Energy efficiency has become increasingly important in historic buildings
Energy efficiency has become increasingly important in historic buildings © Historic England
Energy efficiency has become increasingly important in historic buildings © Historic England

Retrofit and Energy Efficiency in Historic Buildings

These pages and our free to download publications include technical advice and guidance on the adaptation of historic buildings for climate change resilience, including energy efficiency, retrofit, and the journey towards a low carbon future.  

The advice and guidance are intended for professionals, contractors, building managers and maintenance teams, suppliers or officials who wish to support existing knowledge or expand their understanding to enable informed decision-making and technical advice for customers. Building owners and occupants may also find it helpful.

Improving energy efficiency

We use the term retrofit to refer to the improvement of an existing building to ensure it is responsive, resilient, and well adapted for our changing climate. 

Successful retrofit projects take into account the context, construction, condition, significance, occupants, and use of the building. The resultant holistic and balanced solutions save energy, maintain a comfortable and healthy indoor environment, while sustaining heritage significance. Certain retrofit measures, specifically those for modern construction, are not appropriate for historic and traditional buildings. 

Fundamental principles of energy efficiency in historic buildings

A thorough understanding of a building and its context will ensure improvements are suitable, proportionate, timely, well-integrated, effective, and manage the risks of unintended consequences. A whole building approach can identify balanced solutions that save energy, sustain heritage significance, and maintain a comfortable and healthy indoor environment. 

Traditionally constructed Buildings can be up to 50% more energy efficient than current EPC methodologies predict. Gathering robust objective data, including Energy Assessment or Building Performance Evaluation as far as is practicable, is fundamental to identifying the accurate energy performance baseline of a building. Early investment in surveys and data gathering can save on capital costs of proposals, which are often more suitable, simple, and cost-effective as a result.

Building repair and maintenance, reducing infiltration losses, improving efficiency of building services and ensuring their effective use, are lowest cost and lowest risk place to begin increasing energy efficiency in historic buildings. Many actions, often considered outside the scope of ‘retrofit’ projects, can be taken ahead of fabric improvements to provide significant energy and carbon-reduction potential (Wise, 2022). Maintenance, periodic renewal, and conservation-focused refurbishment have the potential to save between 30 and 50% of carbon emissions, and along with this, up to 40% savings in energy consumption (Ritson, 2020).  

Many adaptation measures for resilience are also effective energy efficiency measures. Understanding climate change hazards, and opportunities to manage the risk of harmful impacts, will support effective decision making when altering buildings. Improvements designed and planned with climate change resilience in mind minimise risk of unintended consequences.  

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Where thermal upgrades are feasible and appropriate (considering need, material compatibility, moisture risk, climate hazards), primary focus should be ensuring thermal continuity to avoid creation of thermal bridges. Targeting upgrades to instances that provide the maximum relative thermal improvement, while not undermining resilience, will be most effective and cost efficient. For example, upgrading thin brick structures will be more beneficial in relative terms than upgrading mass solid walls. Mass solid wall buildings also have a great propensity to buffer fluctuations and extremes in temperature, humidity, and weather events.  

Be mindful of embodied carbon, resource intensity and environmental impact of mitigation or adaptation choices, alongside potential reductions in operational carbon. Making energy efficiency improvements to existing buildings has been shown to be at least 4% better (and in some cases up to 60%) than if you were to demolish and replace when considering carbon within a whole lifecycle analysis. Considering lifecycle analysis also allows you to consider the environmental sustainability of your choices more widely, which can support any climate resilience measures you take, as well as the whole building approach.  

Energy Sufficiency is an essential part of a sustainable energy future. The principle prioritises a shift away from efficiency alone and towards using less energy in absolute terms to deliver well-being within planetary boundaries.

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Whole building process for historic buildings

There are many ways to improve energy efficiency and climate resilience of existing buildings but need and opportunities can vary widely depending on context.  

It is essential that proposals are considered in a holistic manner to guarantee existing buildings are resilient, well adapted and continue to provide healthy environments in our changing climate.  

Measures used in combination can have a powerful multiplier effect, so understanding how measures interact and perform as part of an overall system is crucial.  

The whole building approach is a systematic process for devising and implementing suitable, coordinated, balanced and well-integrated solutions which: 

  • Consider a building in its specific context  
  • Are proportionate, effective, and cost efficient 
  • Avoid harm to the historic and aesthetic interest of the building 
  • Minimise the risk of maladaptation or unintended consequences  
  • Ensure a healthy and comfortable internal environment  
  • Increase climate resilience and minimise environmental impact  

This process involves linking assessment, design, construction, use (training and handover), quality assurance, and feedback. It allows solutions of all kinds to be reviewed and assessed carefully at every stage of the process, conflicting aims to be reconciled, or compromises to be agreed upon. The key stages are:

  • Stage 1: Whole Building Assessment  
  • Stage 2: Whole Building Planning  
  • Stage 3: Detailed Design and Specification  
  • Stage 4: Installation  
  • Stage 5: Use, review, and maintenance  

Taking a whole building approach does not mean that works must be undertaken as a single event. Any required works can be phased to suit budget constraints, tie in with the replacement of services or building elements, or with planned building works. Savings from early energy efficiency measures can fund later improvements. Properly considered, coordinated, and phased projects can prevent unnecessary works being undertaken at early stages.  

