Background

The energy efficiency of buildings is significantly affected by the presence, actions and attitudes of building occupants. Unoccupied houses require little or no energy, however a great deal of energy is used to ensure the environmental conditions in the home (temperature, lighting, ventilation etc) are ‘comfortable’ for the occupants.

Thus, the way the occupants behave and interact with the building can have a massive impact on the energy used and the comfort levels achieved. The NHBC Foundation believes that there is a pressing need for more information on how end users interact with new homes and what impact this has on energy use and occupant comfort and satisfaction. This review was prepared by the Social Research Team at BRE for the NHBC Foundation. It was commissioned to examine current and previous research in this area and to identify any gaps in knowledge and specifically where further work is needed.

Objectives

The aim of this review is to provide an overview of research into occupant behaviour in domestic buildings. It will summarise and assess the relationship between occupant behaviour and the energy efficiency of domestic dwellings. It will also look at occupant feedback on new homes and their perceptions of micro-domestic energy systems.

The objectives are to:

• review research into end users of new homes
• assess the current and potential issues and problems
• identify gaps in knowledge and where further research is needed

This review examines five main areas:
Designing for the end user: An examination of research on controls and user interfaces and the importance of getting them right as technology and control systems become ever more complicated.

• Informing the end user: The role of domestic user guides. What research has been done in this area? What should they contain? In what format should the information be presented?
• The impact of the end user: How occupants interact with their homes and the impact of their behaviour on energy use, comfort and satisfaction.
• Feedback from end users: What occupants are saying about the latest homes on the market and what the latest examples of low energy homes are like to live in.
• Perception of micro-renewable systems: Drivers and barriers to investing in these technologies and an examination of how these systems are performing in the real world and how consumers perceive them.

This review outlines the main findings from an extensive literature review and input from experts at BRE.

Energy Use

Energy use in domestic buildings is determined by physical factors, such as building characteristics and local climate; and socio-demographic factors such as household composition and human behaviour. Approximately 27% of British carbon dioxide emissions come from the energy used in homes (Energy Saving Trust, 2010b). The typical household wastes approximately one-third of that energy each year (POST, 2005).

Although POST does not specify where this waste comes from, an Energy Saving Trust report (The Habits of a Lifetime) found that the most prolific habits that lead to wasted electrical energy were: 71% of consumers left appliances on standby, 67% boiled more water than needed in the kettle, 65% left electrical chargers plugged in and 63% forgot to turn lights off in unoccupied rooms.

In UK homes, energy use is split between heating and hot water (approximately 77%) and powering appliances/lights (approximately 23%) (POST, 2005). Domestic energy consumption has fallen in recent years, after a peak in 2004. Reasons for this reduction include high fuel prices, relatively warm weather, actions by consumers, such as making improvements to their homes (for example, insulation) and changes in behaviour, for example, turning electrical equipment off instead of leaving it on standby (Ofgem, 2010). British Gas figures show a 22% drop in household demand for gas as energy efficiency measures take effect (Centre for Economics and Business Research Limited, 2011). According to POST (2005), the two main  barriers to energy efficiency are technology and behaviour.

The Climate Change Act (2008) requires cuts in UK emissions of 80% by 2050 from 1990 levels (779.9 Mt CO2 e). More than an 80% reduction is expected to come from the housing sector to compensate for other sectors which would have difficulties making the cuts. This significant change means that it is vital to understand householders’ attitudes, perspectives, behaviours and the barriers to the take-up of the necessary actions.

Detailed analysis shows there is a path to achieving the necessary reductions
and that, by 2050, energy savings in buildings can equal the total energy
consumed in today’s transportation. It is clear that financial, behavioural and
knowledge barriers must be overcome for individuals, governments and
businesses to aggressively adopt energy saving options.’ (WBCSD, 2010)

Energy Efficiency

The house-building industry needs to move fast to make the necessary changes to improve energy efficiency. A culture change is needed and this will require an improved understanding of how buildings are used by occupants. New technologies, controls and innovative house designs can lead to occupants becoming bewildered and confused and so not gaining full advantage from the innovations.

It is important that occupants understand new technologies as the way occupants interact with buildings, and in particular, the building controls, can have a significant impact on the energy used and the comfort levels achieved. There is little evidence on how well some of the new technologies perform in real life or how they affect behaviour. The lack of information can lead to people becoming reluctant to invest in new technologies (Energy Saving Trust, 2010b). In addition, there is concern that many new homes are untried and untested within the context of mainstream housing in the UK. Many do not go through thorough monitoring and evaluation to check whether they achieve their designed performance targets (Bell, Wingfield, Miles-Shenton and Seavers, 2010).

Post-occupancy evaluations are important to gain an increased understanding of occupant behaviour in new homes. During post-occupancy, problems can be detected and feedback obtained to ensure that energy saving measures are fully optimised. Bell et al (2010) suggest that post-occupancy evaluations should become routine and the results fed back into the design process. Weaknesses in design could be overcome and it would allow greater opportunities for improved interaction and understanding between building providers and occupants. This would result in improvements in processes and products and allow innovations to really make a difference.

