Sustainability Report

The project minimizes embodied carbon through its construction. The entire above-ground structure is primarily wood (timber frames, cellulose insulation, fir cladding, wood windows/doors, glueless timber slabs), a carbon-sequestering material. Furthermore, the excellent OI3-Klassifizierung ecological indicator (OI3-Ic = 1.23) for building components confirms a very low environmental impact from materials, aligning with a low-carbon design. 

• Timber-First Construction: The "complete Construction of the Building over the ground is wood," including wooden frame walls, fir interior cladding, and complete wood-framed windows and doors. The slabs are "glueless, board stack blanket with acoustic millings." This extensive use of timber, a renewable and carbon-sequestering material, is a primary embodied carbon reduction strategy.

• Cellulose Insulation: Walls are insulated with "cellulose insulation," a material typically made from recycled paper products, which has a lower embodied energy compared to many conventional insulation materials.

• Untreated Fir Façade: The exterior features an "untreated fir façade" that develops a natural patina over time. Avoiding chemical treatments or paints reduces the embodied carbon associated with manufacturing and applying such finishes.

• Natural Interior Materials: Inside, "clay plaster, solid wood elements, and natural stone" are used. These natural materials generally have lower embodied carbon compared to highly processed synthetic alternatives, and their ability to "age gracefully" implies durability, reducing future replacement needs.

• Small Footprint: The extension was designed with a very small footprint of 42 square meters, directly minimizing the overall quantity of materials needed for construction.

The project employs advanced strategies to minimize operational emissions and energy consumption:

• High-Efficiency Heat Pump System: The old oil heating system of the existing building was replaced with a brine-to-water heat pump with deep boreholes. This new system provides both heating in winter and cooling in summer, ensuring a pleasant indoor climate year-round with highly efficient, renewable energy.

• On-Site Renewable Energy Generation by a 7kWp photovoltaic (PV) system: It is located on the roof of the new extension, generating clean electricity on-site and significantly reducing reliance on grid power. The project significantly reduces operational carbon by replacing an old oil heating system with a high-efficiency brine-to-water heat pump for both heating and cooling. This combination of highly efficient, renewable-powered HVAC and direct renewable electricity generation dramatically minimizes reliance on external energy grids and fossil fuels, achieving well beyond a 30% reduction in emissions compared to a conventional average

• Passive Climate Regulation (Clay Plaster): Clay plaster is used in bathrooms and toilets for "moisture regulation." In combination with a reed substructure, the 2-3cm thick clay layer "provides a super Climate," even during hot showers. This natural material helps regulate indoor humidity and temperature, contributing to comfort and potentially reducing the need for active climate control systems.

• High-Performance Envelope: The wooden frame walls with cellulose insulation, ventilated vertical fir cladding (façade), and complete wood-framed windows and doors contribute to a well-insulated and thermally efficient building envelope, minimizing heat loss in winter and heat gain in summer.

The design incorporates strategies that reduce service and maintenance emissions over the building's lifespan:

• Durable, Patinating Materials: The "untreated fir façade develops a black-gray patina over the years, gently integrating the building into the landscape." This natural aging process means the facade does not require painting or frequent treatment, reducing maintenance costs and associated emissions.

• Natural, Gracefully Aging Interiors: "Clay plaster, solid wood elements, and natural stone" are chosen because they "age gracefully, with their worn surfaces telling the story of the house over time." This eliminates the need for frequent re-finishing or replacement, lowering long-term maintenance impact.

• Efficient and Reliable Building Services: The new brine-to-water heat pump system is a modern, efficient technology, likely designed for long-term reliability and lower maintenance compared to an old oil heating system. The repurposing of the oil tank room also avoids new construction for storage.