Decarbonising heritage properties

Britain has some of the world’s oldest building stock, which in many places defines our heritage and history. This is evident across our university campuses. However, with the built environment being responsible for nearly 40% of carbon emissions and an increasing focus on emissions reduction to reach net zero targets, attention must now be given to how the environmental performance of these properties can be improved.  

“The greenest building is the one that already exists”, identified Carl Elefante, former president of the American Institute of Architects. But how can universities as heritage property owners address the challenges that decarbonisation presents?

Whole building approach

When looking to decarbonise your heritage property, a whole building approach is fundamental. You must understand your building in context – the environmental impact and performance of each building will be different and will be affected by its location and orientation, the building fabric, the services and equipment it uses and its occupiers.

Successful decarbonisation will require cultural and social solutions, alongside technical innovations. The AUDE Decarbonisation Guide provides detailed advice on preparing decarbonisation plans. Start by analysing and if necessary, changing, the way the building is occupied, used and managed. Engaging users to achieve these objectives will be key.

Consider how you can:

1. Reduce energy demand
2. Avoid waste
3. Improve building controls
4. Use lower carbon energy supplies

Carrying out works

Once you’ve made as many “non-invasive” improvements as you can, next consider what alterations or improvements to the building are needed. Often these may involve upgrading insulation and tailoring HVAC systems. Any retrofit or restoration should be sustainably carried out. A whole life carbon assessment is a must – what materials will you use for the works (consider locally sourced materials and traditional craftsmanship), how will these add to the embodied carbon of the building and what is their impact on the building’s lifecycle? Aim for green building certification.

Take a holistic approach – balancing the benefit of the decarbonisation proposals against the potential harm. There are significant risks in decarbonising badly. Not only may you fail to achieve the intended savings or reduction in impact, but critically you may detrimentally affect the building’s heritage value and significance and even cause damage to the building’s fabric or human health if the decarbonisation is not properly carried out.

Regulatory challenges

Alterations will likely require planning permission, listed building consent and compliance with building regulations.

Planning permission

Chapter 16 of the National Planning Policy Framework (which local planning authorities (LPAs) are required to take into account in determining planning applications) deals with heritage assets. It requires a positive strategy for the conservation and enjoyment of the historic environment which takes into account:

1. The desirability of sustaining and enhancing the significance of heritage assets, putting them to viable uses consistent with their conservation
2. The wider social, cultural, economic and environmental benefits that conservation of the historic environment can bring
3. The desirability of new development making a positive contribution to local character and distinctiveness
4. Opportunities to draw on the contribution made by the historic environment to the character of a place

When applying for planning permission, the NPPF requires you to describe the significance of the heritage asset within its setting in sufficient detail (proportionate to the asset’s importance) to understand the potential impact of the proposed works. You may want to enlist appropriate expertise to help with the assessment.

The LPA must then assess the particular significance of the heritage assets impacted, taking into account principles 1-3 outlined above.

Assessing harm 

The NPFF distinguishes between substantial harm, total loss or less than substantial harm to an asset’s significance. Any harm requires clear and convincing justification and at all times, great weight will be given to conservation.

• Substantial harm to/loss of Grade II buildings/parks/gardens should be exceptional
• Substantial harm to/loss of assets of the highest significance should be wholly exceptional
• Planning consent should be refused where the proposals will lead to substantial harm to/loss of a designated heritage asset unless:
  • The harm/loss is necessary to achieve substantial public benefits that outweigh the harm/loss
  • The nature of the heritage asset prevents all reasonable uses of the site; there is no viable use of the heritage asset that will enable its conservation; conservation by grant-funding or some form of not for profit, charitable or public ownership is demonstrably not possible; and the harm or loss is outweighed by the benefit of bringing the site back into use.
• Where the proposals will lead to less than substantial harm, the harm must be weighed against the public benefits of the proposal (including securing its optimum viable use)
• For applications affecting non-designated heritage assets, a balanced judgement is required having regard to the scale of any harm/loss and the asset’s significance
• Proposals making a positive contribution to the asset or which better reveal its significance should be treated favourably

Each LPA may have its own development plan policies relevant to heritage assets which you’ll need to address too. 

Listed Building Consent

There are around 500,000 listed buildings in the UK, over 90% of which are Grade II listed, 6% are Grade II* and 2.5% are Grade I and many are owned by universities. Listed Building Consent (LBC) will be needed (in addition to planning permission) for works which affect the character of the asset as a building of special architectural or historic interest, whether positively or negatively. Liaising with the local authority Conservation Officer before applying may help save time and money, to establish if LBC is needed and what might be acceptable so plans can be adapted accordingly.  

If it's not clear whether LBC is required, you can apply for a Certificate of Lawfulness of Proposed Works. The LPA must issue a Certificate if satisfied that the works would not affect the asset’s character.

The LBC application should identify what is of special interest and how the proposed works avoid harm or, if unavoidable, how harm will be minimised. Potential harm will be weighed against public benefit. The Planning Practice Guidance (PPG) defines benefits as “anything that delivers economic, social or environmental objectives as described in the NPPF” and deliver public, not just private benefit. It identifies examples of heritage benefits, including:

• Sustaining or enhancing the special interest of a listed building and the contribution of its setting
• Removing or reducing risks to a listed building
• Securing the optimum viable use of a listed building: use which is both most useful to the owner and most supportive of its long-term conservation

The LPA will have special regard to the desirability of preserving the building, its setting and/or any features of special interest. Historic England provides useful guidance on applying for LBC. Carrying out works which affect the asset’s special interest without obtaining LBC is a criminal offence. 

Building Regulations

Building Regulations set standards for construction of buildings to achieve minimum levels of performance. Listed and heritage buildings are still required to comply. Approved Documents which accompany the Regulations do recognise the special requirements of historic buildings. For example, there's an exemption from the energy efficiency requirements in Part L (Conservation of fuel and power) where compliance would unacceptably alter the character or appearance of a listed building or building within a conservation area.

Legal challenges

Alongside the regulatory challenges of carrying out works to a heritage asset, there may be accompanying legal challenges arising from covenants or restrictions affecting the property. If the property is leased, the university will need to ensure that it has sufficient rights reserved in its lease not only to enter the property to carry out the works, but to subsequently collect and analyse environmental performance data to assess the success of the works carried out. Collaboration with tenants and occupiers will be fundamental here. Once works are done, the university’s estates team must work closely with the occupiers to fully explain any new buildings systems, to make sure they are operated to their maximum potential – projected savings will only materialise if the building is used and occupied as intended.  

Financing the improvement works will also need to be considered. Salix funding may be available. If external funding is sought, the terms of the loan may include KPIs that have to be met in terms of environmental performance. This again highlights the need to be able to effectively measure and analyse data from the building. Again, early discussions with the funder may be helpful, to ensure all stakeholders are on board with the works proposals.

Construction contracts and appointments will also need to include appropriate provisions to ensure the university’s  decarbonisation objectives are clear and the works are carried out to achieve these.

In short, there are several legal, regulatory and practical considerations when decarbonising heritage property but taking a holistic approach from the outset will help smooth the path to lowering emissions. 

Our content explained