The Rehafutur project transformed a historic 1920 mining engineer’s home in a UNESCO World Heritage mining area in Northern France into an energy-efficient building that meets passive house standards. The project preserved cultural heritage while reducing environmental impact by integrating eco-materials and circular construction strategies.

The project faced the challenge of renovating a historic building to passive house standards while preserving its cultural and architectural heritage. The building's UNESCO designation imposed restrictions, such as maintaining its original facade and using only interior insulation. Additionally, using innovative eco-materials required overcoming technical challenges and a lack of local expertise. High upfront costs and the need to engage local stakeholders in a socioeconomically sensitive area added further complexity.

The Rehafutur project implemented a multi-pronged approach to balance conservation and innovation:

- Eco-Materials Integration: Eight eco-insulation materials, including recycled textiles (Métisse), hemp bricks, and sheep wool, were applied strategically based on their properties to optimise energy efficiency.

- Material Reuse and Repurposing: Preserved elements like century-old floorboards and tiles were carefully dismantled, refurbished, and reintegrated. Rubble was reused for interior and outdoor reconstruction needs.

- Stakeholder Training and Collaboration: On-site training sessions addressed technical challenges, such as airtightness and material application, fostering local expertise and supporting the regional economy.

- Energy Efficiency Measures: A heat recovery system complemented the eco-materials, reducing heating demand to 34 kWh/m² per year—well below regional standards for low-energy renovations.

- The selected measures led to an average energy consumption comparable to that of a 100 m² apartment despite the building offering nearly 400 m² of space.

- Important challenges arose due to the building's architectural complexity and cultural heritage preservation restrictions. The project team also had to address the limited experience and knowledge about the selected innovative sustainable materials.

- The project brought together a large interdisciplinary group of stakeholders and showed that collaboration, willingness to learn, and good communication are crucial factors in advancing circularity in current practices. Despite the challenges, the Rehafutur research project provided an effective renovation process for historical mining houses.