As buildings become more energy efficient in use, the balance of carbon impacts is changing. Operational carbon (the emissions from running a building) is reducing, while embodied carbon (the emissions associated with materials and construction) is becoming increasingly significant.
This shift places far greater importance on material choice — particularly for products used across almost every building type, such as insulation.
Operational carbon vs embodied carbon
Operational carbon refers to the emissions created through heating, cooling and lighting a building over its lifetime.
Embodied carbon refers to the emissions associated with producing, transporting, and installing building materials, as well as their eventual disposal or reuse.
As regulations, standards and design practices continue to drive down operational energy demand, embodied carbon represents a growing proportion of a building’s total carbon footprint. This makes accurate, comparable material data essential.
What is an Environmental Product Declaration (EPD)?
An Environmental Product Declaration (EPD) is a third‑party verified document that reports the environmental impacts of a product using a standardised methodology. In the construction sector, EPDs are produced in accordance with EN 15804, allowing designers and specifiers to compare materials on a consistent, like‑for‑like basis.
An EPD is the independently verified version of a Life Cycle Assessment (LCA). While an LCA is the underlying analysis, an EPD provides assurance that the data has been reviewed and verified by an external body.
Sisalwool’s EPD data is published through the International EPD System, providing transparent and credible environmental information to support low‑carbon decision‑making.
Material choices and embodied carbon
Embodied carbon is heavily influenced by the type of raw materials used.
Unlike synthetic fibres, natural fibres store biogenic carbon during growth. When those fibres are used in construction products, that stored carbon remains locked into the material for the duration of its service life.
Sisalwool insulation uses mostly recycled and renewable natural fibres, including sisal and recycled wool. This approach avoids emissions associated with virgin, energy‑intensive raw materials while making use of fibres that would otherwise be discarded.
Understanding Sisalwool’s EPD data
As part of Sisalwool’s EPD development, a Life Cycle Assessment was carried out in line with recognised standards to quantify the embodied carbon associated with the product.
The EPD reports environmental impacts within clearly defined life‑cycle stages, including raw material sourcing, processing, manufacture and transport, using the EN 15804 framework. Presenting results in this way ensures that the data can be understood, scrutinised, and compared consistently with other construction products.
The results demonstrate a very low embodied carbon profile for Sisalwool insulation, reflecting both the carbon stored within natural fibres and the use of recycled materials within the product.
Beyond carbon metrics: building fabric performance
While embodied carbon data is essential, it does not exist in isolation from building performance.
Sisalwool is vapour‑open, meaning it allows moisture to move through the building fabric rather than trapping it. This supports moisture‑safe construction and helps maintain the condition of surrounding materials, particularly in retrofit and traditional buildings.
By supporting stable building fabric conditions, vapour‑open insulation can help reduce the likelihood of moisture‑related defects and premature material replacement — factors that would otherwise increase embodied carbon over a building’s life.
Why transparency matters
Reliable environmental data allows designers, clients and contractors to make informed decisions based on evidence rather than assumptions.
Publishing EPD‑aligned data enables:
- Clear understanding of a material’s embodied carbon
- Meaningful comparison between insulation options
- Better integration of material choices into whole‑building carbon assessments
For Sisalwool, publishing EPD‑aligned data is part of a broader commitment to transparency, continuous improvement, and building materials that are better for people and the planet.
Looking ahead
EPDs are not an endpoint. They are a foundation for ongoing improvement, informed design, and more responsible material selection.
As expectations around carbon reporting continue to rise, clear and verified environmental data will play an increasingly central role in how buildings are designed, specified and delivered.
Review our EPDs here:
Sisalwool 50mm & 100mm
Sisalwool Loftroll
the sisalwool collection
