EFdeN VATRA is the solar house prototype which represented Romania at The Solar Decathlon Europe 21/22 in Wuppertal.

We participated in Wuppertal, Germany, where we spent 42 days of competition, where we worked with intensity and motivation to achieve the best possible results. During the competition we assembled the prototype in less than 15 days, prepared for each judging, conducted over 300 public visits involving 115,000 visitors and collected over 15,000 hours of teamwork and development opportunities.


  • 1st place – Comfort Conditions
  • 3rd place – House Functioning
  • 1st place – People’s Choice
  • Special Mention – Timber Construction Award
  • 2nd place – Blower Door Test – 0.95 ACH50
  • 1st place – Sound Insulation Test

Our vision is to create a sustainable and affordable housing model that empowers single-living people by forming a community. The intervention aims to be easily constructed and adaptable to different urban scenarios and multiple usage cycles, featuring a close connection between humans and nature.

The core concept is VATRA – the Romanian translation of the term “the Hearth” – a place full of joy, dance and stories. It is the space where the family gathered in a traditional Romanian house and also the place where the community gathered within the traditional village. We want to re-create this type of human connection through our design that also adapts to the needs of modern urban scenarios.

SDE goes urban!

The Solar Decathlon Europe (SDE) is an international competition that challenges students to design, build and operate highly efficient and innovative buildings powered by renewable energy. The competition took place in Germany in May - June 2022 and aimed to promote energy transition in urban settings, by focusing on modernizing existing building stock rather than on creating new buildings. Teams developed a solution for the challenges European cities face. In the spirit of the SDE principle ‘Design – Build – Operate’ teams built full-scale demonstrative units of their designs in Wuppertal.

EFdeN VATRA Prototype >>

Detailing and building a prototype, a representative unit for the concept proposed in the first phase.

Urban Regeneration Project >>

The conceptual proposal to vertically extend an existing building. This will not be built.


1. Architecture

EFdeN VATRA aims to create a sustainable and affordable housing model that empowers single-living people by forming a community and featuring a close connection between humans and nature.

2. Engineering & Construction

We elaborate a building concept both adapted and adaptable to its environment considering perene factors such as the local climate data, its specific site and expected usage cycles.

3. Energy Performance

VATRA is the result of a comprehensive passive design strategy with the goal of a zero-energy residential building.

4. Affordability & Viability

VATRA is more than a home, it is a hub for innovators – digital nomads – millennials. A community for people who know healthy living is community based.

5. Communication, Education & Social Awareness

Sustainability is not rocket science, it is relevant, important and achievable by anyone. It is not only for the rich, the famous or the sophisticated but for everyone to care about and strive towards.

6. Sustainability

EFdeN’s efforts revolve around creating a circularity strategy that can and will involve as many components that can bring a positive impact on the environment through as many life-cycles as possible.

7. Comfort

A functional building is bound to constantly react to the changes from both its exterior and interior environments. Its interior comfort conditions, energy consumption, durability and ultimately its added value are all dependent on its ability to meet the dynamic character of its demands.

8. House Functioning

Appliances are programmed and automated so that their use coincides with the maximum production of photovoltaic panels and outside the peak consumption in the network.

9. Urban Mobility

The outdoor area of Cafe Ada is equipped with a VATRA SWAPPING STATION, where people could park their bikes or just stop to grab a new battery without waiting for the e-bike to charge.

10. Innovation

We propose the approach of using a design algorithm, inspired by Bin Packing algorithms in order to generate different kinds of site optimal space configurations using 3 house modules.

Back to top of page