Retrofitting owner-occupied housing: remember the people

Energy use in buildings accounts for almost 40% of all CO₂ emissions in the European Union and other developed countries. The building sector, and especially the housing sector, is often identified as providing the largest potential for CO₂ reduction (European Commission, 2006). Although it may be questioned whether the potential is really that big, and whether it is reasonable to place the major burden for CO₂ reductions on the building sector, there is no doubt that reduction of CO₂ emissions from buildings is of major importance. In discussions on low energy architecture, the focus is often on new buildings and their potential for reducing or eliminating energy consumption, particularly for space heating and cooling purposes. This is evident in zero-emission buildings and passive houses. However, the largest potential for energy reductions in most developed countries is within the existing buildings. The longevity of buildings and the building stock (typically 50–100 years) means that for a very long time ahead the majority of the building stock will be constituted by buildings from before the current era of low energy regulation (Power, 2008).

Both from an organizational and a technical perspective, the energy retrofit of existing buildings (hereafter called retrofit) varies extensively with different types of buildings, and the composition of types of buildings varies between countries. Consequently, the potentials for energy saving also vary between countries according to what types of buildings are most prevalent (Tuominen, Klobut, Tolman, Adjei, & de Best-Waldhober, 2012). In some countries, the largest potential for energy savings might be found in the retrofitting of existing blocks of flats. In other countries, the largest potential will be found in the retrofitting of existing owner-occupied homes (terraced, semi-detached, detached). The focus in this special issue is on owner-occupied homes, as this is a highly understudied subject with a large potential interest from both policy and practitioner perspectives.

What is significant about owner-occupied homes is that those initiating the retrofitting and those living in the house before, during and after the retrofitting are the same people. In most cases, these people do not have specific technical knowledge or an interest in retrofitting. Many policy approaches to encourage retrofitting tend either to ignore this or to treat it as a question of an information deficit to be solved. The papers in this special issue question these assumptions. Instead, an alternative approach is provided. The questions are reframed to consider:

• how retrofitting can be understood in relation to the many other practices that people perform in their everyday life in their homes

• what qualities people want their home to have

• what competing desires the retrofitting has to be negotiated against

The understanding that houses are owned, occupied and retrofitted by (the same) people implies a need to focus on the human dimensions of the retrofitting process. As will be demonstrated, the human dimension has many quite different approaches. The common contribution to policy and practice is about the need to reframe the understanding of retrofit within policy and practice from solely a technical/financial perspective to include social understandings.

Performance gaps

It is widely acknowledged that a major gap exists between the technical calculations and the actual energy consumed by the same homes when occupied by real people. This has been identified and labelled as the so-called rebound and prebound effect (Sunikka-Blank & Galvin, 2012). In general, technical calculations overestimate the energy consumption in old energy-inefficient buildings. Calculations also overestimate the energy savings in retrofitted (or new) energy-efficient buildings. Inhabitants adjust their habits to the efficiency or standard of the building in which they are living, e.g. they keep lower temperatures in inefficient houses and higher temperatures in efficient ones. Actual energy savings are thus never as great as predicted by the technical calculations. Maybe actions other than retrofitting are a better solution. This insight has major consequences for different aspects of retrofitting existing buildings. Two articles address these consequences.

First is Galvin who examines ‘Why Germans homeowners are reluctant to retrofit’. One of the answers to this problem is exactly that the economic savings in reality are never as large as the official estimates (due to the failure to account for prebound and rebound effects). Furthermore, the official assumptions and calculations about rising fuel prices, the cost of retrofitting, as well as what discount rates to use are biased in a way that makes retrofitting look more economically attractive than it most often is. The answer to the question why Germans do not retrofit is that most house owners discern the weaknesses within these official calculations. More importantly, Galvin reveals some larger energy policy implications. First is the question whether it is reasonable to assume that the building sector should provide the major CO₂ reductions (compared to other sectors), particularly if the techno-economic calculations behind this recommendation do not hold. Second is the question whether all retrofits need to be deep. If the economic calculations suggest that the final CO₂ savings are much more expensive than the first set of CO₂-reduction measures, then in some cases it might be more realistic to allow and promote more retrofits which are incremental. Finally, if deep retrofits are to be promoted, this should be based on other arguments than the economic savings. There is currently too much dependence on the argument of economic payback, which is not realistic in many cases. Other arguments and motivations exist, which can be incorporated into policy – as shown in other papers in this issue.