Building owners, managers, and occupants play a crucial role in reducing energy use and should be fully engaged throughout the planning process. Decisions and actions taken at every stage of the process affect the quality and success of the outcome. 

Often, the range of knowledge and skills required will not be available from a single source. Individual specialists might be needed to perform the tasks of assessment, appraisal, design, installation and evaluation. This is especially true with larger, more complicated projects. See our page on finding the right professional help.

Upgrading thermal elements

Our guidance offers advice on the principles, risks, materials, and methods for improving energy efficiency by: 

Energy efficiency research

Our guidance is informed by research on understanding the energy performance of historic buildings and the effects of energy efficiency measures. The Heritage Counts report highlights the importance of our built historic environment and explains why it has a vital role to play in the journey towards a low carbon future.  

Some improvements may not deliver the savings predicted and can harm the building, as well as the health and well-being of its occupants. 

Our current 5 main areas of investigation are:

  • Thermal performance of traditional buildings 
  • Moisture accumulation in building fabric due to energy efficiency measures 
  • Modelling of hygrothermal behaviour of building fabric as a risk assessment tool 
  • Whole building approach to energy saving in historic buildings 
  • The SPAB Building Performance Survey 

Further information can be found on our research pages. 

Planning advice

Our Advice Note 14: Energy Efficiency and Traditional Homes provides guidance on the policy and regulatory context for making energy efficiency improvements, and assessing harm to the heritage significance of listed and non-designated buildings. 

Our Advice Note 16: Listed Building Consent gives both general advice for owners of listed buildings about listed building consent as an application process and on how to judge whether proposals need consent, how to achieve certainty on the need for consent and how to make informed applications. It also gives advice on works which may or may not need listed building consent, depending on how the works are proposed to be carried out.

Learn more: Historic England webinars

View the webinar on Retrofit Fundamentals.

This webinar explains the fundamentals of historic building retrofit and clarifies where to start when considering improving the energy efficiency of traditional buildings.

View the webinar on Climate change adaptation: Assessing future summertime overheating risk in historic buildings.

This webinar discusses key findings from an on-going research study to assess overheating within historic buildings. Using the Historic England estate as a living lab, the Cambridge, Newcastle, Swindon and York offices have been analysed with dynamic thermal modelling software.

View the webinar on Achieving an EPC rating and the implications for traditional buildings.

Following the government consultation on ratcheting Energy Performance Certificate targets for non-domestic buildings, Historic England commissioned feasibility studies on two of their own Grade II listed office buildings to assess what impact this would have on historic buildings and the limitations of the EPC asset rating therein.

View the webinar on Climate change adaptation: Whole house approach to retrofit.

Old buildings are very variable, and there is no 'one-size-fits-all' solution to retrofit for traditional buildings. The 'whole house' approach considers the interrelationship between the occupants, the building fabric and the services of individual buildings. It then aims to find bespoke balanced solutions that save energy, sustain heritage significance and maintain a healthy indoor environment whilst managing the risks of unintended consequences.

Learn more: Podcasts

Listen to AJ Climate Champions podcast: Historic England’s Morwenna Slade on the limitations of ‘fabric first’ (November 2022).

Our Head of Historic Building Climate Change Adaptation explains why insulation is the area of highest risk when working with heritage buildings.

Listen to RICS: A Future-Thinking Outlook on Residential Retrofit with Historic England’s Hannah Reynolds (August 2023).

As a part of the Expert Working Group for the RICS Residential Retrofit Standard, Hannah Reynolds discusses how to shift misconceptions about retrofitting traditional buildings and the release of a brand-new consultation for the RICS Residential Retrofit Standard.

Learn more: Sustainable Traditional Buildings Alliance (STBA)

Historic England is one of the supporting organisations that make up the STBA, a forum for sustaining and improving traditionally constructed buildings.

The STBA's website offers guidance on:

Planning Responsible Retrofit of Traditional Buildings. Part funded by Historic England, this guidance looks at the complexity and uncertainty in the way older buildings, new technologies, nature, and people perform and interact. By taking a whole building approach, risks and liabilities can be reduced.

The Responsible Retrofit Guidance Wheel. Funded by the Department of Energy and Climate Change (now part of the Department for Business, Energy & Industrial Strategy), the guidance wheel is an online interactive tool. It lets you look at how over 50 measures interact and the risks to consider before installing.

STBA Whole House Approach. This guidance outlines the whole building approach to retrofit which takes a holistic approach based on the context of the building taking account uncertainty, the complexity of interactions and conflicting values.

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