MoreEnergy is a term used in building design to describe a structure that produces more energy than it uses. The term was coined in 1994 by Rolf Disch when building his private residence, the Heliotrope as the first PlusEnergy house in the world. Disch Then Went there to refine the concepts Involved with Several more projects built by His company Rolf Disch Solar Architecturein order to promote PlusEnergy for residential, commercial and retail spaces. Disch maintains that MoreEnergy is more than just a method of producing environmentally-friendly housing, but also an integrated ecological and architectural concept. As such, PlusEnergy is intended to be superior to low-energy or zero-energy designs such as those of Passivhaus .

Technical approach

The PlusEnergy approach uses a variety of techniques to produce more energy than it consumes. A typical example is to capture heat during the day in order to reduce the need to generate heat over night. This is achieved using a wide range of light and energy sources. Triple-paned windows ( U-value = 0.7) trap this heat inside, and the addition of the heat insulation means the structure is already warm in the evening and therefore needs less heating. In the Sun Ship , 60,000 sq ft (5,600 m 2) commercial, retail and residential PlusEnergy structure, techniques such as phase changes in the walls and vacuum insulation are also used. This permits maximum availability of floor space without compromising efficient insulation.

Social and community aspects

An important part of the PlusEnergy approach that differentiates it from similar concepts is that the owner of a more energy-efficient building should be able to live and work comfortably in it without sacrificing lifestyle or normal living standards. For example, solar panels are made aesthetically pleasing so that they are integrated into the facade of the structure. This reflects more on energy planning and integration, with aspects of transportation, water management and communication being part of the design.

PlusEnergy design also emphasizes the importance of sustainable development on communities in general. An energy-efficient community is seen as a positive source of identification and community pride. Rolf Disch says he attracts a high quality of creative, innovative undertakings and creative work places through his designs. Ecological urban planning techniques like traffic management, attractive walkways, bicycle routes and connections to public transportation are all part of the PlusEnergy ideal. At the Solar Settlement for example, tenants and owners, and the neighborhood has an extensive car-free zone with many public transportation connections.

Example projects


Built in 1994 Rolf Disch in Freiburg , the Heliotrope is claimed by its designer to be the first building in the world to create more energy than it uses and CO 2 neutral. The structure rotates to the sun, which allows it to use a large amount of natural sunlight and warmth during the day. Several different energy generation technologies are used in the building, including a 603 sq ft (56.0 m 2 ) dual-axis solar photovoltaic tracking panel , a geothermal heat exchanger , a combined heat and power unit (CHP) andsolar-thermal balcony railing to provide heat and warm water. These in combination with the large amounts of Heliotrope to produce between four and six times its energy use depending on the time of year. The building is also equipped with a gray-water cleaning system and built-in waste composting.

After the success of Freiburg’s Heliotrope, Hansgrohe contracted by Rolf Disch Solar Architecture to design and build another Heliotrope to be used as a center and showroom in Offenburg , Germany. A third heliotrope was then built in Hilpoltstein , Bavaria to be used as a technical dental laboratory.

  • Heliotrope in Freiburg

  • Bird’s eye view of the Heliotrope in Freiburg

  • Heliotrope-Hotel Schloss Waretenstein

Solar Settlement

Main article: Solar Settlement

With the success of the Heliotrope, Rolf Disch Solar Architecture applied their PlusEnergy concept to mass residential production in the form of a community development of 50 PlusEnergy houses. The project, called Solar Settlement , won 2002 House of the Year, 2002 Residential PV Solar Integration Award, and Germany’s Most Beautiful Housing Community, 2006. Built between 2000 and 2005 in the Vauban quarter of Freiburg , the Solar Settlement is intended as an example of Disch’s vision of a “fundamental environmental imperative”. As of 2011, the homes have had more than 5,000 Euros ($ 5,600) of surplus energy a year, from which the owners of the houses have benefitted.

Made from Black Forest timber, the wood interior and natural lighting provide for happily bed spaces and a natural flow from room to room. The tenants at the Solar Settlement claim in their living standards, and they have benefitted environmentally and economically.

Sun Ship

Main article: Sun Ship (building)

The Sun Ship, located next to the Solar Settlement in Freiburg, uses its 60,000 sq ft (5,600 m 2 ) for retail, commercial and residential space. The Sun Ship houses on the first floor, offices and work spaces on the 2nd and 4th floors, and 9 penthouses on its roof. Notable aspects of the building are its vacuum insulated walls, ventilation with 95% heat recovery, triple paned windows, and solar-paneled facade.

As the first positive energy office building worldwide, the Sun Ship exhibits not only high energy efficiency but also a pleasant environment to work in. The office spaces are flanked on both sides by natural light and by the light of artificial light. In addition to the office and retail space, two conference rooms provide space for readings, meetings and a showroom.


  • 2008 German Sustainability Award
  • 2005 Wuppertal Energy and Environment Prize
  • 2003 Global Energy Award
  • 2002 European Solar Prize
  • 2001 Photovoltaic Architecture Prize Baden-Württemberg

Further detail on projects

  • Heliotrope , Vauban, Freiburg , 1994
  • Heliotrope, Offenburg , 1994
  • Heliotrope, Hilpoltstein , 1995
  • Solar Settlement , Vauban, Freiburg , 2002
  • Sun Ship , Vauban, Freiburg , 2004

About the author


View all posts