The second paper to examine the consequences from the gap between hypothecated calculations and real life use is ‘Better home energy audit modelling: incorporating inhabitant behaviours’ by Ingle, Moezzi, Lutzenhiser and Diamond. Again, this work is based on the distance between the theoretical calculation of energy consumption and actual consumption. Their research reveals that when inhabitants provide additional information about their own house and the way they live in the house, then the calculated energy use is more accurate. Based on these calculations, which include both the technical specifications of the house and the behavioural specification of how the house is used, it is possible to make more realistic predictions of possible savings from different technical efficiency improvements. In contrast, the calculations (based on the traditional methods) point to certain retrofitting options as economically attractive. However, this is not the case when inhabitant behaviours are also taken into account. Furthermore, the inclusion of behavioural information into calculations can also assist the inhabitants to evaluate their own behaviour and its specific impact on the energy consumption.

Learning from real-life projects

Another group of papers investigates different types of real-life experiments with getting people to retrofit. Three papers explore what can be learned from different types of projects that encourage homeowners to undertake a retrofit. Two of them consider so-called Superhomes or open-homes, where people who undertook deep retrofits then open their homes to others. The intention is to share and inspire other homeowners with information and advice on how to perform different retrofitting projects. The last of the three papers reports on a community-led project for encouraging homeowners to retrofit.

In ‘Inspiring low-energy retrofits: the influence of “open-home” events’ by Berry, Sharp, Hamilton and Killip social learning theory is used to analyze the perceptions and actions of people who have visited open homes with deep retrofits in the UK and Australia. Analysis shows that there are some good results from this approach, especially for those already interested. Results indicate that those attending show a high degree of satisfaction and perceived learning. Follow-up research indicates that many attendees do take specific actions to renovate their home afterwards. The strength of this approach is that the portrayal of retrofitting in a real-life social context can be highly persuasive.

One of the UK networks is the so-called Superhomes, where house owners have done extensive retrofitting of their home and then hold open-home events. In ‘Anatomy of low carbon retrofits: evidence from owner-occupied Superhomes’, Fawcett and Killip focus on the owners of these deep retrofit houses to distinguish what characterizes them and what motivates them. These homeowners can be seen as the first movers or early adopters. The insights from studying this special group can reveal relevant information for understanding how a broader group of house owners could opt for retrofitting. The main motivation for these people to retrofit their homes is an engagement with energy issues. It is interesting that they do not all belong to the most affluent groups of house owners. The retrofitting was financed in different ways. Common to all is that they did not take a loan to finance the retrofits. The issue of payback time for their investments was of little interest. This suggests that policy could take a broader view to explore and exploit other motivations than what is economically advantageous.

In ‘Impacts of community-led energy retrofitting of owner-occupied dwellings’, Gupta, Barnfield and Hipwood evaluate the effect of a community-led project motivating homeowners to undertake an energy-retrofit. The results are compelling: a majority of homeowners actually did save energy due to the interventions combining technical and behavioural approaches. The evaluation combined qualitative and quantitative data which in themselves are highlighted as an interesting result. The conclusions also include discussions on how community projects can be useful in developing a wider culture of energy.

These experimental projects highlight that people are different, retrofitting projects are different and thus energy policy should also be different. One paper is exemplary for describing the different types of homeowner when it comes to retrofits. In ‘A persona-based approach to domestic energy renovation’, Haines and Mitchell use the approach of developing personas. These personas are imaginary people constructed and based on qualitative interviews with real homeowners. The collection of personas does not claim to represent all possible types of homeowners. These personas visualize and communicate how differences in social background, available resources and competences together with differences in views (e.g. what constitutes a nice home) can have a huge impact on the ways and extent that homeowners retrofit their homes. These insights can help policy-makers to widen their perspective on who homeowners are and the ways they retrofit.

