There are a wide range of insulation materials now available on the market, from oil-derived foam products to natural products such as hemp or sheep’s wool
The specification of insulation can be key to reducing carbon emissions, energy use and achieving Part L. In respect of this, increasing energy efficiency requirements dictate higher levels of insulation. Manufacturers’ detailed
performance data requires close scrutiny.
There are a wide range of insulation materials now available on the market, from oil-derived foam products to natural products such as hemp or sheep’s wool.
It is the material from which the product is derived that has the most impact on its embodied energy. Some argue that for insulation the energy conserved through its use far outweighs the energy used in its manufacture, and therefore embodied energy is less important for insulation materials. But if low embodied energy is a concern, consider more natural materials which have been through less processing.
Breathable insulation materials, such as hemp, wood fibre and sheep’s wool are well suited to situations where moisture control or air quality may be an issue. However, these can require deeper levels of insulation to achieve the required u-values.
Comparison of alternative insulation types
|Cellulose fibre||Glass wool fibre||Rock mineral wool foam||Extruded polystyrene||Expanded polystyrene||Polyurethane foam||Aerogel blanket|
|Insulation thicknesses required to achieve 0.2W/m2K||235mm||220mm||210mm||190mm||180mm||150mm||75mm|
|Thermal conductivity||0.038 -0.040W/m°K||0.031 - 0.040W/m°K||0.031 - 0.040W/m°K||0.028 - 0.036W/m°K||0.032 - 0.040W/m°K||0.022 - 0.028W/m°K||0.013W/m°K|
|Density||32kg/m3||16-24 kg/m3||24-40 kg/m3||30 kg/m3||15-35 kg/m3||30-40 kg/m3||180 kg/m3|
|Recycled content||Typically 90%||Typically 30-60%||23%||none||none|
|Crade to Grave embodied energy||16.64 MJ/kg||49.6 MJ/kg||16.8 MJ/kg||95 MJ/kg||108 MJ/kg||101 MJ/kg||53 MJ/kg|