With COP26 happening and having spent my half term reading Greta & the Giants to my girls, we all need to take control. As Greta says in the book, “Climate change is the biggest crisis humans have ever faced.” If we’re going to save our planet for future generations, we need long-term thinking—we need to “look after the things that matter” and “mend what is broken instead of buying new”.
Looking around at the end of 2021, we see high streets full of empty shops and deserted business parks, coupled with a post-pandemic demand for space and suburban life. Our country is continuously growing, and every sector is seeking new sites for buildings. The answer seems obvious: rather than building new facilities on ever-diminishing empty space, our starting point for a more sustainable future should be to refurbish and repurpose what we have. As architects, we can not only give new life to old buildings, but target low-energy design, reduce carbon, and improve the mental health and wellbeing of occupants.
Buildings have an impact on carbon emissions in two ways. First is construction: building materials create carbon emissions at every stage of the supply chain process, from extracting the raw materials to delivering them to a site. Together with the on-site process of actually constructing the building, these emissions make up the building’s embodied carbon. Then there’s the operational or in-use carbon: the additional carbon emitted throughout a building’s lifetime, from day-to-day activities such as heating, lighting and cooking.
Typically, the ratio of carbon emissions across a commercial building’s lifetime will be 30% embodied, 70% in-use. For a domestic building this is likely to be closer to 50/50, as commercial uses tend to be more energy-intensive.
When we make the choice to demolish and rebuild – when we choose not to refurbish existing buildings – we make the choice to worsen the climate crisis. We choose to extract more raw materials, to increase carbon emissions, to increase waste. Choosing to retrofit saves much of the embodied carbon within an existing building. As architects never tire of pointing out, “The greenest building is the building that already exists.”
That said, it’s worth bearing in mind that existing buildings are rarely as efficient as new buildings. At the same time as we reduce energy use and carbon emissions from construction, we need to address the issue of our existing stock’s operational carbon. The UK has pledged to reduce carbon emissions by 80% by 2050 (in relation to 1990 levels), but 80% of what will be our built environment in 2050 already exists. This means that we need to make retrofitting our existing buildings to improve their energy performance a key part of our strategy.
The way a building is designed doesn’t just impact its surrounding environment: it also and more obviously affects its own internal environment. Bringing new life to old buildings allows us to focus on fabric first: we can upgrade and increase the performance of insulation, windows and airtightness.
Improvements like these not only help reduce energy loss, but make a positive difference in the radiant temperatures of walls. For those inside the building, spaces become more comfortable to occupy, with a more controlled temperature. We can also renew or upgrade services such as the ventilation, water supply and boilers, reducing carbon and improving air quality.
It’s reasons like these that mean we have to think more widely when considering the value for money of retrofitting a building. The cost of retrofit against the payback of energy savings don’t provide a financial incentive when looked at in isolation – but when we consider the positive health and wellbeing outcomes, and the associated financial (and other, more important) benefits these bring, an obvious business case for retrofitting emerges.
For instance, there are the health benefits of reducing damp, and providing a solution to fuel poverty. Air quality is a particularly relevant topic as the COVID pandemic continues, and improving ventilation can have an enormous impact on this, using techniques such as MVHR (mechanical ventilation with heat recovery). This can be particularly important in schools where CO2 levels are a concern, and issues are exacerbated in winter when the windows are rarely opened.
Last week, LETI released their Climate Emergency Retrofit Guide, which shows how we can retrofit our homes to make them fit for the future and support the UK’s net-zero targets. This includes targets for energy use in existing homes, and practical guidance on how to achieve them.
This guide is a must-read, and provides real, pragmatic advice on how we can achieve a more sustainable future. Our existing buildings have a huge impact on our carbon emissions, and following LETI’s approach could create massive carbon savings.
Architects have an important role to play in leading by example, and using our unique perspective to demonstrate the benefits of retrofitting rather than building anew. But a cohesive approach requires the buy-in and expertise of the entire industry – from clients and developers to specialist subcontractors. The eyes of the world are on the built environment, and the time to act is now.
Schools Sector Director
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