Comparative Analysis of Global Consumer Behaviour in the Context of Different Manual Dishwashing Methods

International Journal of Consumer Studies ISSN 1470-6423

Comparative analysis of global consumer behaviour in the

context of different manual dishwashing methodsijcs_1051 1..13 Petra Berkholz, Verena Kobersky and Rainer Stamminger

Bonn University, Institute of Agricultural Engineering, Household and Appliance Technology Section, Bonn, Germany

Keywords Abstract Consumer behaviour, resource consumption, manual washing up, automatic dishwashing, This laboratory study presents an overview of the global manual dishwashing behaviour. household appliances, household technology. The focus of the investigation was to analyse individual attitudes towards manual dishwashing and to determine the amount of water and energy used, as well as the cleaning Correspondence performance achieved. Additionally, manual dishwashing was compared with automatic Rainer Stamminger, Institute of Agricultural dishwashers. Two hundred eighty-nine participants from 29 countries took part in this Engineering, Household and Appliance investigation. Each consumer had to wash up a complete soiled dishwasher load consisting Technology Section, Nussallee 5, 53115 of 12 place settings based on both international and local performance test standards for Bonn, Germany. automatic dishwashers. Country-specific aspects such as tableware, food residues or E-mail: [email protected] washing up equipment were considered. In order to analyse individual consumer’s behaviour, each participant was recorded on video and had to fill out a questionnaire. The doi: 10.1111/j.1470-6431.2011.01051.x resource consumption for washing up dishes was measured during the tests. At the end of each trial, the cleaning result of the washed up tableware was assessed. To compare manual with automatic dishwashing, country-specific dishwasher models were tested in parallel with three different programmes with the same soiled dish samples. The study provides comprehensive data about the average resource consumption for manual dishwashing for a specific load for each country. The average water consumption per country reached 34.7 l up to 160.1 l, and individual values ranged from 18.3 l to 472.8 l. The lowest used average heat quantity accounted for 0.9 kWh per country, while the highest amount was five times higher. The cleaning results did not differ much between the countries: the average test results were between 2.2 and 2.8 on a scale between 0 and 5. The automatic dishwasher tests showed differences between both the machines and the programmes. All machines achieved lower water consumption values than the average consumers with about 9.6 l to 26.7 l of water on average. The energy consumption ranged from 0.5 kWh on average up to 2.0 kWh. The cleaning results of the dishwasher tests varied highly ranging from 1.1 in a quick programme to 4.4 in an intensive programme. The study comes to the conclusion that automatic dishwashing is more superior as compared with manual dishwashing in terms of performance and resource consumption under the tested conditions. Furthermore, it points out that washing up dishes under running tap water is the most water-consuming manual dishwashing method of all investigated ones. A high lack of knowledge about the benefits of automatic dishwashing compared with manual dishwashing can still be identified among consumers.

Introduction discussions was a definition of the term sustainable development, summarized 1987 in ‘Our Common Future’, better known as the Sustainability and sustainable development are both terms that Brundtland Report (United Nations, 1987). Two main definitions have been given various meanings by politicians, socialists, econo- of sustainability are named within this document: mists and ecologists in the past decades. Early discussions about 1 ‘Sustainable development seeks to meet the needs and aspira- the concept of sustainable development were phrased back in the tions of the present without compromising the ability to meet those 1960s during a UNESCO Conference (International Institute for of the future’ (United Nations, 1987, p. 51). Sustainable Development, 2002). Over the years, publications, 2 ‘In essence, sustainable development is a process of change in research findings and global conferences made up the concept of which the exploitation of resources, the direction of investments, sustainability as the focus of their interest. An outcome of all these the orientation of technological development, and institutional

International Journal of Consumer Studies 1 © 2011 Blackwell Publishing Ltd Analysis of global manual dishwashing methods P. Berkholz et al. change are all in harmony and enhance both current and future European investigation was only based on a limited number of potential to meet human needs and aspirations’ (United Nations, participants, Berkholz et al. (2010) replicated the study by choos- 1987, p. 57). ing a larger and fully representative sample of UK participants. In But in the background of the increasing effect of climate change addition, each study compared the hand wash results with those of and global warming, all political efforts that have been made until an automatic dishwasher tested under the same conditions. Both today do not seem to be enough. At present, the decrease of studies were conducted in a laboratory under consumer relevant non-renewable resources makes it necessary to rethink about test conditions. In contrast to that, Richter (2010) investigated 200 energy and water demand behaviour not only in the domestic households in four European countries to identify the washing up sector. Both the world population and also the demand for behaviour under real-live conditions. The analyses of Vivian et al. resources are continually growing (United Nations, 2005). (2011) focused on the energy and the associated carbon dioxide Already today, one of the largest energy users in the European equivalent emission from both washing up dishes by hand and Union is the domestic household sector due to its increasing using an automatic dishwasher. Additionally, the consumer behav- demand for heating and appliances (European Environment iour was also taken into account in the assessment. All studies Agency, 2005). Future prospects expect, that especially in the came to the conclusion that on average, a dishwasher needs con- developed countries, consumers will be even more dependent on siderably less water and energy and reaches on average better appliances due to lifestyle changes and the increasing desire for cleaning results when used efficiently compared with hand wash. technology and comfort. Furthermore, a trend towards smaller Because these studies were only limited to some European coun- household sizes can be identified. Simultaneously, the number of tries, the need of future investigations was given to include also single households is increasing as well (European Environment habits and attitudes of consumers in non-European countries. Agency, 2005; European Commission, 2008). Future prospects indicate for Europe that the household energy demand will rise by 12% until 2030 (European Commission, 2008). Due to these Research question developments, the household appliance industry – especially for Published research have already investigated washing up habits those of white goods – has made a step forward to encourage both under laboratory and real-life conditions. But their focus was consumers to act in a more sustainable way by implementing limited to consumers living in Europe, where living conditions do energy labels. Less efficient appliances disappeared from the not differ that much between countries. In order to get a deeper market, because consumers demanded machines with higher effi- insight into washing up habits and resource consumption for ciency classes (Presutto et al., 2007). manual dishwashing outside the European Union, the main aim of When looking at the market saturation of household appliances the present investigation should be to broaden the existing Euro- on a global base, inhomogeneous distribution can be identified even pean studies by including also non-European countries into the for the higher developed countries. Taking dishwashing as an focus of research. Thereby, a better understanding of worldwide example, automatic dishwashers show an increasing market manual dishwashing practices and consumer insights are given share in Germany and the United States during the last decades which could be used to develop recommendations for best prac- (US Energy Information Administration, 2001; Zentralverband tices in the future. Participants of several representative states Elektrotechnik- und Elektronikindustrie e.V., 2011), because the from all continents were chosen to take part in the study. Tests usage of this household appliance is common in both countries for were performed in Germany and abroad. The analysis of consumer decades. But there are still countries with a low market saturation of behaviour should be researched, on the one hand, by measuring automatic dishwashers, where these appliances almost have a status energy and water consumption data as well as the cleaning result. of luxury goods (Grady, 2004). Different lifestyles, traditions and On the other hand, washing up techniques and habits should be needs, but also high purchasing costs, can be assumed as reasons for identified within a non-participant observation and a question- this market development. It indicates that in these countries, a lot of naire. Based on this, it should be researched if similar results like different household tasks are still done without the help of certain in the investigation of Stamminger et al. (2007) and Berkholz appliances, for example, dishwashing. But while household appli- et al. (2010) could be found. Furthermore, it should be discovered ances have to fulfil specific standards for energy and performance if the consumers really behave in the same way as they answered tests before being launched in the market, there are only limited data in the questionnaire. available about how many resources are used for various home tasks To compare manual with automatic dishwashing, dishwasher that are still done by hand. Low knowledge about new technologies models that are characteristic of each participating country should and a low awareness about the resource consumption of daily be tested in parallel with the same dish samples as for the specific routine procedures among consumers are still present. Therefore, test countries. additional research is needed to disclose this gap, for example, by providing well-founded data that can be used as a basis for consumer education. Materials and methods On the topic of dishwashing, several investigations tried to disclose both resource consumptions and consumer habits on a Consumer study European base (Stamminger et al., 2007; Berkholz et al., 2010; Richter, 2010; Vivian et al., 2011). Stamminger et al. (2007) gave Overall, 289 consumers took part in this investigation. The major- a first detailed analysis of both manual dishwashing habits and ity of the tests were conducted in the laboratories of Bonn Uni- data measurements about the energy and water consumption as versity. Furthermore, additional consumer tests were also well as the cleanliness of the washed up tableware. Because the performed abroad in three different countries. All participants

Table 1 Consumer panel: country of origin and no. of consumers per test country

No. of Among these Region Abbr. Nationality/ethnicity participants tested abroad Used dishwasher test standard

Australia/ AU/NZ Australian 17 – AS/NZS 2007.1 (Joint Standards Australia/ New Zealand New Zealand 3 – Standards New Zealand Committee EL-015, 2007)/IEC 60436:2004+A1:2009 (E) (International Electrotechnical Commission, 2009) Europe DE German 20 – IEC 60436:2004+A1:2009 (E) HU Hungarian 20 – IEC 60436:2004+A1:2009 (E) RU Belorussian 1 – Georgian 4 – Russian 10 – Ukrainian 4 – Uzbekistani 1 – Asia CN Chinese 30 10 IEC 60436:2004+A1:2009 (E) JP Japanese 20 – JEMA HD-084 (Japan Electrical Manufacturers’ Association, 2008)/IEC 60436:2004+A1:2009 (E) KR Korean 20 – MKE’s notiﬁcation 2008–99 (Ministry of Knowledge Economy Korea Energy Management Corporation, 2008)/IEC 60436:2004+A1:2009 (E) Latin America LATAM Argentine 1 – IEC 60436:2004+A1:2009 (E) Brazilian 5 – Colombian 9 – Mexican 4 – Peruvian 1 – Middle East ME Egyptian 2 – IEC 60436:2004+A1:2009 (E) Iranian 4 – Jordanian 3 – Omanis 1 – Pakistani 2 – Palestine 4 – Syrian 2 – Yemeni 2 – Southern Africa ZA Malagasy 1 – IEC 60436:2004+A1:2009 (E) Mosotho 1 1 South African 17 17 North America US US American Asian 2 1 ANSI/AHAM 2005-DW-1 (Association of Black/African American 7 7 Home Appliance Manufacturers, 2005)/ Hispanic/Latino 4 3 IEC 60436:2004+A1:2009 (E) Two or more races 4 4 White 63 45

were citizens from one of the seven investigated regions that were South Africa and the United States, participants were recruited by selected in order to represent all continents (Table 1). telephone from user panels by simple random sampling. The user Consumers had to match specific criteria in order to take part in panels were generally used for consumer research at Reckitt this research: none of them were permitted to have lived more than Benckiser Ltd. and BSH Home Appliances Ltd. 3 years in Germany. This was to avoid the participants adopting The test setup and preparation for the consumer study per- German habits. Additionally, participants must have experience in formed in Germany and abroad were identical. The conduction of manual dishwashing and had to be older than 18 years. all tests was done by a scientific research group of Bonn Univer- For the consumer tests performed in Germany, the recruitment sity. Tests were performed under uniform conditions similar to the of the panel was done in two cities named Bonn and Cologne. international test standard IEC 60436:2004+A1:2009 (E) – Elec- Trialists were recruited through notes posted on the campus in tric dishwashers for household use – methods for measuring the both German cities, but also using web-based social networks and performance (International Electrotechnical Commission, 2009). foreign country organizations. The same recruitment method was In total, 12 place settings were soiled with specific food for each also used for the tests done in China. For the investigations in consumer test. Six place settings were prepared similar to the IEC

Table 2 Test standards and soiling agents Table 3 Evaluation of the cleaning performance according to EN 50242:2008 (Europäisches Komitee für Elektrotechnische Normung, Test standard Soiling agents 2008) AS/NZS 2007.1 Black tea, egg yolk, infant cereal, Number of small Total soiled area margarine, spinach, tomato juice Score dot-shaped particles (n) in mm2 (A) JEMA HD-084 Curry-rice, cutlet with sauce, egg sunny-side up, green tea, milk, 5 n = 0A= 0 miso soup, rice, tomato juice 40< n Յ 40< A Յ 4 MKE’s notification 2008–99 Cayenne pepper, coffee, egg yolk, 34< n Յ 10 0 < A Յ 4 kimchi, margarine, milk 210< n 4 < A Յ 50 ANSI/AHAM 2005-DW-1 Coffee, coffee ground, egg yolk, 1 Not applicable 50 < A Յ 200 mashed potatoes, minced meat, 0 Not applicable 200 < A porridge, preserves, sweet corn, tomato juice IEC 60436:2004+A1:2009 (E) Black tea, egg yolk, milk, minced meat, porridge, spinach • The cold and hot water consumptions were measured using calibrated in-line flow meters. • The cold and hot water temperatures were taken using 60436:2004+A1:2009 (E) (International Electrotechnical Com- thermocouples. mission, 2009), whereas the other six place settings were prepared The energy and the heat quantity used to heat up the water were according to the specific electrical dishwasher test standard of the calculated using the following equation: country the participants came from. The tableware consisted of =××−()()+××−()° (1) different kinds of glasses, cups, saucers, various-sized plates and Qhot V hot cT hot T cold V hot cT cold 15C / 3600 bowls, serving dishes, cutlery and chopsticks. Each test standard with: specifies in detail the amount and application method of the soiling Qhot = heat quantity of warm water in kWh; agents on the tableware. An overview of the various soils that were Vhot = volume of warm water in l; used within this research is given in Table 2. Thot = temperature of warm water in °C; After the preparation, all dishes were dried in air at a room Tcold = temperature of cold water in °C; and temperature of 23 Ϯ 2°C and relative humidity of 55 Ϯ 5% for 2 h c = specific heat capacity of water: 4.19 kJ/kgK. (International Electrotechnical Commission, 2009). The calculated heat quantity was corrected according to the After the drying phase, the twelve place settings were presented temperature of the cold water so that the adjusted value was to the consumer. Each participant was then asked to wash up all the equivalent to the amount of heat quantity that would have been dishes by hand in the way he or she was used to from his or her used if the incoming cold water had been a temperature of 15°C. own native country. No limitation was made to the washing up All participants were left alone during the experiment in order practice except that all participants had to dry all crockery with to keep factors that might have an influencing impact on the linen tea towels. Each participant could choose between five behaviour as small as possible. Each trialist was recorded on different country-specific liquid hand dishwashing detergents video while washing up. The videos were used to analyse the including both brands and private labels. Different dishwashing up individual habits. Therefore, all dishwashing steps of each con- tools could be used during the tests such as gloves, a brush, dish sumer were counted. One dishwashing step is thereby defined as cloth, sponge cloth, scrub sponge, spiral scourer and differently the manual washing up process of a composition of equal dishes, sized draining racks. The kitchen workplace consisted of a double e.g. glasses, cups, saucers, etc. In a next step, it was analysed sink construction and a drainer at the left side of the double sink. how many of all the dishwashing steps were done (1) under Each sink had a maximum capacity of approx. 14 l. They both running tap water; (2) in a water-filled sink; or (3) by combining could be filled with water using a flexible mixture tab. A both methods. At the end of each test, the cleanliness of the continuous-flow heater provided unlimited hot water up to a washed up tableware was assessed visually according to EN maximum temperature of 60°C. This setting was chosen because it 50242:2008 (Europäisches Komitee für Elektrotechnische is the recommended temperature at which the growth of Legionel- Normung, 2008) (Table 3). lae is avoided (Deutscher Verein des Gas- und Wasserfaches, 2004). No special treatment of the water utilized in the tests was Dishwasher study carried out. The local town water was taken. The water hardness level for the tests conducted in Bonn, Germany was 1.1 mmol/l on In parallel to the consumer study, dishwasher tests were also average. For the consumer tests performed abroad, the following performed in the laboratories of Bonn University. In total, six local water hardness levels were measured: country-specific dishwasher models were tested (Table 4) for • Johannesburg, South Africa (ZA): 1.4 mmol/l; cleaning performance, energy and water consumption. For China, • Beijing, China (CN): 3.7 mmol/l; Germany, Hungary, Russia and the countries belonging to the • Montvale, NJ, USA (US): 1.5–2.5 mmol/l; Middle East (ME) and Southern Africa, only one appliance was • Denver, CO, USA (US): 0.7–1.5 mmol/l; tested. This specific model was available on each of these different • Houston, TX, USA (US): 0.7–1.5 mmol/l. markets. The following data were measured with a calibrated data Each country-specific machine was loaded with the same logging system that recorded all incoming data every second: amount of dishes according to the consumer tests of certain

Table 4 Dishwasher models under test according to test region and test standard

Abbr. of tested Region dishwasher Brand/model no. Test standard

Australia/New Zealand AU/NZ Bosch/SMI50E25AU AS/NZS 2007.1/IEC 60436:2004+A1:2009 (E) Japan JP National/NP-33S2 JEMA HD-084/IEC 60436:2004+A1:2009 (E) Korea KR Siemens/SN25E230EA MKE’s notiﬁcation 2008–99/IEC 60436:2004+A1:2009 (E) Latin America LATAM Bosch/SMS63M08MX IEC 60436:2004+A1:2009 (E) USA US Bosch/SHE55M05UC ANSI/AHAM 2005-DW-1/IEC 60436:2004+A1:2009 (E) China EU Siemens/SN26M230EU IEC 60436:2004+A1:2009 (E) Germany EU Siemens/SN26M230EU IEC 60436:2004+A1:2009 (E) