Assessing the EU Energy Efficiency Label for Appliances: Issues, Potential Improvements and Challenges

Citation: de Ayala, A.; Solà, M.d.M. Assessing the EU Energy Efficiency Label for Appliances: Issues, Potential Improvements and Challenges. Energies 2022,15, 4272. https://doi.org/10.3390/en15124272 Academic Editors: Luis Maria Abadie and Ibon Galarraga Received: 9 May 2022 Accepted: 7 June 2022 Published: 10 June 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). energies Article Assessing the EU Energy Efficiency Label for Appliances: Issues, Potential Improvements and Challenges Amaia de Ayala 1,2,* and María del Mar Solà1,2 1Department of Applied Economics, Faculty of Social and Communication Sciences, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain 2Basque Centre for Climate Change (BC3), Scientific Campus of the University of the Basque Country (UPV/EHU), Sede Building 1, 1st floor, 48940 Leioa, Spain; [email protected] *Correspondence: [email protected]; Tel.: +34-946-015571 Abstract: The EU Energy Efficiency (EE) label for appliances, readjusted in March 2021 (Directive 2017/1369/EU), is a key instrument for nudging consumers towards more energy-efficient purchases. However, its effectiveness depends on its design, the information provided and consumers’ understanding of and trust in it. This paper seeks to contribute to the assessment of the EE label for appliances and to identify issues, potential improvements and challenges for successfully nudging consumers towards highly energy-efficient choices. To that end, 33 in-depth interviews have been conducted with three different groups (citizens, appliance retailers and experts in energy) to ascertain the opinions and experiences of different agents as to consumers’ preferences and opinions on EE and energy consumption. We focus on purchasing decision-making by Spanish consumers for the three main appliances: washing machines, fridges and dishwashers. The EE label for appliances seems to be well-known and reliable for consumers. The main weakness lies in people’s understanding of its content rather than in its design. The coloured alphabetical EE scale seems to be well understood and the restored A–G scale of the readjusted label positively valued. However, we find comprehension issues with regard to the information on energy consumption and the technical data at the bottom of the label. Monetary information on energy consumption seems to facilitate consumers’ understanding, but it is technically challenging due to the complexity of the unit of measurement. Results are discussed, taking into account the relevant literature. Keywords: energy efficiency; energy label; energy consumption; purchasing decision-making; appliances; in-depth interviews 1. Introduction Energy efficiency (EE), defined as improvements in the efficiency with which energy is used to provide a service, has become crucial in recent years for achieving the EU target of 32.5% energy savings by 2030 (Energy Efficiency Directive 2018/2002). EE has several strengths and benefits, but these are not usually enough to encourage consumers to make the most energy-efficient choices. Although EE seems to be financially profitable for consumers, they do not usually invest as much as may seem rational [ 1 – 3 ]. This is known as the energy efficiency gap. The EE gap can be explained by failures of several types, including behavioural failures, informational failures and other market failures [ 3 – 5 ]. Informational failures are one of the most common types: they involve situations in which consumers lack or misunderstand the information needed to make optimal choices. There are various policy instruments for coping with such failures: energy certificates and labels, information feedback tools and energy audits [ 4 – 6 ]. EE labels are one of the easiest and cheapest ways to successfully nudge consumers towards more energy-efficient choices [ 4 , 5 ]. This is particularly important for household appliances, which account for 25.6% of the total energy consumption of Spanish households [7]. Energies 2022,15, 4272. https://doi.org/10.3390/en15124272 https://www.mdpi.com/journal/energies Energies 2022,15, 4272 2 of 25 A new European directive on EE labels came into force in March 2021 for household appliances (Directive 2017/1369/EU). It requires EE labels to be displayed on energyrelated appliances at the point of sale with a scale from A to G, in different colours (green for highly energy-efficient appliances and red for less efficient ones). This original energy scale was reintroduced via a new regulation passed in January 2017 in the light of evidence that the A+++–D scale was not effective [ 8 ]. The main changes in this new directive compared to the previous one (Directive 2010/30/EU) are: (i) the scale of EE labels now ranges from A–G instead of A+++–D; (ii) energy consumption information for washing machines and dishwashers now appears in terms of use instead of per year; and (iii) the interface of the icons at the bottom of the label is different (see Figure 1). Energies 2022, 15, x FOR PEER REVIEW 2 of 25 to successfully nudge consumers towards more energy-efficient choices [4,5]. This is particularly important for household appliances, which account for 25.6% of the total energy consumption of Spanish households [7]. A new European directive on EE labels came into force in March 2021 for household appliances (Directive 2017/1369/EU). It requires EE labels to be displayed on energyrelated appliances at the point of sale with a scale from A to G, in different colours (green for highly energy-efficient appliances and red for less efficient ones). This original energy scale was reintroduced via a new regulation passed in January 2017 in the light of evidence that the A+++–D scale was not effective [8]. The main changes in this new directive compared to the previous one (Directive 2010/30/EU) are: (i) the scale of EE labels now ranges from A–G instead of A+++–D; (ii) energy consumption information for washing machines and dishwashers now appears in terms of use instead of per year; and (iii) the interface of the icons at the bottom of the label is different (see Figure 1). This paper seeks to contribute to the assessment of the EE label for appliances and to identify issues, potential improvements and challenges for successfully nudging consumers towards highly energy-efficient purchases through the EE label. This is done in various steps. First, we seek to understand the role of EE in consumers’ decisionmaking on the purchase of appliances. Second, we assess how widely accepted the EE label is among consumers (whether they recognise it, understand it, trust it and take it into account). This includes an evaluation of the readjusted EE label. Finally, we look for possible improvements in the way in which energy consumption information is presented, and in particular, whether monetary information on energy consumption can be included on the label. Figure 1. The old energy efficiency label (A+++–D scale) (Directive 2010/30/EU) and the new energy efficiency label (A–G scale) for washing machines, which entered into force in March 2021 (Directive 2017/1369/EU). Figure 1. The old energy efficiency label (A+++–D scale) (Directive 2010/30/EU) and the new energy efficiency label (A–G scale) for washing machines, which entered into force in March 2021 (Directive 2017/1369/EU). This paper seeks to contribute to the assessment of the EE label for appliances and to identify issues, potential improvements and challenges for successfully nudging consumers towards highly energy-efficient purchases through the EE label. This is done in various steps. First, we seek to understand the role of EE in consumers’ decision-making on the purchase of appliances. Second, we assess how widely accepted the EE label is among consumers (whether they recognise it, understand it, trust it and take it into account). This includes an evaluation of the readjusted EE label. Finally, we look