Rethinking retrofit of residential heritage buildings

Abstract

What are the opportunities and challenges for upscaling the energy retrofit of heritage buildings? Heritage buildings comprise approximately 20% of the UK building stock and are challenging to retrofit sensitively because of their heritage values and traditional construction. These buildings may therefore be unconducive to standard retrofitting approaches. Twelve case studies in the UK are examined. Three key findings are presented together with their implications for upscaling retrofit. First, heritage residents are found to engage in positive energy behaviours, which differ from standard assumptions and have a significant impact on energy demand. Second, standard energy models are shown to considerably overestimate the energy use within heritage buildings, failing to accurately portray both traditional construction and residents' behaviours. Third, residents consider many common retrofits, such as replacement windows and wall insulation, to be unacceptable to their heritage values. A number of more acceptable and less invasive 'soft retrofits' were modelled and shown to have significant potential for reducing energy and carbon. Therefore, a more holistic approach to heritage building retrofitting needs to be taken, treating the complex interrelationship of buildings and their users as a system, and expanding notions of retrofitting to include soft retrofits and user behaviour. POLICY RELEVANCEThis research identified the importance of appropriately retrofitting heritage buildings, which include around 20% of the UK building stock. Standard solutions such as wall insulation and window replacement are unlikely to be enacted by most heritage residents because they are not acceptable to their heritage values, suggesting the need to prioritise other measures. Standard energy models such as Reduced data Standard Assessment Procedure (RdSAP) were found to be inaccurate for heritage buildings, overestimating energy use by both buildings and occupants, and should not be used to inform retrofit decisions for these buildings. Notions of retrofit should be expanded beyond fabric FREYA WISE ALICE MONCASTER

Residents’ comfort perceptions in domestic heritage buildings

“…The case studies were chosen from amongst the survey respondents to cover a range of building types, ages, locations, and household compositions. More details on the case studies can be found in [20]. Both the survey and case studies received ethical approval.…”

“…In contrast to the survey respondents, almost all case study participants were content with current thermal conditions in their homes, apart from CS2 and CS10 who were both dissatisfied with their current heating systems and were actively looking to improve them. Many of the participants (CS1, CS5, CS6, CS11, CS12, CS14) who were thermally comfortable nevertheless recognised that their homes have lower than average temperatures and that visitors sometimes found conditions cold [20]. They identified that they had acclimatised to conditions in their homes, and moreover, that they engaged in practices such as wearing additional layers which meant that they found their buildings comfortable.…”