CO₂ Calculator
Estimate in seconds the CO₂ captured and the energy saved by your hemp-lime project.
The plant-based carbon
in your walls.
How much plant-based carbon will the hemp-lime walls of your home hold?
An estimate in a few seconds.
Enter your project data
in the walls (estimate)
building class requires a complete assessment
Estimates based on the manufacturer’s declaration, available test reports and HES Group technical literature. The hemp-lime wall area is estimated from the home’s floor area using a geometric model (perimeter, storeys, floor height, openings). Method: according to the manufacturer's datasheet each m³ of cast HES-mix contains about 100 kg of dry hemp shiv; conservatively, net of waste and moisture, we count 94. Dry hemp holds about 1.6 kg of CO₂ per kg as plant-based carbon. Hence 94 × 1.6 ≈ 150 kg of CO₂ per m³ (range 125-175). Sources and formula below. The calculation counts only the hemp-lime walls. It is carbon contained in the material, not a climate balance of the building: it is not CO₂ removed, avoided or offset, and it is not verified by third parties. Indicative values —
Formula and sources. Volume = wall area × thickness; wall area = perimeter × storeys × 3.0 m, minus 22% openings; storeys: 1 up to 120 m², 2 up to 400 m², then 3; perimeter ≈ 4.4 × √(floor area ÷ storeys). Hemp Eco Systems SA, Technische Datafiche HES-mix (2015): 20 kg of hemp shiv, 25 kg of hydrated lime and 3 kg of HES-plus per batch, density about 240 kg/m³, hence about 100 kg of shiv per m³. Boutin M.-P. et al. (2006), Étude des caractéristiques environnementales du chanvre par l’analyse de son cycle de vie, INRA: 1.6 kg of CO₂ per kg of shiv. Pretot S., Collet F., Garnier C. (2014), Life cycle assessment of a hemp concrete wall, Building and Environment 72: about 1.7. Senini EPD «Bio Beton Jet», EPDITALY0347 (2022, EN 15804+A2), hemp-lime biocomposite: 16.5 kg of carbon in 33 kg of shiv, i.e. 1.83 kg of CO₂ per kg (cited only for the carbon content of the shiv).