Deep retrofit approaches: managing risks to minimise the energy performance gap

Energy use in buildings remains a significant part of overall energy demand. Deep renovation projects, delivered at scale, remain a challenging task to achieve a lower carbon building stock.The complexity of building renovation beyond standards and building specifications is related to inherent characteristics of buildings which require distinct project management techniques. While there are now more projects focusing on achieving operational performance, there is still very little research on the management of the renovation and retrofit process itself. Recognising that each project working on an existing building is unique in type, timing, energy goals and the roles/characteristics of people involved, the aim of this paper is to add to the current debate of how intervention approaches (one-off or over-time, whole-house, fabric-first room-by-room, measure-by-measure) are promoted by different policies, and with what impact. The paper discusses the complexity of a deep renovation project in terms of planning and management and the ways current policies can lead to unintended consequences in the short and long term, as well in lock-in effects that contribute to energy performance, and to the gap between designed and actual energy performance. Using a typology of risks, the issues associated with renovation processes and technologies were explored in a sample of cases studies from deep retrofits across the EU. The evidence from these shows that despite holistic planning for renovation, interventions tend to be carried out in phases. These contrasting time dimensions and the different retrofit approaches are discussed with risk profiles for each retrofit project, suggesting how risks emerge throughout a project. A series of risk mitigation strategies are suggested which, taken in combination to suit a specific project’s risk profile, may serve to reduce and potentially eliminate the building renovation energy performance gap

Low-carbon refurbishments: how passive or active are technologies, users and their interaction?

Current regulatory and other policy trends in housing refurbishments relating to low-carbon performance standards involve complex technologies and systems as well as innovative solutions to achieve the UK’s demanding targets. Performance indicators of domestic refurbishments in general tend to rely heavily upon assumptions of ideal performance of materials, combined systems installed to high standards under specific conditions, and ideal occupant behaviour in operating and interacting with them. Previous studies exploring the influence of socio-technical factors on the UK’s domestic energy use highlight that one of the main reasons for limited success in achieving energy targets is the lack of understanding of how people interact with domestic technology. Using a sample of nine low-carbon whole house retrofits in the UK this paper explores occupants' interaction with heating and ventilation measures as designed, installed and operated. The paper discusses the central phenomenon of interaction within three key areas: technical aspects (building fabric and systems), occupant (user) and interaction (energy use and operation). Using an interdisciplinary methodological approach qualitative and quantitative empirical data were explored together, cross-checking occupants’ ‘doings’ and ‘sayings’. The paper presents preliminary evidence-based findings showing the extent to which active measures as designed and installed have fostered direct interaction involving active users, as well as the tendency of passive low-carbon measures designed and installed for passive users to involve indirect interactions with active users in practice. The analysis of findings identifies significant factors in combined active and passive systems that are relevant to everyday practices of heat and ventilation interaction.</p

Understanding occupants' interaction with the technical change in low-carbon retrofits: a methodological and conceptual framework

Little is known about the interrelations between behavioural aspects and physical dependences in energy use from empirical data. Empirical research on occupants’ ‘interaction’ with the technical changes in low-carbon retrofitted homes demands holistic socio-technical approaches. The aim of this paper is to present the methodological and conceptual framework of ongoing doctoral research focussed on the interaction between retrofitting interventions and occupants’ behaviour and the extent to which this affects the energy use of the UK’s refurbished housing stock. The paper discusses methods and occupant feedback techniques for low-carbon refurbishments. It presents the theoretical foundation of a methodological design developed to investigate, observe and analyse the ‘phenomena’ of individual household energy use based on one year’s monitoring data. The presented methodology is built up to estimate the ‘area of interaction’ of these variables on empirical findings, by defining the nature (direct/indirect, passive/active) and extent (low/zero, medium, maximum) of occupants’ interaction with technical refurbishment interventions. The paper concludes with an overview of a method structured to examine the importance of user’s ‘interaction’, by disaggregating the association of socio-technical variables and evaluating the behavioural dynamics in energy use

Deep low-carbon refurbishment challenge: what hasn’t worked as designed?

Whilst building regulations standards become more stringent to meet UK Government ambitious reduction targets by 2050, low-carbon solutions in building stock refurbishment do not always perform as design intended. Considering this, and given that there is still little evidence on deep refurbishments that implement low-carbon ‘whole house’ approaches in the UK, this paper presents evidence on the implementation, installation and use, using a sample of 26 deep retrofitted social houses. The paper explores what has (or has not) been implemented as intended /designed discussing the failures and successes emerged under the lens of effectiveness in delivery, performance, occupants satisfaction and control interaction with the low-carbon building system. Using interdisciplinary methodological approach technical and non-technical factors are examined through a detailed analysis of the quantitative and qualitative empirical data. The overall performance in-use is discussed in relation to the initial refurbishment delivery goals. The findings reveal issues correlated to knowledge, skills, communication and quality of installation of the low-carbon interventions and how these affect occupants’ interaction and control behaviour. By recognizing the importance to provide higher standards in installation of the new measures improving quality controls in the implementation, the research outlines key messages and recommendations to different sectors (policymakers, researchers, implementers, supply chain and users) that are involved in social housing refurbishment programmes

