A house’s carbon footprint decreases more than 1kg in carbon dioxide equivalent for every euro invested in sustainable building materials, finds new research from Université Libre de Bruxelles and Corvinus University of Budapest. The largest impact comes from investing in sustainable windows and external walls.

Bruno van Pottelsberghe, Rector of Corvinus University of Budapest, and Joran Douhard, PhD candidate at the Solvay Brussels School of Economics and Management of ULB, compared standard houses to sustainable versions built with more environmentally friendly materials.

The effectiveness of building materials was calculated in terms of reduced carbon dioxide equivalent emissions per euro invested. This standardises the impact of emissions, e.g. methane has 28 times the warming potential of CO₂ so 1kg methane equals 28kg CO₂eq.

The researchers found that most CO₂eq emissions come from the use of a house, rather than construction or maintenance, with 65 per cent of a house’s total carbon footprint attributed to energy used during its lifetime.

When all costs are considered, the total cost of ownership of the ‘more sustainable’ houses is 7-11 per cent higher than the standard houses. Maintenance costs are also 20 per cent and 13 per cent higher in sustainable houses, due to the more frequent replacement of sustainable materials.

“The impact of the construction sector is country-dependent, so international comparisons should be made with caution e.g. operational impact is highly dependent on heating systems, which vary a lot between regions. Nevertheless, some observations can be easily generalised to a wider EU context, such as the lower overall impact of timber frames compared to concrete structures or the imbalance between embodied and operational carbon impacts. As the methodology and data are available, interested readers will be able to easily adapt our results to local specificities,” say the researchers.

The study also shows that certain components of a house have a greater influence on carbon footprint. For example, sustainable material used for external walls and windows had the greatest impact, reducing emissions by 6kg and 3-6kg per euro respectively.

As the residential sector accounts for 17 per cent of all carbon emissions globally, this sector should be a focus point for those hoping to reduce society’s carbon footprint, and this research indicates where the use of sustainable materials could be prioritised for the greatest impact.