The Hidden Carbon Footprint of Housing Decarbonisation Retrofits: Time to Rethink Our Approach

As the drive to decarbonise housing ramps up, it's crucial we take a closer look at the sustainability of the products we’re using in these retrofits. While improving the energy efficiency of homes is undoubtedly a positive step, the materials and products we rely on often come with their own carbon footprints, sometimes undermining the very goals we’re trying to achieve.

The Carbon Impact of External Wall Insulation

External wall insulation (EWI) is a popular solution for boosting a building's thermal efficiency. However, many traditional EWI products are far from environmentally friendly. They’re often made from petrochemicals or involve energy-intensive manufacturing processes, leading to significant carbon emissions during both production and transport.

There’s a better alternative: hemp-based insulation. Hemp is a renewable resource that actually absorbs carbon as it grows, making it a far greener choice. Research from the University of Bath found that hempcrete, a composite material made from hemp, lime, and water, can capture and store atmospheric CO2, effectively making it carbon-negative . Not only does hemp insulation reduce the carbon footprint, but it also offers great thermal performance, helping homes stay warm and energy-efficient. Despite these benefits, hemp products are frequently passed over in favour of cheaper, less sustainable options.

The Problem with Cheap Solar Products

Cheap solar products, especially those imported from China, pose another big issue. While they might be budget-friendly at the start, these products often have a shorter lifespan, meaning they’ll need replacing sooner, leading to more waste and more carbon emissions from the production and shipping of replacements. According to a report by the International Energy Agency, low-quality solar panels can degrade faster, losing efficiency within just a few years of installation .

The environmental cost of transporting these products across long distances is significant, with shipping being a major contributor to greenhouse gas emissions. On top of that, the shorter life expectancy of these products adds to the problem. Locally made solar products, though they might cost a bit more upfront, tend to last longer and come with a smaller carbon footprint due to reduced transport emissions. Research from the Carbon Trust suggests that locally sourced renewable energy products can reduce the overall carbon impact by as much as 30% compared to imported alternatives .

Onshoring and the Importance of Buying Local

The issues with traditional EWI and imported solar products highlight a broader challenge: our reliance on cheap, high-carbon materials is undermining the goals of housing decarbonisation. Bringing the production of retrofit materials back home and prioritising local procurement can go a long way in reducing the carbon footprint of these projects. By supporting local manufacturers who produce sustainable products, we can build a supply chain that’s both more resilient and kinder to the environment.

But making this shift requires more than just individual actions. As an industry, we need to question the value we place on sustainable products. Too often, the market focuses solely on upfront costs, which discourages the use of eco-friendly alternatives. This is where government support, like the Social Housing Decarbonisation Fund (SHDF), comes into play.

Rethinking the Value of Sustainability in SHDF Funding

The next round of SHDF funding is a chance to rethink how we value sustainable products. Rather than just looking at the initial cost, we should consider the long-term environmental and economic benefits of using low-carbon, locally sourced materials. This could mean offering larger grants or incentives for projects that prioritise sustainable products, or setting stricter guidelines that require the use of low-carbon materials.

We need to ask ourselves: What are we doing as an industry to ensure sustainability is given proper financial value? How can we use government funding to push for more sustainable practices? These are the questions we need to tackle if we’re serious about making progress towards truly sustainable housing.

Conclusion

Decarbonising housing isn’t just about cutting emissions; it’s also about how we go about doing it. By focusing on the carbon footprint of the materials we use and by supporting local, sustainable manufacturing, we can make sure our efforts to decarbonise housing are genuinely sustainable. As we look ahead to the next round of SHDF funding, let’s make sure we prioritise sustainability not just in our goals, but in every step of the process.