stephan Tanner, talk about the science behind the building.

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