Any existing issue, relating to the efficiency and performance of a building should be addressed before further retrofitting options are considered. The performance of the building needs to be fully understood. When upgrading elements to achieve U-values, in-situ testing is recommended to understand the building performance before any works. Unfortunately, there are assumptions about the poor energy performance of older buildings, which are included within engery modelling systems and data. Historic England’s research has suggested that performance of solid brick walls was a third better than the performance predicted by energy-performance models. This could impact the type of insulation being considered, as well as the amount and the overall cost of the works to achieve the U-value target.

Each element that could be retrofitted will be considered below. Whilst these elements are being considered in isolation, every change that is made will have an impact to a building’s performance. As such, multiple energy efficiency measures will have interrelating considerations. This is considered as part of PAS2035. The STBA Guidance Wheel also provides further information on this and should be referred to before making any changes.

Each element has been identified as either a low, medium or high-risk intervention. Below identifies the considerations for the different levels of heritage risk.

Low risk:

• Majority of or all historic fabric retained
• No impact to the significance of the building
• Is considered to be compatible with the existing building fabric and heritage asset’s significance

Medium risk:

• Subject to detail if it could result in unintended consequences, such as moisture build up ventilation
• Limited to small impact to the significance of the building
• Could be compatible with the existing building fabric

High risk:

• Items that are subject to the design and detail
• Little historic fabric retained/is at high risk of being lost in the future
• High or detrimental impact to the significance of the building
• Is considered not to be compatible with the existing building fabric

Energy efficiency and retrofitting traditional buildings: Key Documents and Links

Historic England Energy Efficiency Series

Historic Environment Scotland, Guide to Energy Retrofit

Historic Environment Scotland, How to improve energy efficiency

STBA Planning responsible retrofit of traditional buildings

STBA Knowledge Centre and Guidance Wheel

Grosvenor and Westminster City Council The Grosvenor Estate toolkit on sustainable refurbishment for leaseholders

LETI Climate Emergency Retrofit Guide, 2021

PAS 2035/2030:2019+A1:2022 Retrofitting dwellings for improved energy efficiency. Specification and guidance

 

Recommended Books

Historic England, Practical Building Conservation: Building Environment, Oxford: Routledge, 2014

The SPAB, Old House Eco Handbook: A Practical Guide to Retrofitting for Energy Efficiency and Sustainability, London: White Lion Publishing, 2019

Sofie Pelsmakers, The Environmental Design Pocketbook, 2nd ed., London: RIBA Publishing, 2015.

Christopher Day, The Eco-Home Design Guide: Principles and Practice for New-Build and Retrofit, Cambridge: Green Books, 2016

Prince's Regeneration Trust, The Green Guide for Historic Buildings: How to Improve the Environmental Performance of Listed and Historic Buildings, Norwich: TSO, 2010