How we calculate the CO₂ estimate

The 350.4-tonne figure combines two quantities in an illustrative Bloom 190 scenario over 50 years: 294.1 tonnes of modelled avoided operational CO₂ and 56.3 tonnes of CO₂ stored in the assessed panels.

Operational scenario: 294.1 tonnes

The model assumes 190 m² of nominal model area, a reference energy demand of 150 kWh/m²/year, a BIOBUILDS scenario of 30 kWh/m²/year, and a 25% reduction in the calculated energy saving.

(150 − 30) × 0.75 × 190 × 50 = 855,000 kWh
855,000 × 0.344 kg CO₂/kWh = 294,120 kg CO₂

The 0.344 factor is the German electricity-generation mix’s direct CO₂ factor for 2025, reported by the Umweltbundesamt. It is held constant in this illustration. This is an assumed scenario, not a forecast of future grid emissions or a measurement of a particular home. Actual heated area, energy sources, heating-system efficiency, climate and use change the result.

Panel carbon stock: 56.3 tonnes

The model uses external dimensions of 12.59 m × 15.09 m × 3.30 m, assumes openings occupy 20% of the wall area, and uses 190 m² each for floor and roof.

Wall area: 2 × (12.59 + 15.09) × 3.30 × 0.80 = 146.1504 m²
Stored CO₂: (146.1504 × 36.31 + 380 × 26.44) × 44/12 = 56,297.7 kg

The panel carbon contents of 36.31 and 26.44 kg C/m² come from HUB-0050, external walls, and HUB-0048, slabs. They apply to the assemblies declared in those EPDs.

Insulation and scope

The EPDs assess the earlier cellulose-insulated assemblies. Current homes use STEICO wood-fibre insulation. The material principles are similar, but calculated impacts can differ. The external-wall result of −101 kg CO₂e/m² applies to the declared assembly in production stages A1–A3, not automatically to the current wall.

Carbon held in panels is a stock, not an avoided emission. Later release or recovery depends on the end-of-life scenario. The sum, 294.120 + 56.2977 = 350.4177 tonnes, rounds to 350.4 tonnes. Adding these quantities does not establish verified net savings over the whole building’s lifecycle. Construction, other components, maintenance and end of life require a consistent whole-building assessment for that claim.

Method recorded on 02.10.2026. Explanation updated on 12.10.2026.