Estimating energy quantities using heuristics

In the qualitative study reported in Chapter 3, it was shown that householders probably do not make judgements about the energy consumption of appliances

using a full “rational” model of judgement making. Instead, they take short-cuts and save effort by simplifying the judgement process (Shah & Oppenheimer, 2008). It is assumed in this thesis that people do not know (or it is too difficult to find out) all the information that would be required to make a “rational” judge-ment. And, even if they did have all the relevant information, it would just be too difficult and take to much effort to organise and weigh up all that informa-tion appropriately to make a “rainforma-tional” judgement. Instead, they use the heuristic process of feature substitution (Kahneman & Frederick, 2002) in which they ac-cess limited amounts of information according to what information is most easily accessible and associated with energy estimates, and then base their energy esti-mate on that information.

A categorisation-based model of feature substitution in heuristic energy judge-ments was outlined in Chapter 2. According to the model, when judging the en-ergy consumption of appliances, people categorise the appliances according to features of the appliance (e.g. large appliances), judge how typical the appliance is of that category, and then map the appliance to the similar position in the ad hoc category (Barsalou, 2010) of high-energy-consuming appliances. Although all the energy perception studies given as examples in the model related to energy con-sumption perceptions, the categorisation model is potentially applicable to per-ceptions of energy savings too. People might categorise energy-saving measures according to certain features of the appliance or the measure (e.g. heat-reducing measures), judge how typical the measure is of that category (e.g. how much it reduces heat production in the appliance), and then map the measure to the sim-ilar position in the ad hoc category of high-energy-saving measures. For example, when judging whether switching off the lights (Measure A) will save more or less energy than installing energy-saving light bulbs (Measure B), people could cate-gorise the measures based on certain features of the measures and then map those features to energy savings. The feature of “reduces light production” might lead to the conclusion that A would save more than B; the feature of “reduces usage time” might also lead to the conclusion that A would save more than B; the fea-ture of “improves efficiency”, however, might lead to the conclusion that B would save more than A. Although this heuristic approach of feature substitution will not always produce the “correct” answer, it probably produces a good enough answer often enough that the benefits of simplifying the judgement outweigh the risk of occasionally producing an answer that is not good enough. In situations

where experts need to model energy consumption or savings with great accuracy they would probably not, of course, rely on these simple heuristics but would have computer software and training to help make their judgements. For the ma-jority of householders, however, precise accuracy is not important enough to go to huge amounts of effort and learning; heuristics are ideal.

6.1.3 Research questions

The research questions addressed in this study were:

How do people try to infer the energy savings of household energy-saving measures? In particular, what sources of information (cues) do they use to infer the effectiveness of energy-saving measures?

6.1.4 Study overview

In their survey-based study, Attari et al. (2010) found that participants estimated different quantities of energy for similar activities when asked to estimate energy consumption versus energy savings. Although the evidence was limited, they tentatively suggested that perceptions of energy consumption might differ from perceptions of energy savings by the way they are framed. The interviews con-ducted for the present study were concon-ducted at the same time as the interviews reported in Chapter 3. In the present study (Study 3), participants were asked about how they estimate the amount of energy saved, whereas, in Study 1, par-ticipants were asked about how they estimate the amount of energy consumed.

The Study 3 interviews were initially designed to capture only the effects of dif-ferently framing energy estimates, relative to the Study 1 interviews, according to whether the estimates were framed as energy use or energy savings. However, during data collection and the analyses, it became clear that estimating energy savings is different and more complex than estimating energy consumption so the two sets of interviews were analysed separately. Because there was little pre-vious research to inform the design of the interviews in Study 3, the researcher did not probe as deeply in some discussion areas as would be ideal so the con-clusions are tentative and would need further, in-depth qualitative research to strengthen them. However, the findings in Study 3 do correspond with the find-ings of Study 1 and also with the findfind-ings of van den Broek (2016). That cor-respondence along with the novelty of the findings give value to the reporting

of this study as a basis for generating future research questions and hypotheses.

The study also provided a sufficient basis for developing the quantitative studies reported in Chapter 7.

6.2 Method

Ten UK householders participated in semi-structured interviews that included simple card sort tasks. The audio recordings of the interviews were transcribed and then analysed using Thematic Analysis.

6.2.1 Participants

Ten householders from a large village in South-East England were recruited to participate in face-to-face interviews. Flyers asking recipients to share their thoughts about how they save energy in their daily lives were delivered to about 75 house-holds and then followed up by face-to-face requests. Appendix C provides ex-amples of the flyers and information sheets used to recruit participants. All other recruitment details were the same as reported for Study 1 in Chapter 3. Table 6.1 gives details of the Study 3 participants. All participants were white, all were British, and all were resident in the village when the interviews were conducted.

6.ExploringPerceptionsofEnergySaving(Study3)147

PS01 PS02 PS03 PS04 PS05 PS06 PS07 PS08 PS09 PS10

Sex Female Female Female Female Male Female Male Female Male Male

Age 20s-30s 20s-30s 50s 30s-40s 30s 20s-30s 40s-50s 30s 60s 60s

Job Sales Housewife Unknown

End terr Semi Detached Mid-terr Mid-terr End terr Detached Detached Bungalow Detached Mains

Gas

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Heating Gas Gas Gas Gas Gas Gas Gas Gas Gas Gas

Owns House

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Owns Car

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Monitor Never Current Never In the past

Six of the ten participants in the present study had past or current experience of using an energy monitor, though they varied in levels of reported engagement.