- 13. March 2025
Energy renovation requires materials with a low CO₂ footprint
Energirenovation is about more than just insulation and new windows if you truly want to reduce climate impact. By using materials with a low CO₂ footprint, both operational energy and resource consumption can be reduced, but this simultaneously requires increased attention to the properties of the materials and where and how they are best utilized.
This is the focus of an article in the Danish newspaper Bygge- & Anlægsavisen featuring Danish Technological Institute, a partner in EASI ZERo. Read a translation here:
25% of the Danish building stock is from a time when requirements for energy efficiency were minimal, which makes energy optimization and retrofitting of existing buildings an important step in reducing the climate impact of construction. And there is considerable room for improvement regarding energy efficiency in Denmark, where the building stock accounts for more than 40% of total energy consumption.
If energy renovation is carried out using materials with a low climate impact, such as renewable, bio-based materials, not only is energy consumption reduced, but so is the embedded CO₂ in the materials.
Less climate-impacting materials for retrofitting
It's not new that we are seeing examples in construction projects where materials such as paper and wood fiber insulation, and hemp are used for energy renovations and retrofitting. And now we are also beginning to see other biobased insulation materials like straw, flax, and mycelium emerging, which are expected to play a role in the future retrofitting of older buildings to reduce the CO₂ footprint.
- Energy renovation is a key for the green transition, and it should ideally be carried out with the lowest possible impact on the planet. That is why new solutions with low climate and environmental impact are being actively developed. One example is the EASI ZERo project, where our goal is to create a complete package of materials and components for energy optimization of existing buildings. Here, we are looking to optimize the performance of, among other things, wood fiber insulation and a number of other technologies that combine sustainability with high performance, says Thue Trofod, who is business manager at Danish Technological Institute and EASI ZERo partner .
EASI ZERo is a European development project supported by the EU, involving a consortium of 16 partners representing the entire value chain in renovation.
- The project is a little over halfway, and we are already seeing promising results for a number of materials, including wood fiber insulation. Here, we see an improvement in both technical properties and in terms of increased sustainability, says Thue Trofod, who is involved in material development and documentation in the project.
Barriers to the use of biobased materials
Working with biobased materials is not ‘plug and play’, and there are quite a few things to consider before you can use these, in themselves, more environmentally friendly materials.
- There are strict requirements for the safety of materials used in construction, and it is no different when it comes to biogenic materials. One of the biggest challenges is meeting strict fire safety requirements, as biobased materials have a lower natural fire resistance compared to traditional materials such as concrete and steel, says Thue Trofod and continues:
- The moisture-technical properties are also a critical factor that cannot be overlooked, as biobased materials behave differently from mineral materials when it comes to moisture, and the materials must therefore be handled correctly to avoid issues with mold, fungus, and reduced durability.
Holistic approach
It is precisely important to be aware of the properties of the materials, adds Center Director Thor Hansen, Danish Technological Institute, who works with quality in construction:
- Biobased materials are interesting and probably a must in the green transition, but like all building materials, they have different material properties and robustness against, for example, moisture. It is therefore important to pay attention to the material’s properties compared to traditional materials. And that also means you can’t ‘blindly’ replace materials one-to-one, but must instead consider what the material is exposed to in the given construction, where, for example, there may be an increased risk of moisture exposure, says Thor Hansen.
But according to Thor Hansen, there is good reason to be optimistic about biobased materials also making their way into the energy optimization of our buildings. He also appeals that it is important not to get tunnel vision on the individual qualities of materials and forget the most important thing: That they must work in a larger interplay with different materials that have different properties.
And it only gets more complicated when discussing renovation and transformation of buildings, where new or reused materials must interact with existing materials in the construction:
- It is important that we do not look only at each individual material in isolation, but instead consider how they function together. The materials themselves may be good, but what is crucial is how they work in context with other materials. However, this should not prevent us from testing and trying out new materials, but rather be a call to adopt a holistic view of each material and not forget building physics when they are to be used in construction, emphasizes Thor Hansen, adding that perhaps in the future we won’t need to build the same way all around the house.