Policy assumptions and policy design

Policy and technological approaches often fail to articulate the underpinning ideas about how to retrofit houses. In ‘Exploring the time dimension of low carbon retrofit: owner-occupied housing’, Fawcett examines an assumption found in many policy and technological approaches that retrofitting is best if done in one process at the same time. An alternative is an incremental approach where the house is incrementally upgraded over many years while living in it. From an energy perspective, either of the two approaches cannot be said to be better than the other. The incremental over-time approach may have a better fit to the everyday life of some homeowners and therefore deserves consideration. Some new policy approaches are offered that are more relevant as these include the possibility of incremental retrofitting over a longer time span.

Another assumption underlying housing retrofit policy is that an information deficit exists for homeowners and this lack of information inhibits people from retrofitting their homes. In ‘Energy renovation practices in Danish detached homes: is the Energy Performance Certificate useful?’, Christensen, Gram-Hanssen, de Best-Waldhober and Adjei challenge this assumption with evidence from a survey about the Energy Performance Certificate (EPC) on buildings. It is found that the majority of the homeowners understand and trust the information they find in the EPC on their newly bought home. However, this information is not very helpful for retrofitting their home. What homeowners need is practical advice about retrofit options that relates to the everyday life as well as the desires and wishes of the homeowners. This might also include the costs and what energy savings would actually accrue. Thus, there is a link with the findings of Galvin's paper which indicates that homeowners need more information about actual performance, rather than merely hypothecated calculations.

Social practices and energy savings

Several of the above-mentioned papers show that retrofitting in real life often is very different from how it is conceptualized in technological and policy approaches. Some papers in this issue go even further into detail with this, exploring how practices of everyday life and practices of retrofitting a home are linked in different ways. In ‘Housing renovations and energy efficiency: insights from homeowners’ practices’, Judson and Maller conceptualize renovations as a social practice. This approach facilitates an analysis of the interactions between people and buildings. Studies of everyday or mundane practices that intersect with those of retrofitting the house reveal how energy efficiency requirements are negotiated at the household level, during both the process of retrofitting and in the daily lived experience of homeowners. These findings are in contrast with predominant approaches that rely simply on the insertion of technical interventions as a solution.

Another study posed a slightly different question: how can the planning and design of energy retrofitting include ideas about the inhabitants' everyday practices which are less energy consuming? In ‘Incorporating inhabitants’ everyday practices into domestic retrofits’, Vlasova and Gram-Hanssen use three case studies to examine different organizational approaches to the retrofitting processes to ascertain which ones have the capacity to incorporate the inhabitants' everyday practices into the planning of the retrofitting. Retrofitting processes that include a feedback loop and early dialogues between experts and householders have the potential to include this perspective. It is thus concluded that rather than viewing retrofitting as a purely technical matter that should interfere the least with the inhabitants’ life, a process where expert views and homeowners’ perspective can interchange is desirable. It is important that this includes those questions that are most important for the final energy consumption of the house (e.g. the size of the home).

Another way of applying practice theory to the study of retrofitting is to ask whether a practice exists that could be called energy retrofitting of owner-occupied housing. Many policy efforts (including the European Union's Energy Performance of Buildings Directive – EPBD) seek to encourage people to energy-retrofit their homes. What these policy policies aim to achieve is that energy retrofitting becomes normal and widespread, i.e. it becomes a practice. In ‘A practice–theory approach of homeowners’ energy retrofits in four European areas’, Bartiaux, Gram-Hanssen, Fonseca, Ozolipa and Christensen use qualitative interviews with homeowners in different parts of Europe to ascertain whether energy retrofitting is a practice. The answer to this is currently negative, although the analysis includes recommendations for how policy might better contribute to establish energy retrofitting as a practice. These recommendations includes focusing on the collective structures of what could hold a practice of energy retrofitting together rather than primarily putting attention to the individual homeowners and their decisions.

