What we do Healthy buildings focus Demonstration buildings Sunlighthouse Pressbaum, Austria

Sunlighthouse – Austria's first carbon-neutral single family home 

Nine up-and-coming Austrian architects pitched their ideas for carbon-neutral home designs that kept energy consumption to a minimum without sacrificing the residents’ comfort or standard of living. Maximum daylight and solar energy were key parameters, as was an architectural profile suited to the unique landscape.

 

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Maximising light while minimising energy consumption


Built in 2010 not far from Vienna, the Sunlighthouse was Austria’s first carbon- neutral single-family home. The winning design, by Juri Troy of Hein-Troy Architekten, was a direct response to the home’s surroundings.

The Sunlighthouse is nestled in a wooded, mountainous region, on a steep, partially shaded slope that faces southeast towards the Vienna woods. The home’s sloping roof and other exciting architectural elements take full advantage of the sun to ensure maximum daylight and solar energy. With the nearby mountains casting dramatic shadows over the valley, the living area features high roof windows that bring light to the room’s centre. The kitchen and dining areas face southwest and feature numerous roof and façade windows, all positioned to provide amazing views and maximum passive solar energy gain.

Yasmin and Ludwig Dorfstetter and their two small children moved into the Sunlighthouse in March 2012 to test whether the home’s positive-energy design, combined with CO2-neutrality and ecological materials, could be realised. The project was monitored by VELUX Austria and VELUX Group’s partners at Danube University Krems and the Austrian Institute for Healthy and Ecological Building (IBO). The Sunlighthouse has since proven a major green design success, its annual energy yield from solar cells, heat pumps, solar gain and other renewable sources exceeding its annual energy consumption. 

Yasmin and Ludwig Dorfstetter and their two small children moved into the Sunlighthouse in March 2012 to test whether the home’s positive-energy design, combined with CO2-neutrality and ecological materials, could be realised. The project was monitored by VELUX Austria and VELUX Group’s partners at Danube University Krems and the Austrian Institute for Healthy and Ecological Building (IBO). The Sunlighthouse has since proven a major green design success, its annual energy yield from solar cells, heat pumps, solar gain and other renewable sources exceeding its annual energy consumption. 

Yasmin and Ludwig Dorfstetter and their two small children moved into the Sunlighthouse in March 2012 to test whether the home’s positive-energy design, combined with CO2-neutrality and ecological materials, could be realised. The project was monitored by VELUX Austria and VELUX Group’s partners at Danube University Krems and the Austrian Institute for Healthy and Ecological Building (IBO). The Sunlighthouse has since proven a major green design success, its annual energy yield from solar cells, heat pumps, solar gain and other renewable sources exceedin.

Sustainable management of natural resources has been a big part of our professional lives for a long time. So we’re excited that this experiment also gives us an opportunity to help shape the future of ecological home-building and living in our private lives."

Ludwig Dorfstetter

Photos: Adam Mørk, Michael Winkelmann

Architect: HEIN-TROY Architekten


3D model of Sunlighthouse

Key design elements and achievements

Ample daylight

The Sunlighthouse’s sloping roof and other architectural elements take full advantage of the sun and ensure maximum daylight and solar energy. 

The roof and façade windows have been strategically placed not only for stunning views but also to maximise passive solar heat gain and natural ventilation. In addition to providing an unusually high level of daylight, the numerous windows also serve as a central design element. Because the home’s total window area is equivalent to some 51% of its net floor area, very little artificial light is needed during the day, and daylight levels are balanced throughout the home’s two storeys. 

With an excellent average daylight factor of at least 5% in all living spaces, the house creates optimal conditions for healthy living.

Ventilation

Automated, intelligent control of the home’s windows is the primary source of ventilation in spring, summer and autumn. In wintertime, the Sunlighthouse uses a mechanical ventilation system with heat recovery. The home uses no energy for cooling, but stack-effect ventilation through windows, night cooling and awning blinds ensures a comfortable indoor climate throughout the warm summer months. Despite the house being oriented southeast and southwest, the Dorfstetter family did not experience any overheating due to solar gain.

A surplus of renewable energy

With its ultra-efficient brine heat pump for heating, thermal solar collectors for hot water, photovoltaic (PV) solar cell system for electricity, and energy-efficient household appliances, the house is powered exclusively by renewable energy.

The home’s PV solar cells and solar collectors actually generate more energy than the house uses. This means that after 30 years, the home will have generated as much clean energy as was used during its construction, making it truly carbon neutral.

Intelligent ventilation and temperature control

The home’s hybrid natural/mechanical ventilation system adjusts according to the temperature and weather conditions. This means that despite the region’s warm summers, Maison Air et Lumière does not require air conditioning.

Active House radar

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