The time dimension in deep renovation: evidence and analysis from across the EU

Deep renovation of buildings is acknowledged both as a national and EU priority, and as being very difficult to achieve at sufficient scale and speed. A novel way to understand this complexity is to look at how renovation relates to time and timing in the physical, commercial and social systems in which it is embedded. Deep renovation fits into a complex set of timings: time taken to renovate, the lifetime of individual measures, the payback time of investments, the amount of time a building is owned or rented, the life / business stage of occupiers, moments of opportunity. The aim of this research is to better analyse, characterise and contextualise the time dimensions of deep retrofit, from policy, market, building and user perspectives, and thus to suggest how deep retrofit can be accelerated. The research begins with case studies which take different approaches to time. First are those which aim to speed up retrofit. This can be by technical innovations which focus on fast production and fitting of energy saving technologies, or though subsidised funding mechanisms, or both. Examples include KfW loans and Energiesprong. The alternative approach is to encourage deep staged retrofit over a longer time scale, e.g. via individual building renovation roadmaps. Involvement in the retrofit process is elongated rather than compressed in time. In parallel we gather empirical evidence from EU-funded H2020 projects, recent UK renovation research, member states’ building renovation policies, and communication materials from EU-level think tanks and NGOs. Analysing this data, together with the case studies, we look at how deep renovation as a whole is envisaged playing out over time, and the time characteristics of proposed solutions and the extent to which they respond to faster and further policy targets.The paper concludes with suggestions on how EU and national policy could be re-framed to better support deep renovation.</p

What buildings policy might look like if we took climate change seriously

In 2018, the Intergovernmental Panel on Climate Change released its report on the impacts of global warming of 1.5°C. It called for "rapid, far-reaching and unprecedented changes in all aspects of society" to reduce the risks of increasing climate change. Energy use in buildings is one of the key contributors to greenhouse gas emissions in the UK and EU. Detailed policies to support high standards in new build and acceleration of ambitious retrofit are a necessary part of any serious response to climate change. This paper begins with a description of key UK policies on energy use in the buildings, and future UK government plans as expressed in the Clean Growth Strategy. It analyses the direction of travel, and looks at the rate of change compared with what will be required to rapidly reduce carbon emissions from the sector. Current buildings policies are insufficient to meet the challenge of climate change. Both positive and negative examples of changes in policy are presented. A new conceptualization of the contribution of energy demand to delivering net zero goals, developed by CREDS, is introduced. In addition, key characteristics of the buildings sector and its energy use are put forward. Bringing together the role of energy demand, these characteristics of buildings, and the broader literature on buildings and energy policy, we have set out an exploratory set of guidelines for developing policy to reduce carbon emissions from buildings further, faster and more flexibly. These are classified into the guiding principle, approaches to policy creation, expanding the boundaries of policies and focus on quality. These should form the basis for further discussion. If policy were designed as if we took climate change seriously, according to the guidelines developed, what would this mean for buildings? Fundamentally it would require a momentous change in the culture of construction, so that what is valued moves beyond design, aesthetics and functionality, to include low carbon and highly efficient performance. New targets and approaches to delivering them are required – and this paper contributes to thinking about both

Residential retrofit in the climate emergency: The role of metrics

This paper examines whether current residential retrofit metrics are fit for purpose and if they can help deliver swift and significant cuts in carbon emissions. Information is presented on metrics used for a variety of UK and European Union building and building retrofit standards and evaluation and assessment tools. An analytical approach is developed that offers a simplified set of four key aspects of metrics: scope, headline measurement, normalisation factor and timescale. This helps to unpack the complexity of metric design. However, choice of metrics is not simply a technocratic issue, because their design is not value free. Two examples where metrics form the basis for policy-making for retrofit and energy use in buildings are described: UK Energy Performance Certificates and the Energiesprong approach to deep retrofit. Use of multiple metrics improves their fitness for purpose and is already established practice in some standards and policy. Metrics in common use omit many aspects of energy use in buildings. New metrics are required that can take account of the whole life of a building, the time profile of retrofit, or the ability of the building to be flexible as to when energy is used

Exploring the practices and roles of UK construction manufacturers and merchants in relation to housing energy retrofit

Buildings contribute significantly to CO2 emissions but also have large technical potential for improvement, making them a key sector for climate and energy policy. The UK’s energy efficiency policy for existing housing has focused historically on relatively cheap and minimally disruptive individual measures, whereas climate targets indicate the need for more holistic, costly and disruptive treatments. The construction industry is a vital potential enabler of this policy goal, but the industry has not yet been successfully enrolled in what amounts to a profound change to industry practices. A focus on supply chain actors is justified by previous research, which identified that installers and builders are influential over project design, specification and delivery, but that the installers are in turn constrained by their suppliers in what is more properly considered a ‘value network’. Firms operate as ‘middle actors’ between bottom-up consumer demand and top-down policy. Eleven interviews were carried out with a purposive sample of merchants and manufacturers in the UK construction value network, deliberately skewed to include a number of innovators and niche ‘green’ firms alongside larger-scale manufactures and wholesalers. Qualitative analysis highlighted six key themes: industry practices; skills and knowledge; roles and responsibilities; innovation; engagement with installers; and policy. Six different roles were identified in the construction value network, combining aspects of manufacture, distribution, on-site construction and end-of-life product disposal. The complexity of this value network needs to be understood, and the sector engaged with, if buildings policy is to achieve its climate targets

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 users' ‘misbehaviour’ and measures' maloperation. 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 workstages. 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.</p