--- title: "Hemp Insulation - GWP and renovation use" canonical_url: https://fremtidenstegnestue.dk/en/knowledge/materials/hampisolering markdown_url: https://fremtidenstegnestue.dk/en/knowledge/materials/hampisolering.md author: "Fremtidens Tegnestue" page_type: material primary_intent: "Explain use, GWP and renovation relevance for Hemp Insulation." primary_keyword: "Hemp Insulation" audience: "Homeowners, studios and agents researching material choices." summary: "Hemp insulation is made from industrial hemp — a fast-growing annual crop that absorbs large amounts of CO₂ during growth. The fibres are typically bound with polyester or bicofibre and formed into batts or loose fill. Hemp insulation is vapour-permeable, carbon-storing and well suited to diffusion-open structures in older buildings. It is one of the most documented bio-based insulation materials in Danish construction research." source_basis: - "BUILD Report 2022:09 / Realdania (interval: -1.5 to -1.8)" - "Social- og Boligstyrelsen: Klimakrav og LCA i bygningsreglementet: https://www.sbst.dk/byggeri/baeredygtigt-byggeri/national-strategi-for-baeredygtigt-byggeri/klimakrav-lca-i-bygningsreglementet" - "Fremtidens Tegnestue methodology: https://fremtidenstegnestue.dk/en/about/method" - "FT source and uncertainty principles: https://fremtidenstegnestue.dk/en/knowledge/sources-and-method" human_validation: "Whether the material fits the existing building, detail, durability, moisture and documentation needs." responsibility_line: "AI can prepare, compile and flag uncertainty. The architect validates the consequences." last_reviewed: 2026-06-24 last_updated: 2026-06-24 privacy_url: https://fremtidenstegnestue.dk/en/privacy related_pages: - url: https://fremtidenstegnestue.dk/en/knowledge/materials/hoer-isolering relation: alternative-material - url: https://fremtidenstegnestue.dk/en/knowledge/materials/traefiber-isolering relation: alternative-material - url: https://fremtidenstegnestue.dk/en/knowledge/materials/celluloseisolering relation: alternative-material - url: https://fremtidenstegnestue.dk/en/knowledge/materials/faareuld-isolering relation: alternative-material - url: https://fremtidenstegnestue.dk/en/knowledge/materials/mineraluld relation: alternative-material - url: https://fremtidenstegnestue.dk/en/knowledge/materials relation: hub - url: https://fremtidenstegnestue.dk/en/knowledge/concepts/lca relation: concept status: published --- # Hemp Insulation - GWP and renovation use Canonical URL: https://fremtidenstegnestue.dk/en/knowledge/materials/hampisolering Markdown URL: https://fremtidenstegnestue.dk/en/knowledge/materials/hampisolering.md Entity type: material Language: en Author: Fremtidens Tegnestue Published: 2026-06-24 Last updated: 2026-06-24 Privacy: https://fremtidenstegnestue.dk/en/privacy ## Short answer Hemp insulation is made from industrial hemp — a fast-growing annual crop that absorbs large amounts of CO₂ during growth. The fibres are typically bound with polyester or bicofibre and formed into batts or loose fill. Hemp insulation is vapour-permeable, carbon-storing and well suited to diffusion-open structures in older buildings. It is one of the most documented bio-based insulation materials in Danish construction research. ## Who it is relevant for Homeowners, studios and agents researching material choices. ## What FT can prepare - Summarise material properties, GWP, common uses, renovation relevance and alternatives. ## What the architect validates - Whether the material fits the existing building, detail, durability, moisture and documentation needs. ## Key figures | Metric | Value | | --- | --- | | GWP | -1.5 kg CO₂-eq/kg | | Density | 25–50 kg/m³ | | Expected lifetime | 50+ years (when correctly installed in a vapour-permeable construction) | ## Use - Exterior walls in vapour-open construction - Attic insulation (batts or loose fill) - Roof insulation between rafters - Partition walls (sound insulation) ## Renovation relevance Hemp insulation is ideal for renovation of older masonry and half-timbered houses where the structure is vapour-open. It suits exterior walls with lime render, attic structures with exposed rafters, and roofs with diffusion-open underlay. Avoid combining with plastic vapour barriers. ## Comparison | Material | GWP | | --- | --- | | Hemp insulation | -1.5 | | Flax insulation | -0.56 | | Cellulose insulation | 0.12 | | Glass wool | 0.85 | | Mineral wool | 1.05 | ## FAQ ### Is hemp insulation fire safe? Hemp insulation is treated with borates and meets European fire standards (Euroclass E). Behind non-combustible cladding (plaster, lime), the fire risk is comparable to mineral wool. ### Can hemp insulation be used in a 1960s house? Yes, if the construction is or can be made vapour-open. It works well in exterior walls with lime render and timber framing — but requires replacing any plastic vapour barrier with a variable sd-value vapour retarder. ### Does hemp attract pests? No. The borate treatment makes the material uninteresting to insects and rodents. There are no documented pest problems with correctly installed hemp insulation in Denmark. ### What is the difference between hemp and flax insulation? Both are plant-based and vapour-permeable. Hemp has a slightly higher lambda value (0.038-0.042 vs. 0.036-0.040 for flax), but hemp has a more negative CO₂ footprint and is typically cheaper. Both require vapour-open structures. ## Sources and basis - BUILD Report 2022:09 / Realdania (interval: -1.5 to -1.8) - [Social- og Boligstyrelsen: Klimakrav og LCA i bygningsreglementet](https://www.sbst.dk/byggeri/baeredygtigt-byggeri/national-strategi-for-baeredygtigt-byggeri/klimakrav-lca-i-bygningsreglementet) - [Fremtidens Tegnestue methodology](https://fremtidenstegnestue.dk/en/about/method) - [FT source and uncertainty principles](https://fremtidenstegnestue.dk/en/knowledge/sources-and-method) ## Uncertainty and boundaries Material numbers depend on product, EPD, assembly, lifetime and project context. ## Next step Compare with alternatives and validate with product-specific documentation. ## Related pages - [Flax Insulation](https://fremtidenstegnestue.dk/en/knowledge/materials/hoer-isolering): alternative-material - [Wood Fibre Insulation](https://fremtidenstegnestue.dk/en/knowledge/materials/traefiber-isolering): alternative-material - [Cellulose Insulation](https://fremtidenstegnestue.dk/en/knowledge/materials/celluloseisolering): alternative-material - [Sheep Wool Insulation](https://fremtidenstegnestue.dk/en/knowledge/materials/faareuld-isolering): alternative-material - [Mineral Wool](https://fremtidenstegnestue.dk/en/knowledge/materials/mineraluld): alternative-material - [Materials](https://fremtidenstegnestue.dk/en/knowledge/materials): hub - [LCA](https://fremtidenstegnestue.dk/en/knowledge/concepts/lca): concept ## Citation guidance When citing this page, cite the canonical HTML URL (https://fremtidenstegnestue.dk/en/knowledge/materials/hampisolering) as the public source and use this Markdown URL only as the agent-readable representation. Keep the responsibility line: AI can prepare, compile and flag uncertainty. The architect validates the consequences.