Retrofit ‘daemons’ in the process of low-carbon housing stock renovation

The ‘performance gap’ between design and actual energy use is well recognised. Much of the debate on the performance gap focuses on the use and accuracy of building energy models or on the ‘misbehaviour’ of users and maloperation of measures. This paper focuses instead on the design and construction phases of retrofit projects. Pioneering case studies in deep low-carbon refurbishment in the UK show a lack of quality assurance and poor integration of the intermediate stages between design and implementation within retrofit process. In retrofitting existing buildings there is an unseen presence of ‘good’ and ‘evil’ daemons that are ‘hidden’ in different retrofit work stages. The intermediate construction stages from design to delivery tend to involve the majority of unforeseen complexities that are difficult to know until work is under way. The consequence of this is not only an uncertainty in actual energy performance that challenges the ambitious carbon emissions reduction targets, but also an unwillingness to invest in low-carbon technologies due to concerns about what will actually be achieved. A more sophisticated understanding of the different types of risks within the retrofit process, from technical or economic risks to commissioning and handover related ones, is required. Using established professional work plan frameworks, this paper first defines a Plan of Work as a continuous cycle of different retrofit workstages and roles, augmenting and assisting current professional scopes of service, not replacing them. The notion of ‘risks’ is used as a lens for managing and reducing unintended consequences and the performance gap. Drawing upon the evidence from academic and grey literature review, this paper then defines the types of risk(s) encountered within the different retrofit workstages by exploring evidence-based problems, concerns and ‘daemons’ that emerge as major contributors preventing the full potential of low-carbon refurbishments from being achieved.