For decades, the UK has added about 1% to its existing building stock and refurbished about twice that each year. US figures are similar. Now we have some 27 million existing homes and a target for them to be net zero carbon by 2050. That requires a million domestic retrofits a year.
There is plenty of focus on the sustainability and carbon impact of the new houses. But what about existing stock? American architect and former President of the American Institute of Architects, Carl Elefante, once self-deprecatingly described the existing stock as the ‘elephant in the room’.
He argues passionately that the greenest buildings are those that already exist. Buildings account for about 40% of global carbon emissions. At present, about a quarter of that is due to materials and construction activity and three-quarters to operational energy.
Replacing a building carries a considerable carbon cost compared with retaining and refurbishing it. And, as operational energy is reduced by more efficient systems, improved building controls and perhaps greater management focus on controlling energy bills, the balance will swing further towards embodied carbon.
The more we can re-use, repurpose and refurbish our existing buildings, the better for our carbon ambitions. But there is much more to this than carbon. One of the greatest concerns about the net zero agenda is that it is perceived as a cost, a burden on the economy. ‘Without this obsession with being green, just think what our economy could do!’
But regenerating and updating our existing buildings is not a burden. It is a huge growth opportunity. Every town or city has abandoned or unoccupied buildings that could be better used. There is ample scope to stimulate years of growth. Older buildings that are energy hogs need refurbishing to reduce their demand for energy by fabric improvements and new heating systems.
If we are concerned about the appeal of those projects and our profession to younger engineers – and architects and other professionals – there is plenty of engineering and architecture in refurbishing existing buildings. These need to be maintained, preserved and adapted for the present, which is often more challenging than clearing the site and starting again. And yet, as Elefante has argued, existing buildings are a resource to be used purposefully and managed.
The more we can re-use, repurpose and refurbish our existing buildings, the better for our carbon ambitions
The launch at the beginning of March of the National Retrofit Hub, which aims to enable the delivery of housing retrofit at significant scale across our housing stock, marks a significant and long overdue step forward in addressing the elephant of existing housing.
The benefits of retrofitting buildings are many. They include lower energy bills, peak load on the grid and CO2 emissions and therefore reduce total investment needed to decarbonise the grid. Reducing aggregate and peak grid demand enhances our energy security.
A major retrofit programme offers nationwide job creation and growth and a stimulus to innovation in the technologies that are needed to improve the energy performance of our housing stock, especially in the hard-to-heat sector.
The benefits go beyond the building and energy sectors. Retrofit should make homes cheaper to run, improve comfort and reduce burdens on the NHS. Retrofitting existing buildings is probably one of the smartest smart-growth strategies available, with the potential to deliver energy efficiency, carbon reductions and health benefits.
But if it were that easy we would be doing it now and not need a national initiative like the hub. While we have the knowledge and expertise to deliver effective retrofits, they are not widely available and the principles of safe, healthy, well-ventilated and condensation-free energy efficient homes are nowhere near as extensively distributed as they need to be.
Delivering that knowledge, providing training and building confidence through appropriate competence and certification arrangements is complex and needs coordination to avoid duplication. It is also vital to avoid condensation and poorly ventilated homes, with the dangers they pose.
But a common understanding across the industry will enable accelerated progress, improved outcomes and foster effective innovation. Retrofitting our existing buildings is critical to a healthy net zero future.