for possible improvements in the way in which energy consumption information is presented, and in particular, whether monetary information on energy consumption can be included on the label. This all will be analysed from three different perspectives to ascertain the opinions and experiences of different agents related in different ways to energy consumption and Energies 2022,15, 4272 3 of 25 EE: (i) that of the public as users of household appliances; (ii) that of household appliance retailers as experts in purchasing decision-making by customers; and (iii) that of academic experts as specialists in the field of energy research. The public is expected to answer the questions based on their own behaviour and reactions, while sellers and experts should provide insights into the consumer tendencies and habits based on their experience and specialist knowledge. This enables us to reflect on the acceptability of the previous and restored EE labels and to make recommendations for the design of an effective label to encourage consumers to purchase highly energy-efficient appliances. There is previous research assessing the EE label in general [ 9 , 10 ] and focusing on particular aspects of it such as the design of the EE scale [ 10 – 12 ] how energy information is presented [ 13 – 15 ] and how it is understood, perceived and considered [ 16 , 17 ]. The relevant literature has tested the effectiveness of presenting energy consumption information as monetary information [ 14 , 18 , 19 ] or health-related information [ 20 ]. In the appliances market, there are recent studies that measure the effect of providing monetary information in terms of energy cost [14,19,21,22] or as energy savings [15] as a way of promoting EE. Previous assessments of the EE label provide mainly quantitative evidence and may lack a clearly thought-out explanation of the motivations behind each preference and choice. As pointed out by Bavaresco et al. [ 23 ], energy research may still lack social science approaches to improve its outcomes and assess the human dimension of energy use. In Spain, an earlier study [ 16 ] explores the factors that motivate consumers to purchase energyefficient goods across different sectors (households, the accommodation sector and private service companies) and products (appliances, heating, ventilation and air-conditioning and cars). The present study focuses mainly on identifying issues, potential improvements and challenges in the EE label for appliances from three different viewpoints (the general public, retailers and experts in energy research) to provide guidance for effective EE labels. It also provides a comparison between the readjusted label (in use from March 2021) and the previous one. Qualitative analysis may give significant insights into these aspects from different standpoints since it provides a deeper understanding of how the EE label is understood, why (and why not) it is taken into account and how it can be improved. We use a number of in-depth interviews with members of the general public, retailers and experts in the field of energy research to ascertain their opinions, experiences, expectations and knowledge regarding consumer behaviour towards EE and EE labels. We focus on purchasing decisionmaking by Spanish consumers and on three main appliances—fridges, washing machines and dishwashers—as they account for 30.6%, 11.8% and 6.1% of energy consumption in Spanish households, respectively [7]. Section 2looks at previous publications assessing the EU EE label and ways to improve it. Section 3describes the methodology applied in this study. Section 4presents our findings. Section 5discusses them and concludes. 2. The Effectiveness of the EU Energy Efficiency Label for Appliances Research into understanding consumer reactions to EE labels for vehicles and household appliances has been growing in recent years due to the mandatory implementation of EE labels in these markets and increasing energy and environmental concerns (see [ 5 ] for a review). In the appliances market, there is a growing body of research on estimating EE label price premiums, e.g., for washing machines, dishwashers and refrigerators in Spain [ 24 – 26 ]; for washing machines in Switzerland [ 27 ]; for washing machines, refrigerators and air conditioners in China [ 28 – 30 ]; and for refrigerators in Germany [ 31 , 32 ] and the US [ 33 – 35 ]. These studies estimate a positive willingness to pay for highly energy-efficient appliances, although its scale varies from country to country and in line with different consumer profiles, years of study and appliance types [29,36]). Other studies focus on assessing EE labels and particularly on how their design and the information presented can affect their effectiveness and therefore decision-making by consumers. Table 1presents a summary of studies assessing the EU label for appliances in Energies 2022,15, 4272 4 of 25 terms of label design and type (and format) of information. With regard to label design, Egan and Waide [ 9 ] compare energy labelling programmes in nine countries and highlight that labels which represent EE levels via discrete categories (stars, letters or numbers) are preferred over those that use a continuous scale. Heinzle and Wüstenhagen [ 11 ] carried out a discrete choice experiment in Germany concerning the EE scale and concluded that German consumers are more willing to pay a higher premium for TVs with the highest ratings on the A–G scale than on the A+++–D scale. Waechter et al. [ 10 ] found that not only the letter range used in the scale but also the number of EE categories can influence consumers’ choices. They tested the impact of a shorter EE scale with just 3 EE classes (A–C scale) for different appliances (freezers, lamps and coffee machines) in Switzerland and found that it increased the perceptions of EE gains in high-EE products, which could motivate consumers to choose the most energy-efficient products. Waide et al. [ 37 ] used questionnaires, focus groups and in-depth interviews to analyse the understanding of consumers (from London, Prague and Paris) with regard to revised energy labels for appliances (fridge-freezers, washing machines, dishwashers and television sets) introduced at the end of 2011 (Directive 2010/30/EU). Their evidence shows that higher EE classes under the previous A–G scale implemented in 1995 are much more motivating for consumers than those under the A+++–D scale. London Economics [ 12 ] assessed alternative EE label designs for different appliances (televisions, washing machines and light bulbs) in seven EU Member States by means of an online behavioural experiment and a bricks-and-mortar experiment. They found that consumers’ understanding does not vary between A–G and A+++–D scales, but they found evidence that more consumers choose energy-efficient appliances when the A–G scale is used than under the A+++–D scale. The same study notes that the EE scale is better understood when it is represented by letters than by numbered frames. De Ayala et al. [ 16 ] also find that the coloured alphabetical grid is much appreciated in Spain. There is a growing body of research assessing the energy-related information presented on labels and how to influence consumers’ choices. De Ayala et al. [ 16 ] recognise various ways of facilitating consumers’ understanding of energy consumption, such as using a scale to tell whether consumption is low or high and presenting monetary information on energy consumption. However, several issues can be identified with regard to measuring monetary information, such as the market price of energy and the reference used. Various ways of providing monetary information are noted in the literature, in terms of energy cost or energy savings. For energy cost, Kallbekken et al. [ 18 ] used a field experiment to test the effectiveness of providing lifetime energy cost information on tumble dryers and freezers. They found no effect for freezers but a decrease in the average energy consumption of tumble dryers sold when labels provide monetary energy cost information and sales staff have training on EE-related issues. Similarly, using an online field experiment for washing machines, Deutsch [ 38 ] found a small but significant reduction in energy use when consumers receive additional information on life-cycle costs. Bull [ 39 ] concludes that information on running costs and emissions increases willingness to pay and that lifetime running cost information is more effective than per annum information. Heinzle [ 40 ] conducted a discrete choice experiment and found that consumers will pay a higher price premium for televisions when ten-year monetary costs are displayed but a lower premium when one-year cost information is displayed (compared to non-monetary EE information). In line with these results, Blasch et al. [ 21 ] conducted a randomised control trial in Switzerland and showed that energy and investment literacy are positively correlated with the probability of choosing the fridge with the lowest lifetime energy cost. Energies 2022,15, 4272 5 of 25 Table 1. Summary of studies assessing EU labels for appliances. Study Concept Tested Methodology Appliance/s Result Design Heinzle and Wüstenhagen [11] EE scale Discrete choice experiment Television An A–G scale is more effective in guiding consumers’ decisions towards energy-efficient products Waechter et al. [10] EE scale Online experiments Freezers, lamps, coffee machines A shorter scale with 3 classes (A–C) increases consumers’ motivation to choose the most energy-efficient products Waide et al. [37] EE scale Questionnaires, focus groups and in-depth interviews Fridge-freezers, washing machines, dishwashers, televisions High EE classes are more motivating on an A–G scale than on an A+++–D scale London Economics [12] EE scale Online behavioural experiment and bricks and mortar experiment Televisions, washing machines and light bulbs •Labels with an A–G scale lead more consumers to choose energy-efficient products than an A+++–D scale •Consumers understand alphabetical EE frameworks better than numerical ones Egan and Waide [9] EE scale Market research Appliances in general Discrete EE categories (stars, letters or numbers) are more effective than a continuous scale de Ayala et al. [16] EE scale Focus groups and in-depth interviews Appliances, heating and cooling systems and cars The coloured alphabetical scale is valued positively Content de Ayala et al. [16]Monetary information on energy consumption Focus groups and in-depth interviews Appliances, heating and cooling systems and cars Monetary information is valued positively but there are issues in measuring it (energy price and frequency of use) Kallbekken et al. [18]Ten-year energy cost information Field experiment Tumble dryers and freezers Ten-year energy cost information is effective for tumble dryers but no effect is found for freezers Deutsch [38] Life cycle cost information Online field experiment Washing machines Life cycle cost information results in a reduction in energy use of 0.8% Bull [39] Running cost information (per year and lifetime) and emissions information Stated preference survey Washing machines •Running cost and emissions information increases willingness to pay for washing machines •Lifetime running cost information is more effective than per annum information Energies 2022,15, 4272 6 of 25 Table 1. Cont. Study Concept Tested Methodology Appliance/s Result Content Heinzle [40] Ten-year energy cost information vs. per annum information Discrete choice experiment Televisions A higher price premium is found when ten-year cost information is presented and a lower one when per annum information is shown Blasch et al. [21]Lifetime energy cost information Randomised control experiment Fridge Energy and investment literacy is positively correlated with the probability of investing in high-efficiency fridges Solàet al. [41]Lifetime (ten-year) energy cost information Field experiment Washing machines, fridges, dishwashers and tumble dryers Lifetime energy cost information is effective in promoting the purchase of A+++ tumble dryers and A++ washing machines, fridges and dishwashers Allcott and Sweeney [42]Energy cost information per year + sales staff Natural field experiment Water heater Energy cost information and information provided by sales staff are effective when treated jointly Carroll et al. [43]Five-year energy cost information Field Experiment Tumble dryers No effect is found Skourtous et al. [19] Annual operating cost Discrete choice experiment Fridge No effect is found d’Adda et al. [22]Yearly or lifetime energy cost Field experiment Fridge •Energy cost information directs purchases towards cheaper products in lower EE classes, but with similar energy and total costs •There is a trade-off between economic savings and higher search costs Solàet al. [14]Lifetime (ten-year) energy savings information Field experiment Washing machines, fridges and dishwashers Lifetime energy savings information is useful for promoting the adoption of high-efficiency washing machines and fridges, but no effect is found for dishwashers Stadelmann and Schubert [15]Lifetime monetary information (cost and/or savings) Online field experiment Freezers, tumble dryers, vacuum cleaners Monetary information is useful in increasing the adoption of highly efficient tumble dryers and vacuum cleaners, but no effect is found for freezers Source: Own work. Energies 2022,15, 4272 7 of 25 In a field experiment in Spain, Solàet al. [ 41 ] found that lifetime energy cost information is effective in promoting the adoption of high-efficiency tumble dryers (A+++) and of A++ labelled washing machines, fridges and dishwashers. A similar field experiment was run by Allcott and Sweeney [ 42 ], who showed that energy cost information per year and sales incentives need to be treated jointly to boost energy-efficient purchases. By contrast, a field experiment conducted by Carroll et al. [ 43 ] found that providing 5-year energy cost information has no effect on tumble dryers. Finally, Skourtos et al. [ 19 ] ran a choice-based experiment in Greece and found that including the annual operating cost of fridges has no effect on consumers’ choices. They therefore proposed using energy savings campaigns to promote the purchase of high-efficiency appliances. A recent study [ 22 ] involved a field experiment with an Italian online retailer for refrigerators purchases and found that: (i) adding yearly or lifetime energy cost information on the label shifts purchases from top-ranked to low EE classes with lower prices but similar overall energy and total costs, since the distributions of energy costs of different EE classes overlap; (ii) providing monetary information extends product searches among consumers, with more attention paid to low EE products. Given this, the authors call into question the effectiveness of providing running cost information on labels. Concerning monetary information on energy savings, Solàet al. [ 14 ] conducted a field experiment to analyse the effectiveness of providing lifetime energy savings information for washing machines, fridges and dishwashers in Spain. They found that giving monetary information through a monetary label is effective in promoting high-efficiency washing machines, while both monetary information provided by staff alone and the combination of a monetary label and information from sales staff seem to be effective in promoting purchases of high energy-efficiency fridges. Stadelmann and Schubert [ 15 ] ran a field experiment to compare the effectiveness of labels in different scenarios (no label, EU energy label and lifetime-oriented monetary energy label) for freezers, tumble dryers and vacuum cleaners. The monetary label indicates lifetime energy savings or costs depending on the energy consumption of the product. They found that the presence of either label increases sales for high-efficiency tumble dryers and vacuum cleaners, but not for freezers. The other (non-energy) information on the energy label has also been questioned in some studies such as de Ayala et al. [ 16 ] and Waide et al. [ 37 ]. They highlight that consumers find it hard to understand the technical information in the form of icons presented at the bottom of the label (e.g., noise level, capacity, spin efficiency class, water consumption) and that they do not even take this information into account in their purchasing decision-making. 3. Methodology Data were collected via semi-structured guided interviews and in-depth interviews applied to three groups: members of the general public as users of household appliances, retailers experienced in purchasing decision-making by customers and experts in energyrelated research. The interview method, the subsampling method, the topic guideline and the data analysis are outlined below. 3.1. In-Depth Interviews and Sample An in-depth interview (IdI) is a pre-arranged, direct, personal interview in which a single participant is questioned by an experienced interviewer to talk in-depth about the topic under investigation and uncover underlying motivations, beliefs, attitudes and feelings on that topic. The main idea is to identify and understand the pattern of thoughts, emotions and behaviour of an individual participant. IdIs are often referred to as semi-structured interviews because the researcher retains some control over the direction and content to be discussed, but participants are free to elaborate or take the interview in new but related directions [ 44 ]. IdIs are usually carried out face-to-face so that a rapport can be created with interviewees. The interview is conducted Energies 2022,15, 4272 8 of 25 using a discussion topic guide which helps to flush out the respondent’s views through open-ended questioning [45–47]. The aim of the sampling design in IdIs and qualitative research, in general, is to gather enough data to give an accurate understanding of the topics under investigation and the different views that are present in the study population. Furthermore, the sample tends to be constructed “purposively” rather than drawn randomly from a sample frame. Purposive sampling (also known as targeted or judgement sampling) covers a wide variety of characteristics referring to the construction of the sample in some way that facilitates the satisfaction of the research questions [ 46 , 48 ]. A typical IdI in social sciences uses a target sample of between 10 and 50 interviews [48]. In total, 33 IdIs were conducted in Spain between April and May 2021 to assess the role of EE and EE labels in purchasing decision-making by consumers for appliances from the perspectives of different participants: 11 for members of the public, 10 for retailers and 12 for experts. The IdIs for the public and for retailers were carried out face-to-face by a survey company (CPS) (https://www.cps2000.com, accessed on 1 November 2021) and lasted about 30 min each. The members of the public and retailers interviewed were from the city of Bilbao and other municipalities in the province of Bizkaia (Spain). They were paid ( € 10) to encourage their active participation. We ourselves conducted the IdIs for experts online, as they came from different parts of Spain. They also lasted about 30 min. The members of the public comprised 11 homeowners who had bought a new appliance (washing machine, fridge or dishwasher) in the last 5 years. Five of them had also benefited from Spain’s RENOVE household electrical appliance renewal programme in any of their purchases, so we were able to look at the effect of this programme on their purchasing decision-making. The RENOVE programme is promoted by the Spanish Institute for Energy Diversification and Saving (IDAE). Through it, each regional autonomous community offers users financial incentives to replace old appliances with new, more efficient ones (i.e., with the highest EE level). The 11 individuals selected were recruited strategically to ensure heterogeneity regarding gender, age, education level, household composition, employment situation and household income level. The recruitment criteria for the sample of the members of the public can be seen in Table A1 of Appendix A. The sample of retailers consisted of 10 individuals selected in order to ensure that household retail appliance-selling establishments of different types and with differing turnovers in the province of Bizkaia (small, medium and large) were represented (see Table A2 of Appendix A). The sample of experts comprised 12 Spanish academics from different research centres and universities, covering various areas of expertise in the field of energy (energy and climate change policies, energy modelling, energy markets and EE) while ensuring gender balance (see Table A3 of Appendix A). Experts were contacted via email to explain the study and its objective. Then, an appointment was made for the online interview. The reason for choosing strategic recruitment criteria rather than trying to aim for better statistical representativeness is that the objective of our study is to understand the motivations, experiences and type of arguments behind each question, rather than to measure preferences quantitatively (which can be done better by conducting a survey). We selected participants who we expected to have different experiences and perspectives (e.g., households with children versus households without children, retailers from large establishments versus retailers from small establishments or experts in the field of EE versus experts in other energy-related topics), and who we thus expected to have different opinions on EE and EE labels for appliances. Targeted sampling is a common sampling strategy in qualitative research [16,17,49,50]. Energies 2022,15, 4272 9 of 25 3.2. Topic Guideline and Data Analysis For all three groups, the interviews were semi-structured with open-ended questions, allowing for discussion with the interviewee rather than following a straightforward question-and-answer format. The IdIs followed a detailed topic guide with a list of questions to make sure that the pre-defined list of topics was covered [45–47]. A general common guideline for all three groups was prepared to allow comparison between their perspectives regarding the various topics, but questions were tailored to each particular group by rephrasing them or adding further points in accordance with the target audience. The general common guide comprises 5 sections. The first section (“Appliances”) seeks to identify the main appliances in Spanish households and the second (“Purchasing decision-making”) seeks mainly to identify the key attributes that influence purchasing decision-making by consumers for appliances (e.g., “What are the key factors that consumers take into account when buying a new appliance?”,“Do consumers take EE labels into account when buying a new appliance?”). The third section (“Energy efficiency and energy consumption”) asks what consumers understand by EE, what consumers can do to reduce the energy consumption of appliances (in IdIs for the public and experts only) and what the general buyer profile is (gender, age, household composition, household income level, education level, etc.) for high-efficiency appliances (in IdIs for retailers and experts only). In this section, experts are also asked to reflect on the effectiveness of intervening in the purchase decision versus in decisions on energy use (“Which do you think can be more effective in promoting energy savings: intervening in the purchase decision and/or intervening in the energy use? Why?”). The fourth section (“Energy efficiency label for appliances”) assesses the acceptability of the EU EE label for appliances: whether consumers are familiar with it, understand it, use it and trust it. This includes the assessment of the readjusted EE label in use since March 2021. The fifth section (“Possible changes”) covers potential improvements in the EE label for appliances so as to promote EE (“Do you think there is room for improvement in the EE label? What? How? Why?”). We asked particularly about the possibility of providing monetary information on the energy consumption of appliances (“Do you think it would be useful to have visible monetary information on the energy consumption of the appliance (in euros rather than kWh) when buying? Why?”) and about the terms (cost or savings in euros) and units (per year, per month, per use, lifetime, etc.) in which that monetary information should be shown. Finally, we also asked about other potential ways to effectively inform about the energy consumption and EE of appliances (“Do you think there is any other way to inform about the energy consumption and efficiency of appliances apart from the current energy efficiency label? Which one? Why?”). The IdIs for retailers had an extra section focusing on the role of sales staff in purchasing decision-making by consumers (what type of information consumers usually request, what they think is the most effective way to inform customers about EE, etc.) and the effect of Spain’s RENOVE subsidy programme for appliance renewal on their sales. It is important to highlight that members of the public answered questions with regard to their own behaviour and opinions towards EE, but retailers and experts had to answer thinking of how consumers or customers behave in this regard based on their experience and specialist knowledge. The complete detailed topic guide, including the full list of questions asked and an indication of to whom each question was addressed, can be found in Appendix B. All IdIs were digitally recorded and transcribed to text. Content analysis was used to systematically transform this large amount of text into a highly organised, concise summary of key results [ 45 , 51 ]. A table was created following the topic guideline to include all comparable information in the same structure. Each column in the table refers to a single interviewee, while each row shows the information on a specific question. The information collected was assessed on a macro level in search of similar patterns, concepts and general themes [52,53]. Energies 2022,15, 4272 16 of 25 be less striking for consumers. The literature includes many more studies that propose monetary information in terms of energy cost than energy savings. With regard to units of measurement, we identify a slight preference for monetary information (in terms of cost or savings) to be presented per year, as this enables different types of appliances to be compared in the same unit and means that monetary amounts for longer periods of years or even for the whole useful lifetime can be determined. In the literature, the vast majority of studies use lifetime-oriented monetary information. This might be because providing information for a long period may have more impact on purchasing decisions [ 39 , 40 , 63 ]. However, we find that consumers tend not to trust the reported lifetimes of appliances. The unit per use/number of uses, as currently used on the label to provide energy consumption information for washing machines and dishwashers, appears not to have been quantitatively tested yet in the literature. It is important to note that efforts to reduce energy consumption in the residential sector should not focus only on improving the EE label to encourage the purchase of high energy-efficiency appliances but also on day-to-day energy-saving behaviours [ 64 , 65 ]. All the experts interviewed agree that to achieve substantial energy reductions and mitigate climate change, policy efforts should be focused on both investment in EE and energy use in the home. Indeed, the literature has shown that investments in EE and user behaviour are not independent and do not necessarily go in the same direction [8,58,62,64]. In addition to the EE label, rebate programmes such as Spain’s RENOVE household electrical appliance renewal programme seem to be a useful way of encouraging consumers to make energy-efficient purchases. Indeed, our respondents believe that such programmes have a clear positive impact on the sales of high energy-efficiency appliances. This is consistent with previous studies in Spain [66] and elsewhere [34,67,68]. The role of sales staff and information campaigns on EE also seems also to be crucial, since we find that EE is not the chief factor taken into account by consumers in their appliance purchasing decisions. The positive influence of explanations by retailers on final purchasing decisions by consumers has been observed in the literature [ 14 , 18 , 69 ]. However, the sales staff interviewed generally require training on EE aspects in order to have an effective impact on their customers’ decision-making. Measures focusing on energy use were also seen as necessary and complementary by the experts interviewed, e.g., apps or websites that identify which appliance consumes the most electricity and provide specific advice on how to reduce consumption (see [5,61,62] for a review on EE policies). 6. Conclusions Increasing EE is a major goal for the coming years. For it to be achieved, households have to purchase energy-efficient appliances. The EU EE label for appliances is key in this, but its effectiveness depends on its acceptability, i.e., the extent to which consumers recognise, perceive and understand the information on the label and take it into account in their purchasing decisions. This paper seeks to contribute to this goal by identifying issues, potential improvements and challenges concerned with the label with a view to nudging consumers towards high energy-efficiency choices. To that end, we have carried out a qualitative analysis based on in-depth interviews with different agents in Spain: members of the public, appliance retailers and academic experts in the field of energy. Based on our diagnosis of the EE label for appliances, we conclude that it is generally well-known, regarded as reliable and generally useful by consumers. However, most consumers still seem unfamiliar with the readjusted format of the EE label for appliances. In general, the main issue lies in the understanding of the content presented on the label rather than in the design itself. The coloured alphabetical EE scale seems to be liked and well understood. Moreover, the restored A–G scale of the readjusted label seems to be rated positively. However, we find comprehension issues with regard to (i) the information on energy consumption (both in kWh per year and in kWh per number of uses); and (ii) the technical information, since consumers do not understand the units in which they are measured. To Energies 2022,15, 4272 17 of 25 reduce these information asymmetries, monetary information about energy consumption (though it is not clear whether as a cost or a saving) seems to help consumers understand, but it is technically challenging to provide due to the complexity of the unit of measurement (energy cost or energy savings per month, per year, over the useful lifetime or per number of uses). For technical information, more clarity on what each technical symbol means is recommended, as are reference levels to allow for comparisons. However, this is also technically demanding and requires various assumptions to be made. Our approach has enabled us to consider the heterogeneity of preferences and experiences and to highlight motivations which would be overlooked in quantitative studies. Nonetheless, it may not be possible to generalise our findings to the whole population, as can be done with quantitative methods. Further research could be supplemented and supported by a quantitative analysis to assess, on a larger scale, some of the issues with the label identified here and some of the policy instruments briefly discussed. Author Contributions: Conceptualization, A.d.A.; Data curation, A.d.A. and M.d.M.S.; Formal analysis, A.d.A.; Funding acquisition, A.d.A.; Methodology, A.d.A. and M.d.M.S.; Supervision, A.d.A.; Validation, A.d.A.; Writing—original draft, A.d.A. and M.d.M.S.; Writing—review & editing, A.d.A. and M.d.M.S. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by Fundación Ramón Areces under the project entitled “La toma de decisiones de los hogares en eficiencia energética: determinantes y diseño de políticas”. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Acknowledgments: The authors acknowledge the support of Fundación Ramon Areces under XVIII Concurso Nacional para la Adjudicación de Ayudas a la Investigación en Ciencias Sociales. This study was conducted as part of the project entitled “La toma de decisiones de los hogares en eficiencia energética: determinantes y diseño de políticas”. Conflicts of Interest: The authors declare no conflict of interest. Appendix A. Interviewees: Members of the Public, Retailers and Experts Energies 2022,15, 4272 18 of 25 Table A1. Sample of members of the public. Interviewee Appliance Purchased RENOVE Programme Gender Age Education Level Household Composition Employment Situation Household Income Level (€/Month) 1Fridge (4 years ago) NO Female 37 University Married couple (pregnant) Unemployed 2500 2 Washing machine (3 years ago) Fridge (3 years ago) Dishwasher (2 years ago) NO Female 53 Vocational training Couple with 3 children Hotel industry 2000 3Washing machine (4 years ago) NO Female 61 Vocational training Living alone Retired 800 4Washing machine (4 years ago) Dishwasher (2 years ago) YES Female 38 University Married couple with 3 children Doctor 5000 5Fridge (1 year ago) YES Male 39 University Married couple with 2 children Employee 4500 6Washing machine (1 year ago) Fridge (1 year ago) NO Male 24 Vocational training Living alone (recently emancipated) Employee 1900 7 Washing machine (3 years ago) Fridge (3 years ago) Dishwasher (2 years ago) YES Female 68 Vocational training Living alone Retired 700 8Washing machine (3 years ago) Fridge (4 years ago) YES Male 40 Vocational training Couple with 2 children Cleaning service 2000 9Washing machine (<1 year ago) Fridge (3 years ago) YES Male 37 University Living with parents Self-employed 3600 10 Washing machine (1 year ago) Dishwasher (5 years ago) NO Male 56 University Married couple with 2 children Financier N/A 11 Washing machine (<1 year ago) Fridge (<1 year ago) Dishwasher (<1 year ago) NO Female 29 University Couple (recently emancipated) Administrative 900 Energies 2022,15, 4272 19 of 25 Table A2. Sample of retailers. Interviewee Type of Establishment 1 Small 2 Medium 3 Small 4 Medium 5 Small 6 Large 7 Large 8 Small 9 Small 10 Medium Table A3. Sample of experts. Interviewee Topic Position 1 Energy and climate change policies Senior consultant 2 Energy modelling Lecturer 3 Energy markets Lecturer 4 Energy and climate change policies Senior consultant 5 Energy efficiency Senior lecturer 6 Energy and climate change policies; energy modelling Professor 7 Energy efficiency Senior lecturer 8 Energy modelling Professor 9 Energy markets Deputy Director 10 Energy efficiency Senior consultant 11 Energy modelling; energy efficiency Professor 12 Energy modelling Senior researcher Appendix B. Guideline of the Interviews (Translated into English) The in-depth interviews used the following general guideline. Note: At the end of each question or section, the addressees (members of the public, retailers or experts) are specified in brackets. Appliances: 1. What are the main appliances at your home/in Spanish households/at your retailer? Could you please sort them in order of importance? Why did you choose this order? (Public, Experts, Retailers) 2. Please sort washing machines, dishwashers and fridges into the order of importance for your household/Spanish households/customers? Why did you choose this order? (Public, Experts, Retailers) Purchasing decision-making The following questions refer to three main appliances: washing machines, fridges and dishwashers. 1. How long ago (in years) did you last buy a washing machine/fridge/dishwasher for your home? (Public) Energies 2022,15, 4272 20 of 25 2. Who made the decision to buy the new appliance? Did you make it alone or with someone else? With whom? Why? (Public) 3. Why did you not benefit from the RENOVE programme when purchasing the new appliance? (Members of the public who did not benefit from the RENOVE programme) 4. What attributes did you/consumers/customers consider when buying the new appliance (e.g., price, brand, energy consumption)? (Public, Experts, Retailers) 5. Did you/consumers/customers take the energy efficiency label into account when buying the new appliance? Why? (Public, Experts, Retailers) 6. What is the general energy efficiency level of new appliance/s that you/consumers/ customers purchase? High, medium or low? (Public, Experts, Retailers) 7. If you currently want to buy a new appliance for your home, would you consider the same attributes and in the same order as in your last purchase? Or would you change something? What and why? (Public) 8. Would you take the energy efficiency label into account if you currently want to buy a new appliance for your home? Why? (Public) 9. Would you buy a new appliance for your home with a higher or lower energy efficiency level than the previous one? Why? (Public) 10. Do you think the RENOVE plan for household appliances influences purchasing decision-making by consumers? If so, how? (Experts) Energy efficiency and energy consumption 1. What do you/consumers/customers understand by energy efficiency? With what concepts do you/they relate energy efficiency? (Public, Experts, Retailers) 2. What do you think is the general profile of the buyer of a high energy-efficiency appliance? (Experts, Retailers) 3. Do you/consumers monitor the energy consumption of appliances in the home? If so, how (by what methods)? (Public, Experts) 4. What do you think is more effective for promoting energy savings: intervening in the purchase decision and/or intervening in energy use? Why? (Experts) Energy efficiency label for appliances 1. How do you/consumers/customers obtain energy efficiency-related information on an appliance when buying it? (Public, Experts, Retailers) 2. Are you/consumers/customers familiar with the energy efficiency label for appliances? (Public, Experts, Retailers) 3. Are you/consumers familiar with the readjusted energy efficiency label for appliances in use since March 2021? What do you/consumers think about it (compared to the previous one)? (Public, Retailers) 4. What do you think about the readjusted energy efficiency label for appliances in use from March 2021 (compared to the previous one)? (Experts) 5. Was the EE label helpful in your/consumers’/customers’ decision-making concerning the purchase of a washing machine/dishwasher/fridge? Why? (Public, Experts, Retailers) 6. To what do you think consumers mainly pay attention on the energy efficiency label for appliances? Why? (Experts) 7. Do you think consumers understand all the information given on the energy efficiency label for appliances? Why? (Experts) 8. Do customers usually ask you for additional information (or clarifications) regarding any of the concepts or symbols that appear on the energy efficiency label for appliances? Which ones? (Retailers) 9. Do you/consumers/customers trust the information on the label? Why? (Public, Experts, Retailers) Potential changes 1. Do you think there is room for improvement in the EE label? What? How? Why? (Public, Experts, Retailers) Energies 2022,15, 4272 21 of 25 2. Do you think it would be useful for you/consumers/customers to have visible monetary information on the energy consumption of the appliance (in euros instead of kWh) when buying? Why? (Public, Experts, Retailers) 3. In what form would it be most useful for you/consumers/customers to have this monetary information on the energy consumption of the appliance: as cost (in euros) or as savings (in euros)? Why? (Public, Experts, Retailers) 4. In what unit would it be most useful for you/consumers/customers to have this monetary information (energy cost or savings): per year, per month, per use, over the useful lifetime of the appliance or others? Why? (Public, Experts, Retailers) 5. Do you think there is any other way to inform about the energy consumption and efficiency of appliances apart from the current energy efficiency label (retailers, stands, apps, real-time information, etc.)? Which one would you prefer? Why? (Public, Experts, Retailers) The role of sales staff (Retailers) 1. Are you up to date on energy efficiency-related issues for household appliances? Are you familiar with the information and technical characteristics of appliances as regards energy efficiency? 2. Do customers ask you for information/explanations about the energy efficiency of the appliance when purchasing? What kind of information do they usually ask you for? 3. What form of providing information on energy efficiency do you think has the most weight in the purchasing decision-making of a new appliance? Why? 4. Does the RENOVE plan for appliances have an impact on your establishment’s sales? How/in what way? Why? 5. Is the possible impact of the RENOVE plan on sales usually felt only while the plan is ongoing or also before and/or afterwards? Why? 6. Does the RENOVE plan for household appliances usually affect the stock of household appliances offered at your establishment? How/in what way? Appendix C. Analysis of Interviews Table A4. Top three attributes mentioned per product category and group interviewed. Washing Machines Fridges Dishwashers Public 1 Technical attributes (ease of use, short duration programmes, rpm) 2 Capacity 3 Ease of use 1 Capacity 2 EE 3 Colour 1 Capacity 2 EE 3 Brand Retailers 1 Price 2 rpm/Brand 3 EE 1 Dimensions 2 Price/Technical attributes (distribution of drawers and No-frost option) 3 Brand 1 Price 2 Brand 3 Capacity Experts 1 Price 2 Brand 3 EE 1 Price 2 Brand 3 EE 1 Price 2 Brand 3 EE Source: Own work based on interview analysis. Notes: (a) The members of the public did not mention the price in their list as they seem to consider it not as an attribute but as a budget constraint. (b) When two attributes are presented in the same rank order (by a /) it is because they were mentioned the same number of times by participants. Energies 2022,15, 4272 22 of 25 Table A5. Units for measuring energy cost and energy savings mentioned by participants in all three types of interviews (public, retailers and experts). Cost Savings Per Year Per Month Per Useful Life Per Uses Combination Per Year Per Month Per Useful Life Per Uses Combination Public 2 1 1 1 1 (per use/s for washing machines and dishwashers + per month for fridges) 1 2 1 (per use/s for washing machines and dishwashers + per month for fridges) Retailers 1 (per use/s for washing machines and dishwashers + per useful life for fridges) 311 1 (per use/s for washing machines and dishwashers + per month for fridges) 1 (per use/s for washing machines and dishwashers + per year for fridges) Experts 4 1 1 (per use/s for washing machines and dishwashers + per month for fridges) 1 (per useful life + per use for all) 2 1 3 TOTAL 6 1 2 4 6 1 4 3 3 Source: Own work based on interview analysis. Energies 2022,15, 4272 23 of 25 References 1. Gerarden, T.D.; Newell, R.G.; Stavins, R.N. Assessing the Energy-Efficiency Gap. J. Econ. Lit. 2017,55, 1486–1525. [CrossRef] 2. Jaffe, A.; Newell, R.; Stavins, R. Economics of Energy Efficiency. Encycl. Energy 2004,2, 79–90. 3. Linares, P.; Labandeira, X. Energy Efficiency: Economics and Policy. J. Econ. Surv. 2010,24, 573–592. [CrossRef] 4. Ramos, A.; Gago, A.; Labandeira, X.; Linares, P. The Role of Information for Energy Efficiency in the Residential Sector. Energy Econ. 2015,52, S17–S29. [CrossRef] 5. Solà, M.d.M.; de Ayala, A.; Galarraga, I.; Escapa, M. Promoting Energy Efficiency at Household Level: A Literature Review. Energy Effic. 2020,14, 6. [CrossRef] 6. Markandya, A.; Labandeira, X.; Ramos, A. Policy Instruments to Foster Energy Efficiency. In Green Energy and Efficiency; Green Energy and Technology; Springer: Cham, Switzerland, 2015; pp. 93–110, ISBN 978-3-319-03631-1. 7. IDAE. Consumo por Usos del Sector Residencial; IDEA: Madrid, Spain, 2021. 8. Waechter, S.; Sütterlin, B.; Siegrist, M. Desired and Undesired Effects of Energy Labels—An Eye-Tracking Study. PLoS ONE 2015 , 10, e0134132. [CrossRef] 9. Egan, C.; Waide, P. A Multi-Country Comparative Evaluation of Labelling Research. Summer Study Proc. Eur. Counc. Energy Effic. Econ. 2005,30, 811–822. 10. Waechter, S.; Sütterlin, B.; Borghoff, J.; Siegrist, M. Letters, Signs, and Colors: How the Display of Energy-Efficiency Information Influences Consumer Assessments of Products. Energy Res. Soc. Sci. 2016,15, 86–95. [CrossRef] 11. Heinzle, S.L.; Wüstenhagen, R. Dynamic Adjustment of Eco-Labeling Schemes and Consumer Choice—The Revision of the EU Energy Label as a Missed Opportunity? Bus. Strat. Environ. 2012,21, 60–70. [CrossRef] 12. London Economics; Ipsos. Study on the Impact of the Energy Label—And Potential Changes to It—On Consumer Understanding and on Purchase Decisions; Final Report Prepared for DG ENER/European Commission; London Economics: London, UK, 2014. 13. Laki´c, E.; Carroll, J.; Gubina, A.F. The Role of Monetary Information in Energy Performance Certificates: A Slovenian Experiment. Energy Effic. 2021,14, 79. [CrossRef] 14. Solà, M.d.M.; de Ayala, A.; Galarraga, I. The Effect of Providing Monetary Information on Energy Savings for Household Appliances: A Field Trial in Spain. J. Consum. Policy 2021,44, 272–310. [CrossRef] 15. Stadelmann, M.; Schubert, R. How Do Different Designs of Energy Labels Influence Purchases of Household Appliances? A Field Study in Switzerland. Ecol. Econ. 2018,144, 112–123. [CrossRef] 16. de Ayala, A.; Foudi, S.; Solà, M.d.M.; López-Bernabé, E.; Galarraga, I. Consumers’ Preferences Regarding Energy Efficiency: A Qualitative Analysis Based on the Household and Services Sectors in Spain. Energy Effic. 2020,14, 3. [CrossRef] 17. Waide, P.; Watson, R.; Attali, S.; Eide, A.; Krivosik, J.; Schiellerup, P. The New Energy Label: Assessing Consumer Comprehension and Effectiveness as a Market Tranformation Tool. In Proceedings of the ECEEE Summer Study Proceedings, Toulon/Hyères, France, 3–8 June 2013. 18. Kallbekken, S.; Sælen, H.; Hermansen, E.A.T. Bridging the Energy Efficiency Gap: A Field Experiment on Lifetime Energy Costs and Household Appliances. J. Consum. Policy 2013,36, 1–16. [CrossRef] 19. Skourtos, M.; Damigos, D.; Tourkolias, C.; Kontogianni, A. Efficient Energy Labelling: The Impact of Information Content and Style on Product Choice. Energy Effic. 2021,14, 58. [CrossRef] 20. Asensio, O.I.; Delmas, M.A. The Dynamics of Behavior Change: Evidence from Energy Conservation. J. Econ. Behav. Organ. 2016 , 126 Pt A, 196–212. [CrossRef] 21. Blasch, J.E.; Filippini, M.; Kumar, N.; Martinez-Cruz, A.L. Boosting the Choice of Energy-Efficient Home Appliances: The Effectiveness of Two Types of Decision Support. Appl. Econ. 2022,54, 3598–3620. [CrossRef] 22. d’Adda, G.; Gao, Y.; Tavoni, M. A Randomized Trial of Energy Cost Information Provision alongside Energy-Efficiency Classes for Refrigerator Purchases. Nat. Energy 2022,7, 360–368. [CrossRef] 23. Bavaresco, M.V.; D’Oca, S.; Ghisi, E.; Lamberts, R. Methods Used in Social Sciences That Suit Energy Research: A Literature Review on Qualitative Methods to Assess the Human Dimension of Energy Use in Buildings. Energy Build. 2020 ,209, 109702. [CrossRef] 24. Galarraga, I.; González-Eguino, M.; Markandya, A. Willingness to Pay and Price Elasticities of Demand for Energy-Efficient Appliances: Combining the Hedonic Approach and Demand Systems. Energy Econ. 2011,33, S66–S74. [CrossRef] 25. Galarraga, I.; Heres, D.R.; Gonzalez-Eguino, M. Price Premium for High-Efficiency Refrigerators and Calculation of PriceElasticities for Close-Substitutes: A Methodology Using Hedonic Pricing and Demand Systems. J. Clean. Prod. 2011 ,19, 2075–2081. [CrossRef] 26. Galarraga, I.; Lucas, J.; González-Eguino, M. Evaluación económica del etiquetado de eficiencia energética: El caso de las lavadoras en España. Pap. De Econ. Española 2012,134, 211–221. 27. Sammer, K.; Wüstenhagen, R. The Influence of Eco-Labelling on Consumer Behaviour—Results of a Discrete Choice Analysis for Washing Machines. Bus. Strat. Environ. 2006,15, 185–199. [CrossRef] 28. Shen, J.; Saijo, T. Does an Energy Efficiency Label Alter Consumers’ Purchasing Decisions? A Latent Class Approach Based on a Stated Choice Experiment in Shanghai. J. Environ. Manag. 2009,90, 3561–3573. [CrossRef] [PubMed] 29. Zhang, Y.; Li, J.; Tao, W. Does Energy Efficiency Affect Appliance Prices? Empirical Analysis of Air Conditioners in China Based on Propensity Score Matching. Energy Econ. 2021,101, 105435. [CrossRef] Energies 2022,15, 4272 24 of 25 30. Zha, D.; Yang, G.; Wang, W.; Wang, Q.; Zhou, D. Appliance Energy Labels and Consumer Heterogeneity: A Latent Class Approach Based on a Discrete Choice Experiment in China. Energy Econ. 2020,90, 104839. [CrossRef] 31. Andor, M.A.; Gerster, A.; Götte, L. How Effective Is the European Union Energy Label? Evidence from a Real-Stakes Experiment. Environ. Res. Lett. 2019,14, 044001. [CrossRef] 32. Andor, M.A.; Gerster, A.; Sommer, S. Consumer Inattention, Heuristic Thinking and the Role of Energy Labels. EJ 2020 ,41, 83–122. [CrossRef] 33. Houde, S. How Consumers Respond to Environmental Certification and the Value of Energy Information; Working Paper Series; National Bureau of Economic Research: Cambridge, MA, USA, 2014. 34. Li, X.; Clark, C.D.; Jensen, K.L.; Yen, S.T. The Effect of Mail-in Utility Rebates on Willingness-to-Pay for ENERGY STAR Certified Refrigerators. Environ. Resour. Econ. 2016,63, 1–23. [CrossRef] 35. Ward, D.O.; Clark, C.D.; Jensen, K.L.; Yen, S.T.; Russell, C.S. Factors Influencing Willingness-to-Pay for the ENERGY STAR ® Label. Energy Policy 2011,39, 1450–1458. [CrossRef] 36. Schleich, J.; Durand, A.; Brugger, H. How Effective Are EU Minimum Energy Performance Standards and Energy Labels for Cold Appliances? Energy Policy 2021,149, 112069. [CrossRef] 37. Waide, W.; Watson, R.; Attali, S.; Eide, A.; Schiellerup, P.; Krivosik, J. Energy Labelling: The New European Energy Label: Assessing Consumer Comprehension and Effectiveness as a Market Transformation Tool|Copenhagen Centre on Energy Efficiency—Knowledge Management System; Copenhagen Centre on Energy Efficiency: Copenhagen, Denmark, 2013. 38. Deutsch, M. Life Cycle Cost Disclosure, Consumer Behavior, and Business Implications. J. Ind. Ecol. 2010 ,14, 103–120. [CrossRef] 39. Bull, J. Loads of Green Washing—Can Behavioural Economics Increase Willingness-to-Pay for Efficient Washing Machines in the UK? Energy Policy 2012,50, 242–252. [CrossRef] 40. Heinzle, S.L. Disclosure of Energy Operating Cost Information: A Silver Bullet for Overcoming the Energy-Efficiency Gap? J. Consum. Policy 2012,35, 43–64. [CrossRef] 41. Solà, M.d.M.; Escapa, M.; Galarraga, I. Effectiveness of Monetary Information in Promoting the Purchase of Energy-Efficient Appliances: Evidence from a Field Experiment at a Major Retailer in Spain; BC3 Working Paper Series 2021-03; Basque Centre for Climate Change (BC3): Bilbao, Spain, 2021. 42. Allcott, H.; Sweeney, R.L. The Role of Sales Agents in Information Disclosure: Evidence from a Field Experiment. Manag. Sci. 2016,63, 21–39. [CrossRef] 43. Carroll, J.; Denny, E.; Lyons, S. The Effects of Energy Cost Labelling on Appliance Purchasing Decisions: Trial Results from Ireland. J. Consum. Policy 2016,39, 23–40. [CrossRef] 44. Cook, K.E. In-Depth Interview. In Sage Encyclopedia of Qualitative Methods; SAGE: Thousand Oaks, CA, USA, 2008; pp. 422–423. 45. Malhotra, N.; Nunan, D.; Birks, D. Marketing Research: An Applied Approach; Pearson Education Limited: London, UK, 2017; ISBN 978-1-292-10312-9. 46. Starr, M.A. Qualitative and Mixed-Methods Research in Economics: Surprising Growth, Promising Future. J. Econ. Surv. 2014 , 28, 238–264. [CrossRef] 47. Sty´sko-Kunkowska, M. Interviews as a Qualitative Research Method in Management and Economics Sciences; Warsaw School of Economics: Warsaw, Poland, 2014. 48. Newing, H. Conducting Research in Conservation: Social Science Methods and Practice; Routledge: London, UK, 2010. 49. Kallbekken, S.; Aasen, M. The Demand for Earmarking: Results from a Focus Group Study. Ecol. Econ. 2010 ,69, 2183–2190. [CrossRef] 50. Silvestri, A.; Foudi, S.; Galarraga, I.; Ansuategi, A. The Contribution of Carsharing to Low Carbon Mobility: Complementarity and Substitution with Other Modes. Res. Transp. Econ. 2021,85, 100968. [CrossRef] 51. Erlingsson, C.; Brysiewicz, P. A Hands-on Guide to Doing Content Analysis. Afr. J. Emerg. Med. 2017,7, 93–99. [CrossRef] 52. Elo, S.; Kyngäs, H. The Qualitative Content Analysis Process. J. Adv. Nurs. 2008,62, 107–115. [CrossRef] [PubMed] 53. Hsieh, H.-F.; Shannon, S.E. Three Approaches to Qualitative Content Analysis. Qual. Health Res. 2005 ,15, 1277–1288. [CrossRef] [PubMed] 54. Lucas, J.; Galarraga, I. Green Energy Labelling. In Green Energy and Efficiency; Green Energy and Technology; Springer: Cham, Switzerland, 2015; pp. 133–164, ISBN 978-3-319-03631-1. 55. Jain, M.; Rao, A.B.; Patwardhan, A. Appliance Labeling and Consumer Heterogeneity: A Discrete Choice Experiment in India. Appl. Energy 2018,226, 213–224. [CrossRef] 56. Waechter, S.; Sütterlin, B.; Siegrist, M. The Misleading Effect of Energy Efficiency Information on Perceived Energy Friendliness of Electric Goods. J. Clean. Prod. 2015,93, 193–202. [CrossRef] 57. Dieu-Hang, T.; Grafton, R.Q.; Martínez-Espiñeira, R.; Garcia-Valiñas, M. Household Adoption of Energy and Water-Efficient Appliances: An Analysis of Attitudes, Labelling and Complementary Green Behaviours in Selected OECD Countries. J Environ. Manag. 2017,197, 140–150. [CrossRef] [PubMed] 58. Martinez-Espiñeira, G.V.; García-Valiñas, A.M.; Nauges, C. Households’ pro-Environmental Habits and Investments in Water and Energy Consumption: Determinants and Relationships. J. Environ. Manag. 2014,133, 174–183. [CrossRef] [PubMed] 59. Millock, K.; Nauges, C. Household Adoption of Water-Efficient Equipment: The Role of Socio-Economic Factors, Environmental Attitudes and Policy. Environ. Resour. Econ 2010,46, 539–565. [CrossRef] Energies 2022,15, 4272 25 of 25 60. Trotta, G. Factors Affecting Energy-Saving Behaviours and Energy Efficiency Investments in British Households. Energy Policy 2018,114, 529–539. [CrossRef] 61. Abrahamse, W.; Steg, L.; Vlek, C.; Rothengatter, T. A Review of Intervention Studies Aimed at Household Energy Conservation. J. Environ. Psychol. 2005,25, 273–291. [CrossRef] 62. Cattaneo, C. Internal and External Barriers to Energy Efficiency: Which Role for Policy Interventions? Energy Effic. 2019 , 12, 1293–1311. [CrossRef] 63. Min, J.; Azevedo, I.L.; Michalek, J.; de Bruin, W.B. Labeling Energy Cost on Light Bulbs Lowers Implicit Discount Rates. Ecol. Econ. 2014,97, 42–50. [CrossRef] 64. Gram-Hanssen, K.; Bartiaux, F.; Michael Jensen, O.; Cantaert, M. Do Homeowners Use Energy Labels? A Comparison between Denmark and Belgium. Energy Policy 2007,35, 2879–2888. [CrossRef] 65. Mutumbi, U.; Thondhlana, G.; Ruwanza, S. Co-Designed Interventions Yield Significant Electricity Savings among Low-Income Households in Makhanda South Africa. Energies 2022,15, 2320. [CrossRef] 66. Galarraga, I.; Abadie, L.M.; Ansuategi, A. Efficiency, Effectiveness and Implementation Feasibility of Energy Efficiency Rebates: The “Renove” Plan in Spain. Energy Econ. 2013,40, S98–S107. [CrossRef] 67. Datta, S.; Gulati, S. Utility Rebates for ENERGY STAR Appliances: Are They Effective? J. Environ. Econ. Manag. 2014 ,68, 480–506. [CrossRef] 68. Train, K.E.; Atherton, T. Rebates, Loans, and Customers’ Choice of Appliance Efficiency Level: Combining Statedand RevealedPreference Data. Energy J. 1995,16, 55–69. [CrossRef] 69. Allcott, H.; Knittel, C. Are Consumers Poorly Informed about Fuel Economy? Evidence from Two Experiments. Am. Econ. J. Econ. Policy 2019,11, 1–37. [CrossRef]