Behaviour

It is the occupants who determine how energy efficient a dwelling will be – even if the building is well insulated and the dwelling has an efficient energy source (Stevenson and Leaman, 2010). There are often large gaps between occupant and design expectations and the final energy performance of buildings. Some reasons for this are that many designers do not take into account how occupants use buildings, and solutions that look good at the design stage are often too complicated to be used effectively by building occupants (Pett and Guertler, 2004). Innovations in the design of buildings necessitate behaviour changes because people need to understand them and use them
in appropriate ways.

A report by BRE for the BRE Trust (Prior, Hadi and Brown, due for publication end of 2011), looks at attitudes to low flow taps in the light of the drive to low flow appliances, eg in the Code for Sustainable Homes: Technical Guide (Department for Communities and Local Government, 2010b). They found that consumers would not accept the lowest flow rates and in fact said that they would have these fittings changed if they found them in their new homes. BRE also found similar issues in post-occupancy evaluations on new homes, for example, for the Home Group 2009 (unpublished). A number of occupants were unhappy with their low energy light fittings after moving in and were having them replaced. This suggests that new low energy/low water appliances need to be perceived as acceptable by occupants, otherwise they will simply be ripped out and replaced.

Reducing energy use depends upon not only improving building performance, but also understanding the relationship between how occupants use the property and their particular personal circumstances. Personal circumstances can have many effects on the building’s energy use, for example, a single person out at work all day will have different energy needs to a family with young children who spend a large portion of their time in the house.

Human behaviour is varied and complex. There is considerable uncertainty about what motivates people to behave in an environmentally responsible way. Research has shown that there is no single general construct that predicts environmentally friendly behaviour (Oskamp et al, 1991, cited in McMakin, Malone, and Lundgren, 2002) and studies have shown no connection between people reporting concern for the environment and their own energy use (McMakin et al, 2002). Steg and Vlek (2008) argue that promoting behaviour change is more effective if the behaviour to be changed is carefully selected, the factors that cause the behaviour are examined, well-tuned interventions are applied and the effects of the interventions are systematically evaluated.

Even if the public is concerned about the environment, there is a reluctance to make significant changes in lifestyles and practices. A Department for Environment, Food and Rural Affairs (DEFRA) research survey of public attitudes and behaviours towards the environment (DEFRA, 2007) found that, while 75% of respondents reported that they were prepared to change their behaviour, only 5% said that they had actually reduced their car usage due to environmental concerns. Psychologists would argue that changing attitudes does not necessarily change behaviour, rather the opposite is often true (Abrahamse, Steg, Vlek and Rothengatter, 2005).

Psychology

It is widely recognised that social factors influence energy use in the home (McMichael, 2007). Several studies have indicated that, although everyday energy consumption is usually regarded as an individual act and while energy consumption may be undertaken by individuals, it is actually a social phenomenon (McMichael, 2007).

According to McMakin et al (2002), householders are constantly striving to use the same (or better) goods and services as friends, neighbours, etc. McMakin et al evaluated the social-psychological model of energy use, including Social Comparison Theory. This suggests that comparison, and even competition, with other people increases motivation to achieve something seen as possible, reduces uncertainty and helps determine standards of personal behaviour. Social Identity Theory proposes that people constantly strive for a positive self-image and being a member of a group is perceived as part of their identity. These theories suggest that emphasising a group identity can result in more cooperative behaviour and improved performance. They also indicate that a tailored approach should be taken to energy-reducing strategies with certain demographic variables (such as type of housing) and psychographic variables (such as constraints of occupants) being identified and targeted. They also suggest that changing people’s behaviour (in this case, to reduce energy use) might best be achieved by targeting groups of people rather than individually.

The social-psychological model of behaviour integrates societal, group and individual level processes. It provides support systems to assist behavioural change. Supporters of this model suggest that people are more likely to make permanent changes in their energy behaviours:

• if the new behaviours are easy and convenient to perform
• if they have the necessary skills and resources to change behaviours
• when their friends and neighbours are changing in similar ways
• when they make commitments to change in public setting

More specifically, there is an increased likelihood of people adopting energy efficiency behaviours if:

• they view energy efficiency as being a benefit to themselves rather than a curtailment;
• this is particularly true in terms of increased thermal comfort and health
• energy use and savings are visible and so provide goals and motives
  •    if others around them are engaged in similar behaviours or trying to meet similar
• goals information is provided in a vivid, salient and personal manner (McMakin et al, 2002)

These principles are important because they can usefully be applied to a range of behaviours outlined further in this review to increase the likelihood of occupants behaving in more energy-efficient ways, such as ways of informing end users how to operate systems and the use of smart meters to make energy use more visible. Changing an individual’s behaviour will be easier if others around them are also changing their behaviour in similar ways. The same may also be true of investing in low energy technologies, micro-renewable, insulation, etc