Modern history – retrofitting old buildings for a carbon neutral future

Duncan Wilson, Chief Executive at Heritage UK, says retrofitting historic buildings can help meet net-zero targets.

To meet the UK Government’s target of being carbon neutral by 2050, we know we must recycle and reuse our existing historic buildings, rather than demolishing and building new, so that embodied CO₂ emissions are not released through demolition. Doing so not only produces millions of tonnes of waste – three fifths of all waste produced in the UK every year comes from construction, demolition and excavation – but building new has high energy costs and absorbs large quantities of resources.

While considering how we recycle and reuse our existing buildings is important, we must acknowledge that buildings – including homes – are the third largest producers of carbon emissions in the UK today, with homes alone accounting for 13%.

As England has one of the oldest building stocks in Europe – with a fifth of all homes being over a century old – we need to reduce the carbon emissions from our historic buildings. However, this is a complex process as every building performs, and is used, differently by its occupants and has its own set of unique characteristics.

The Heritage Counts report, published this year by Historic England on behalf of the Historic Environment Forum, shows that carefully retrofitting our historic homes could save up to 84% in carbon emissions. The aim of this is to support and empower the people who look after our historic buildings. We know that many homeowners want to do the right thing, but might not know where to start. The report is a step towards helping historic building owners to better understand the available options in an often complicated market.

Modelled examples reveal that carbon emissions can be reduced by up to 84% in a detached Victorian home, 62% in a Georgian home, 58% in a 1900s terrace, 56% in a Victorian semi-detached and 54% in a Victorian terrace.

But how can these savings best be achieved in a way that respects the character which makes an historic home special? Unfortunately, there is no simple one-size-fits-all solution to reduce the carbon footprints of historic homes. They vary from building to building, with type, materials and condition each having an impact. However, Sir David Attenborough’s recent advice applies here, as it does to much of our behaviour when it comes to tackling the climate crisis, “don’t waste electricity, don’t waste paper, don’t waste food. Live the way you want to live but just don’t waste”. The top line advice we can give is to consider the retrofit option that avoids wasting energy thus minimising carbon emissions. This means keeping on top of repair and maintenance to improve the condition of its existing materials. It also means planning well for a retrofit, using the building elements already available, using fewer new materials with large carbon footprints – often imported from abroad – and instead use natural, durable and recycled materials.

Planning well for a retrofit means considering the building as a whole. Understanding its significance and the factors that impact its energy use are important when devising an approach to reducing emissions.

There are various options available to building owners, which have differing impacts on carbon emissions. Smaller acts such as adding secondary glazing to single glazed windows is one of the most cost-effective measures for reducing emissions and can reduce annual CO₂ emissions by up to 7%. Similarly, draughtproofing windows and doors is quick and relatively low cost yet still has a tangible impact on emissions. Even well-fitted roller blinds can reduce annual CO₂ emissions by up to 2.5%.

Bigger acts such as adding insulation where there is currently none can result in annual emissions savings of between 16-18%. Replacing an inefficient E-rated boiler at the end of its life with a more efficient boiler or a lower carbon alternative heating source, such as air source heat pumps, could make savings in yearly emissions equivalent to those produced from driving 21 small petrol cars along the entire M1 motorway in the UK.

It must also not be forgotten that people will play a crucial role in our low-carbon future, so behaviour changes will be as important as careful retrofit. In particular, the way homes are heated has a direct impact on energy use. The simple act of turning down our thermostats from 21°C to 20°C and having the heating on for an hour less each day could see an almost 10% reduction in our annual household CO₂ emissions.

The message from this research is clear – we can make a difference and with set net-zero targets for 2050, we all have a part to play.