Energy-Efficient Buildings: Austrian Students Compete for Solar Decathlon 2013

bridges vol. 38, August 2013 / Feature Articles

By Isabella Zwerger


Austria is a leading country in the field of sustainable construction and solar energy technologies and has the highest density of passive houses worldwide. But not many people know that. So why not choose one of the most outstanding challenges in the world to show Austrian know-how in an international arena?

Logo for the LISI Austrian Solar Decathlon project.

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The "Solar Decathlon" hosted by the US Department of Energy (DoE) is a biennial competition for collegiate teams to design, build, and operate solar-powered houses. The aim of this award-winning program is to promote the application of solar technologies in buildings. Twenty teams have the opportunity to demonstrate their ideas of a cost-effective, energy-efficient, and attractive building powered by the sun. During some 10 days, the buildings will be open to the public and are judged by a jury in 10 different areas such as architecture, energy balance, comfort zone, etc. The winner of the competition is the team that best blends affordability, consumer appeal, and design excellence with optimal energy production and maximum efficiency.

In January 2012, the DoE had reviewed 130 applications and selected 20 university teams to compete in the Solar Decathlon 2013, to be held in Orange County Great Park in Irvine, California. Team Austria, led by the Vienna University of Technology, was invited to SD 2013 as one of only two European teams (the other being from the Czech Republic). Karin Stieldorf, project leader of Team Austria, has been researching and teaching the topics of the Solar Decathlon for many years: "It is very important for me to establish the connection between energy efficiency and design and to sensitize future architects to sustainability issues. We participate in the Solar Decathlon competition, as I am convinced that we are able to compete with the best."

LISI – The House

The LISI House.Sponsored mainly by the Federal Ministry of Transport, Innovation and Technology (bmvit) within the Research and Technology Program "Building of Tomorrow," Team Austria has developed the Austrian project "LISI" during recent months. The building concept is based on three pillars: sustainable design, renewable energy, and ecologically acceptable materials. In coordination with passive solar strategies, active system components like Photovoltaic (PV) will cover LISI's energy demands for heating, cooling, and electricity, and in the end lead to an energy-surplus home – a building that supplies more energy than it consumes. The excess energy can then be fed into the power-supply grid or stored to power electric vehicles.

Claus Schnetzer, who, together with Gregor Pils, manages the LISI project, points out that the project aims to develop a building primarily made from renewable materials. "Besides cellulose (wastepaper) as insulation material, we primarily use timber from Austria. Nine different kinds of timber and derived timber products are applied in the building, each ideally matched to its future function. The house is made of nearly 100 percent wood. But it was also a major goal to use these resources in a sustainable way: Nearly every part of a tree will be used, even the bark is used as a decorative plate in the interior space." The use of wood-based materials in housing can achieve a positive effect on the indoor climate and living comfort.

LISI | Solar Decathlon Team Austria - Walkthrough from LISI | Team Austria on Vimeo.


Changing Environment

The building sector is one of the biggest consumers of resources and energy, e.g., 50 percent of waste material and nearly 40 percent of final energy consumption can be assigned to the building sector. In consideration of climate change, rise of energy demand, shortage of resources, risk of secure power supply, as well as demographic and social change, sustainable building adaptation plays a key role in both national and European-level politics. The European Commission has identified the building sector as crucial for technology development, energy savings, and climate protection. The EU Energy Performance of Buildings Directive 2010/31/EU (EPBD) obliges EU Member States to set minimum energy performance standards for new and reconstructed buildings, e.g., it commits the public sector to erecting new public buildings as nearly zero-energy buildings by 2019. Integrative planning and deploying innovative building technology such as energy-efficient building envelopes, appliances, and lighting, make a major contribution to achieving this goal. Research and development are intended to provide a basis for entirely new, sustainable approaches for new buildings and for renovating existing ones, and so have the potential to transform today's built environment.

Within the Austrian Research and Technology Program "Building of Tomorrow", new technologies and concepts for innovative accommodation and energy-efficient buildings have been developed and demonstrated. Launched in 1999 by the Federal Ministry of Transport, Innovation and Technology (bmvit) the program counts as one of the most successful R&D programs in the field of sustainable building. In nine sequential calls for proposals, more than 400 research projects were funded with approximately €63 million. Besides basic research on socioeconomic issues, projects on applied research and development of technology and components – such as passive house windows, facade-integrated solar collectors for water and space heating, or new building materials made of renewable resources – were conducted within the program.

About 55 pioneering new building and renovation projects have been carried out to demonstrate new concepts and technologies and make the theory and technology more accessible and tangible for the general public. The LISI House is one of these. It has been developed to meet the above-mentioned challenges for a broad range of users and sites. The building, designed as an atrium house, also offers spatial flexibility and takes social aspects into account. "Since we have defined the plus-energy standard as a prerequisite for LISI, we try to pay more attention to the needs of the user. As little technology as possible will be used, and it will be integrated into the house unobtrusively. The essential element will be living," says Gregor Pils. Depending on climatic and social preferences, LISI can be transformed from an isolated cocoon to an open and communal gathering house by adjusting the outermost façade and shading elements. "Our Solar Decathlon project will demonstrate that it is not necessary to choose between energy efficiency and architecture, but both requirements can harmonize and work together."


Suitability for smart cities

More than 50 percent of the world's population today lives in cities, and this rate is still increasing. In Austria, work on strategies for the City of Tomorrow ("Smart City") has been in progress for years. Together with bmvit, in 2010 the Austrian Climate and Energy Fund started the funding program "Smart Energy Demo – Fit for SET," whose goal is to initiate major demonstration and pilot projects for smart cities and urban regions. Existing technologies and (sub)systems in the fields of energy, transport, building, and environment will become innovative and interactive total systems.

Plus Energy Network Reininghaus Süd.The City of Graz is exemplary in promoting different projects for sustainable urban development. The project "Smart Future Graz" will demonstrate urban technologies for using renewable energy sources (solar power, smart heat grids, integrated façade technologies, etc.) with the aim of creating a sustainable, livable, and smart city district around Graz' central station with the lowest possible emissions ("Zero Emission"). Another project deals with developing a master plan for the district Graz-Reininghaus and the implementation of future-oriented city building blocks, such as the building network "+ERS - Plus Energy Network Reininghaus Süd".

These different research activities demonstrate the essential role of elaborated smart city concepts in which energy-efficient and sustainable buildings play an important role. The LISI House offers flexibility and suitability for urban-development strategies. With different combinations of LISI house types, the residential density can be increased and thus provide optimized land use. With minor adaptations to the thermal envelope construction, LISI is also geographically flexible.

To be prepared for future urbanization challenges, Austria is intensifying its research activities in the field of smart cities. Based on the results of "Building of Tomorrow," the bmvit will invest €40 million for a new perennial R&D Program called "City of Tomorrow" that will focus on the development of urban technologies and technological systems for smart cities. The first call for proposals is planned to open in September 2013. Further information will be available at:


Austrian Architects in California

Team Austria has to demonstrate their LISI House during the competition in October in Irvine, California – a place where other Austrian architects have been very successful. Richard Neutra, who moved from Austria to Southern California in the 1920s, was cofounder with Rudolf Schindler of the "Architectural Group for Industry and Commerce." Neutra and Schindler are recognized as among of the most important early modernist architects creating new styles suited to the California climate. Due to its modern architecture, the Schindler House in West Hollywood is still one of the most noteworthy houses in LA (see article, "The best houses of all time in LA" in the Los Angeles Times, 2008).


The Market Potential of Prefabrication

Neutra was one of the first architects to design and build apartments with prefabricated elements, e.g., Neutra VDL. Prefabricated elements and systems offer designers and contractors significant advantages in terms of construction time, safety, environmental impact, constructability, and cost. It is important, especially in cities, that on-site construction and congestion are minimized as much as possible. Moreover, prefabrication in a factory means tighter quality control and, thus, higher quality.

A hybrid timber construction system for large buildings has been developed within the Austrian research project "Lifecycle Tower", which will guarantee minimized use of resources and energy over the full life cycle. The particular challenge of this project lay in the industrialization of the entire construction process: planning processes, batch production of the modules, fitness for purpose, logistics, and construction. The system was demonstrated for the first time in Vorarlberg, Austria, where the module construction of the eight floors took only eight days – one level each day!

Team Austria developed LISI as a prefabricated house not only for the competition requirements and demands for shipping and short construction time, but also for market availability and cost effectiveness. In the trade report of the Austrian Trade Commission, "USA Greenbuilding – Opportunities for Austrian Companies," one of the major areas of opportunity listed for Austrian companies was introducing the modern, industrial home building (Fertighaus) industry to US industry and developing high-performance building products. But in Austria the market for prefabricated buildings already exists: In 2012, about 16,000 prefabricated single-family homes were built in Austria – that constitutes nearly 30 percent of the market share for all new single-family homes built in that period.*

In the field of renovation, prefabricated elements offer further opportunities, for example: a fast renewal process with minimal disturbances for the residents, as well as creating attractive new living space in the prefabricated attic space and incorporating existing balconies into the living space. The Austrian demonstration project "Dieselweg" is often referenced on the international level as a pioneer project in this field; e.g., within the international cooperation project IEA ECBCS Annex 50, it was used as an Austrian case study. And further developments have been made: An energy-surplus renovation with prefabricated roof and façade elements is being tested in Kapfenberg within the flagship project "e80∧3-Buildings."


