In 2009, the student team from the TU Darmstadt won the international Solar Decathlon for the second time in a row. Only 20 universities can take part in this competition that is held every two years in Washington. Above all, it aims to educate the participating students about the benefits of energy efficiency, renewable energies and green building technologies and also to raise awareness among the general public for these topics.

The task is to design a fully energy-independent building with a floor area of 75 m² for habitation in 2015. The house is then judged according to various criteria, such as architecture, lighting design, technological implementation, water heating and the supply of solar energy to the net, as well as market viability and home entertainment. The unique feature of this student competition is that the individual projects are not just created on paper but they are actually built. This meant that more than 250,000 visitors were able to visit the 20 projects that had been built in Washington before they were dismantled and displayed in other cities.

The winning project, “surPLUShome”, by the team from Darmstadt headed by Prof. Manfred Hegger, Chair of Design and Energy-efficient Building, scored particularly highly in the solar gain category: based on the traditional shingle principle, almost the entire façade area was covered in photovoltaic elements. They also form a homogeneous area on the roof and so generate double the amount of energy required to operate the “surPLUShome”. This is kept to a minimum thanks to the compact dimensions of the central element, the extremely dense building shell, the use of materials in the interior that store thermal energy and controlled sun protection. An air/air heat pump generates the necessary heating and cooling energy so there are no radiators to disrupt the perception of an open room. All technical systems are controlled via a European installation bus.

In addition to energy efficiency, the designers were also dedicated to creating a house with a high degree of both technical and atmospheric comfort. The visitor experiences the inside of the cube-shaped building as a single spacious living area. Two steps down to the sleeping and bathroom area create areas with different levels of privacy. There is an open gallery above this. A so-called multifunctional body containing the open-plan kitchen, bathroom, stairs and technology divides the room lengthways. This body also contains integrated LED panels that are illuminated in all RGB colours to create varying atmospheres and moods for different occasions.

The spacious room concept is supported by further intelligent details. The bed can be stowed away behind the stairs. There is a wooden floor covering throughout the building. The bathroom is only recognisable as such at second glance. The shower tray in the entrance area to the bathroom fits flush with the floor and a rain shower is fitted in the ceiling above. The WC and washbasin are installed in niches in the multifunctional body. Two doors integrated into this body can be used to close off the area to create the necessary privacy. The project team chose sanitaryware from Duravit, selecting the washout WC and WC seat from the “Vero” range; with its elegant, high-quality design, this range enhances the atmosphere of the living area. The rectangular form and the flush-fitting seat are not immediately recognisable as sanitary objects – and, thanks to the SoftClose mechanism and soundproofing set, they are hardly audible. Vero also does its bit to help the environment: it has a flushing volume of just 4.5 l.

Thanks to smart ideas, meticulous planning and the considered use of high-quality, sustainable products, the Darmstadt-based project team has proven that energy-efficient building is more than an environmental necessity: when used correctly, it can mean a new dimension in living quality…