What about the supply side?

Implicit in many of these papers is the changing role and nature of the supply side. As mentioned, Vlasova and Gram-Hanssen examined three different delivery mechanisms – do it yourself (DIY), municipality-initiated and traditional building contractor – for their potential to engage with homeowners to find appropriate solutions. Following from the need to focus on both the single homeowner and the structures surrounding the retrofitting process, other relevant actors in the retrofit process can be included (e.g. the professionals and supply-side companies). This is done in ‘Low-carbon, water-efficient house renovations: an emergent niche?’, by Horne, Maller and Dalton. Based on interviews with homeowners and small construction companies involved in owner-occupied retrofits, this paper explores whether a niche might exist for construction companies focusing on water- and energy-efficiency retrofitting. The term ‘niche’ relates to discussions within theories of transition that focus on how innovation often starts in small isolated environments from where it might spread. It is concluded that this type of company does not exist as a niche, partly because energy- and water-efficient retrofitting are difficult to separate from other types of renovation. However, these companies have a significant role as mediators in the process of doing more sustainable retrofitting.

Conclusions and recommendations

The papers in this special issue stress the significance of ‘adding people’ into the policy and practical measures for the energy retrofitting of owner-occupied houses. The inclusion of new understandings underpinning the motivations and practices of inhabitants is a vital component for success – both in their engagement to undertake a retrofit and the actual outcomes of reduced energy demand. In the past, retrofitting the building stock was oversimplified into only technical and economic concerns. This omitted an active participation by the owners/inhabitants in the process as well as the lack of understanding of what retrofit options were suitable. Unsurprisingly, the results from this process have been problematic – low levels of engagement and poor outcomes that failed to match the expectations at both policy level and individual homeowners. This special issue shows that the consideration of people as active participants in the retrofit process must underpin policy and practice in order to incorporate their inhabitants' practices, behaviours, motivations and aspirations.

Drawing together the research in this special issue, three overarching recommendations are made for the inclusion of people (inhabitants) before, during and after a retrofit. Homes do not consume energy; people in homes with different types of practices and different technologies consume energy. The implication is that before retrofitting occurs the actual consumption of the specific household in the specific home needs to be considered. It is insufficient to rely upon some superficial technical calculations of the building's performance. The determination of what kind(s) of retrofitting is appropriate might change considerably based on this shift of perspective at both the household level and a national or international level. As shown in the Galvin paper, this might lead to a questioning of how realistic is the current goal for CO₂ reduction in the housing sector as a whole, or for particular building types.

What happens after a retrofit is also important. The inhabitants' everyday practices and norms of comfort are often changed in parallel to retrofitting of the home. The expected savings are thus not often achieved (due to rebound effects). Engagement with this requires an understanding of broader norms related (1) to energy cultures and (2) to different types of energy-consuming practices. From a policy perspective this is not an easy task. However, several papers in this issue do suggest some promising approaches. In general these approaches take the starting point that practices and norms are collective. This means that changes in inhabitants' practices do not primarily occur in the head of individuals. Instead, these changes are formed along different organizational, social and infrastructural structures. Community projects, dialogue between owners and different types of intermediaries, as well as different types of social learning processes are constructive examples of policy initiatives. These kinds of initiatives need to become embedded into retrofit policy for the domestic sector, and need to be part of the routines that constitute a retrofit process.

The findings about what happens during the retrofit process are also presented in many of the papers. These examine how retrofits actually transpire in real life, which is often significantly different from the assumptions within policy. The reality is that retrofitting is a continuous process, which is negotiated against and in relation to different everyday practices and economic and technical possibilities. A better understanding of the variation in, and context of, real-life retrofitting is a critical component for policy and practice. There is a need to understand how to promote networks between many different types of institutions and actors. This will accelerate the move from the small-scale retrofit initiatives in many different countries to a widespread culture of retrofitting for a low carbon everyday life.