As Government, construction professionals and individuals work enthusiastically to progress to Net Zero, energy-efficiency has increasing weight in the determination of Planning Approvals.
Research undertaken by Historic England and others has provided a better understanding of the value and opportunities offered by historic building stock in supporting sustainable development. Heritage buildings can provide a useful resource within regeneration projects, offering embedded carbon values or a significant reduction in materials and energy waste resulting from demolition works. Retaining and re-purposing these buildings is more energy efficient over the long term than demolishing and building anew, and these buildings also offer economic and social cohesion benefits.
To achieve the long-term sustainability of historic buildings, we must know how to adapt and maintain these properties, so they function with the higher levels of energy efficiency and savings required to meet modern low carbon targets. This blog looks at this need.
The good news is that our historic buildings are more adaptable than often credited.
The UK’s historic building stock varies widely in construction materials including brick, masonry, timber-frame, cob, and thatch as examples of types. Added to this, historic buildings may have internal characteristics and features that need preserving. They may be in conservation areas where overall appearance and ‘historic setting’ becomes important, or they may have ‘cultural heritage’ significance that may not be immediately apparent. So, the crucial starting point to any energy efficiency works undertaken to historic buildings is to understand their heritage significance which will enable a better understanding of the building’s adaptability, future treatments, and potential.
Striking the right balance between achieving energy efficiency benefits and protecting heritage structures is not always straightforward. Poorly executed plans to improve energy performance can undermine heritage values. It can compromise human health and create conditions leading to the damage of the building’s fabric, reducing its lifespan. It can fail to achieve cost-effective energy efficiency benefits or reverse damaging environmental impacts.
Energy-efficiency measures require an holistic approach.
Historic England (2020) suggests however, that getting the balance right is completely achievable with a sound understanding of the ‘whole’ building. That means, its heritage value, its historic purpose and future-use plans, its construction and where it is located, including its exposure to the Elements. This comprehensive approach will ensure that ‘energy-efficiency measures are suitable, robust, well integrated, properly coordinated and sustainable.’
Historic England has produced a series of documents that sets out guidance for improving energy efficiency in traditional homes HE, 2020. Energy Efficiency and Traditional Homes (built pre-1919).
It is useful to note that Listed Buildings and buildings in conservation areas can in certain circumstances be exempt from the need to comply with energy efficiency requirements under Building Regulations: Conservation of Fuel and Power: Dwellings (Part L) where compliance would unacceptably alter their character or appearance. ‘Special considerations can also apply to buildings that are locally listed, of traditional construction, in national parks or other designated historic areas. The legislative detail can be confusing to work through, so seeking the advice of your local Planning Authority Conservation Officer and a professional Heritage Consultancy like AB Heritage is a good first step to guide you through the process and identify opportunities and constraints specific to your project.
Proposals for energy-saving measures are more likely to achieve Planning Approval if they demonstrate knowledge and understanding of the building’s significance.
Your Heritage Consultant and/or Local Conservation Officer will be able to offer guidance on your building’s construction and important heritage features. Planning approvals will look to ensure that any works undertaken employ only sympathetic materials deemed as appropriate to the building fabric and usually the same as the original. Where this is not possible, materials should demonstrate compatible properties and be visually similar. Well-designed works will respect a buildings heritage, be technically achievable and not likely to prejudice future works.
In addition to this your Heritage Consultant will also undertake an advocacy and negotiation role with relevant stakeholders on your behalf and ensure that any proposed works align with national and local policies for heritage protection. They will look for opportunities to better reveal or enhance heritage.
So how can historic buildings be adapted to become more energy efficient and reduce carbon emissions?
All projects will be individual in their opportunities and challenges to achieve efficient energy performance.
In all cases, the importance of appropriate repairs and routine maintenance as key energy-saving measures cannot be overstated for heritage buildings. Not just because they are good for the health of the building but to create the best conditions to support energy performance improvements.
The following are examples where ‘quick-win’ energy-efficiency gains can be achieved.
External works such as removal of vegetation around walls and skirts will help to reduce damp and support a stable internal environment. Consideration of land drainage pipe works can remove water flows away from under buildings to good effect.
The introduction of solar panels (photovoltaic) can be an effective way of generating energy without introducing overly intrusive changes.
There are various means of installing solar panels either at ground level, on the roof (behind parapets) or the use of solar glass (incorporated into conservatories/orangeries). Listed Building Consent may be required in a Conservation Area.
Ground source heat pumps are an efficient way of supporting the generation of hot water using the higher ambient below-ground temperatures to boost water temperatures that heat your building. There are some heritage buildings that cannot achieve Government performance targets using ground source heat pumps. Heating specialists would be able to provide performance ratings. Regarding heritage, archaeology may be a consideration when contemplating ground source heat pumps.
Internal adaption / Retrofitting.
The replacement of windows, where original wooden elements and rare original glass are present is unlikely to achieve approval over repair works, even where these may need to be extensive.
Draught proofing windows and doors can reduce air leakage from windows by between 33% and 50%. The Installation of secondary glazing, heavy curtains and well-fitting shutters may reduce heat losses through a window by around 40%. Repair to ill-fitting doors, loft spaces and wall insulation are all methods that may be appropriate options for certain building types.
The removal or re-positioning of later partition walls may allow for improvements in energy saving and restore the natural transmission of moisture and ventilation through the historic fabric of the building where this is fundamental to its design and operation as an effective space.
For works where some form of heat pump is being considered, Historic England provides guidance covering the options for installing such systems into historic buildings.
The outcome to all energy improvement works should also maximise the life of the building and not harm its heritage significance.
AB Heritage has been helping clients to manage historic environment planning requirements across the UK for over a decade. Professional consultants operate from offices in Newcastle, Leeds, London, and Exeter and from remote locations. AB Heritage is a registered archaeology organisation with The Chartered Institute for Archaeologists. www.abheritage.co.uk