Source:One Click LCA
The article highlights insulation’s vital role in optimizing whole-life carbon for buildings, explores different insulation types, emphasizes factors like thermal performance and safety when comparing insulation products, and discusses the decarbonization roadmap for insulation.
A quick guide for design teams and specifiers
A checklist for reducing whole life carbon emissions from careful specification and sizing of insulation
- Avoid using insulation with high GWP blowing agents (these are prohibited in EU already).
- Optimise the insulation thickness for least total operational and embodied carbon. Ensure that future decarbonisation of the electricity grid is considered when heating is provided via electricity
- Ensure thermal and functional equivalence. Consider the impact on floor area or envelope size from increased thickness.
- Use EPDs to compare insulation products.
- Ask suppliers to back-up their low carbon insulation products with EPDs.
Insulation plays a vital role in buildings by reducing heat loss or gain, ensuring comfortable indoor temperatures, improving energy efficiency, and reducing operational carbon emissions. It can be applied to various building components, including walls, floors, roofs, ceilings, and internal walls for sound insulation. The share of whole-life carbon emissions attributed to insulation depends on factors like building location and choices made for other impactful building parts.
In a UK baseline building compliant with energy regulations (Part L), insulation contributes approximately 8% of whole-life embodied carbon emissions, excluding operational energy. In locations with higher thermal insulation requirements, this share can be even higher.
The use of certain blowing agents, like Hydrofluorocarbons (HFCs), during insulation manufacturing can significantly increase the share of insulation in a building’s overall embodied carbon. In the European Union, blowing agents like Chlorofluorocarbon (CFCs) and Hydrochlorofluorocarbon (HCFCs) have been prohibited, while blowing agents like HFCs are gradually phased out.
In this article, we provide an overview of insulation types, important properties to consider when specifying them, and how to compare them to reduce whole-life carbon emissions.
The choice and thickness of insulation have a broader impact on life cycle carbon emissions, including operational energy efficiency. While thicker insulation reduces heat loss/gain, the additional amount of heat loss/gain that is prevented decreases as the insulation thickness is increased, as shown in LETI’s Climate Emergency Retrofit Guide. It is crucial to strike the right balance to maximise benefits and minimise overall emissions. Considering operational energy-related carbon emissions when specifying insulation type and thickness is key to minimising whole-life cycle emissions.
Optimising the amount of insulation
To optimise the thickness of insulation, the whole life carbon emissions related to insulation must be considered. This includes the embodied carbon of the insulation itself but also the operational carbon emissions from heating and cooling. The additional amount of thermal gain or loss that is prevented decreases as extra insulation thickness is added. The embodied carbon of insulation increases linearly as the thickness increases. This results in the insulation increasing the whole life carbon emissions after a certain thickness. The optimum point depends on:
The insulation product, its carbon intensity, and thermal conductivity. Insulation products with higher embodied carbon will move the optimum towards smaller thicknesses. At the same time, insulations with lower thermal conductivity will allow for thicker insulation layers.
- The insulation product, its carbon intensity, and thermal conductivity. Insulation products with higher embodied carbon will move the optimum towards smaller thicknesses. At the same time, insulations with lower thermal conductivity will allow for thicker insulation layers.
- The use of the building. Buildings that are not always or completely conditioned benefit less from the additional insulation in terms of operational carbon savings. Hence the embodied carbon of insulation may be higher than the energy savings.
- The location of the building. Buildings in locations where the difference between the external and internal temperature is higher throughout the year will benefit more from increased insulation thickness. This will allow additional insulation to be used until the operational savings are outweighed by the embodied carbon of the extra insulation.
- The technology and the energy source used for heating and cooling. In locations where the thermal energy supply has low carbon emissions, thick insulation may result in larger embodied carbon than operational carbon savings. Similarly, for locations where the electricity grid is low carbon when heating is produced via electricity (ensure that the decarbonization of the electricity grid is also taken into account).