A significant proportion of UK buildings are over a century old, presenting both a challenge and an opportunity in our race to net zero. But far from being obstacles to climate action, these historic buildings are emerging as vital assets in reducing carbon emissions. From medieval cathedrals to Victorian mills, we’re discovering innovative ways to adapt our heritage buildings while preserving their character. Here’s what we’ve learned from working with Historic England and conservation officers across the country.

Since September 2024, the Centre for Sustainable Energy team have been working with Historic England to develop and deliver workshops for their staff and 71 different local authorities around the new Historic England Advice Note 18: Adapting Historic Buildings for Energy and Carbon Efficiency. We spent a great deal of time discussing how retaining and adapting the oldest housing stock in Europe is a vital part of the solution to tackling the climate emergency, and that mitigating climate change and conserving our heritage are compatible goals.

Understanding Historic England’s new approach to energy efficiency

The Historic England advice note aims to support consistent decisions on proposals to improve energy efficiency and reduce carbon emissions in historic buildings. It sets out the need for climate action, outlines the general approaches that should be adopted, considers permissions that may be needed, and explores what changes can be made through the planning process.

A shift in heritage protection

The guidance establishes starting positions on different retrofit proposals – from strong support for low-risk measures like draught-proofing windows to more nuanced approaches for complex interventions.

Crucially, it marks a shift in Historic England’s approach. For the first time, planners and conservation officers are encouraged to weigh carbon reduction as a public benefit when assessing proposals. This means looking beyond just the physical impact on listed buildings to consider wider environmental benefits. The conversation has moved from whether historic buildings should be adapted to how they can be adapted to reduce carbon emissions.

Why existing buildings matter

This guidance has wide-reaching implications, covering both homes and commercial buildings across our aging building stock. The most sustainable building is often one that already exists – its carbon footprint has already been paid for in the materials and energy used to construct it. As our energy system rapidly decarbonises towards the government’s 2030 clean energy target, the carbon locked in building materials becomes increasingly significant.

This means that as time goes by, the importance of embodied carbon (the carbon within building materials) becomes greater and greater. We can’t afford to waste either the embodied carbon in our existing buildings or the energy used to heat them.

In this context, Conservation Officers are right at the heart of the climate challenge. Their work serves a dual purpose: preserving historic buildings to protect the carbon already invested in their materials, while helping reduce the energy these buildings need. By doing both, they’re not just protecting our heritage – they’re making it easier for the UK to meet its energy needs from renewable sources.

Breaking down perceived barriers as heritage meets sustainability

The perceived divide between heritage conservation and sustainability is dissolving. When we began these workshops, we expected to encounter resistance. Instead, we found conservation officers eager to engage with climate solutions.

Finding common ground

Our work showed that we have more in common than previously thought – the question isn’t whether to adapt historic buildings, but how to do it effectively, whilst protecting what makes them special in the first place.

A key takeaway was that context is everything. Each building needs individual assessment – there’s no one-size-fits-all solution. ‘It depends’ came up a lot. We must understand how a building performs throughout the year, considering its unique characteristics and heritage value and growing climate risks, from flooding to overheating. This led us to develop a new approach. ‘Whole building, whole year approach, in a changing climate’ – moving beyond simple winter energy efficiency to comprehensive, year-round solutions.

Bridging expertise gaps

That brings us to the next takeaway and thoughts of possible next steps for Historic England. Success in adapting historic buildings requires two distinct but complementary skill sets. Conservation officers bring deep knowledge of heritage significance and impact assessment, while retrofit coordinators contribute expertise in energy efficiency and carbon reduction. But these specialties often operate in isolation.

What’s needed is a collaborative approach that brings together these different forms of expertise. Initiatives like Green Heritage Homes show how conservation officers and retrofit coordinators can work together to advise homeowners, creating solutions that respect both heritage value and climate imperatives.

New challenges, new skills

Conservation officers are now entering new territory, asked to weigh climate benefits alongside heritage preservation. This requires new partnerships with sustainability teams and climate officers, developing shared frameworks for evaluating both carbon reduction and heritage impact. Conservation Officers would benefit from further retrofit training, to be able to signpost the public to reputable sources of advice.

Historic buildings leading the way

In our whirlwind train trip around England delivering these workshops the CSE team has been fortunate to visit some fantastic venues and hear some real-life inspirational stories.

At Camden Town Hall we learnt that their heating and cooling is powered by 100% renewable sources.

At the Grade I listed Norwich Cathedral which dates from 1096 we learnt how they have already reduced their carbon footprint by 40% and are now busy planning what is hoped to be one of the largest arrays of solar PV on any Cathedral in Europe. More widely, the Church of England plans to achieve net zero emissions by 2030, an incredible ambition given the extent and heritage significance of its building stock.

In Newcastle our venue was the Universities Grade II listed Farrell Centre which showcased what can be possible with secondary glazing, mechanical ventilation with heat recovery (MVHR), and air-source heat pumps (ASHP).

But the star award perhaps goes to Cromford Mill, a World Heritage Site and Grade I listed landmark in Derbyshire, where alongside water-source heat pump, hydro power is once again being generated again at the world’s first water-powered cotton spinning mill. This demonstrates what’s possible at even the most protected UK sites.