Raising awareness and qualified education

Smart buildings and cities also need "smart inhabitants and citizens" who are ecologically aware and forward-thinking. The best technology is useless if customers do not accept and use it. Within research and development, it is essential to take users and inhabitants into account and provide them with appropriate information. The Research and Technology Program "Building of Tomorrow" has focused on service and user aspects and supported several socio-scientific studies about the user acceptance and participation processes.

The Team Austria students meet with experts around a table duringa presentation. The development of the density of passive houses in Austria demonstrates a successful transition of user-accepted research: At the beginning of the program, in 1999, there were only 36 passive houses in Austria. Ten years later, close to 7,000 passive-house projects had been realized and Austria currently has the highest density of passive-house buildings worldwide. In the last 14 years, the Research and Technology Program "Building of Tomorrow" has facilitated further significant developments in the field of sustainable construction, such as the growth of scientific competence. A special accompanying program management has offered networking activities to use synergies of projects. While the quality of the work benefited from this program, the growth of a network within the program also contributed markedly to developing a community interested in research in the building sector (community building). With an open-access strategy, the program disseminates all research results via the program web site ( Additional channels for diffusing results are organizing topic-centered workshops and networking meetings for the project participants, and issuing research reports in bmvit's series of publications.

Austria has become a forerunner in the field of sustainable and energy-efficient construction. However, some obstacles still exist: The broad distribution of new technologies not only depends on research, industrialization, and costs, but also on proper implementation and installation by trained building technicians and craftsmen. Within a new European strategic initiative "BUILD UP Skills," the number of qualified workers across Europe will be increased to deliver renovations offering high energy performance as well as new, nearly zero-energy buildings. Thirty EU countries are working towards national roadmaps for qualifying their building workforce for the 2020 challenges. Last year, the Austrian Climate and Energy Fund started the initiative "Technical expertise" (Ausbildungsinitiative Technologiekompetenz) to boost practical-oriented education and further training in selected technological sectors, and thereby to bring results of energy research to the market.

For industrial and sustainable building, it is necessary to bridge the gap between design/planning and construction. Therefore education at all levels is essential for implementing the energy strategies necessary to change the way buildings are designed and built. The Solar Decathlon competition calls attention to collegiate education on energy-efficient and innovative technologies. According to Karin Stieldorf, competitions and hands-on experience are appropriate and successful tools to spark students' interest in subjects like building physics and engineering, which are often regarded by students as difficult and cumbersome.

The students of Team Austria will benefit in different ways from their participation in the Solar Decathlon competition: It offers a unique opportunity to acquire know-how in the fields of energy efficiency, renewable energy technologies, and sustainable building methods in a very attractive way. Moreover, it fosters collaboration among students across academic disciplines and encourages interdisciplinary approaches in developing a competitively successful house. In a nutshell, the architects of the future will gain some valuable experience while demonstrating Austrian technological leadership!


Team Austria/LISI

A project of the Vienna University of Technology (architecture, electrical engineering) in collaboration with the Austrian Institute of Technology (AIT). the Austrian University of Applied Sciences in St. Pölten and Salzburg University of Applied Sciences in Kuchl.

The author of this article hereby wishes Team Austria all the best for the "Oscar awards of solar technology in buildings" in Irvine! 


The author, Isabella Zwerger, was a visiting expert at the Office of Science & Technology at the Austrian Embassy in Washington, DC, from April to June 2013. She is responsible for research on the topic "Sustainable Buildings" in the Department of Energy and Environmental Technologies at the Austrian Federal Ministry of Transport, Innovation and Technology, and also manages the Austrian Research and Technology Program "Building of Tomorrow."



LISI | House of the Solar Decathlon Team Austria:
US Department of Energy Solar Decathlon:
Haus der Zukunft:
Austria's Smart Cities & Regions:
IG Passivhaus:
UN Hanitat:
UN Department of Economic and Social Affairs, Population Division:
AWO Branchenrepor USA Greenbuilding:
*Press Conference of the Austrian Prefab Association:
BUILD UP Skills Austria:
BUILD UP Skills:
Walkthrough of Austrian Building: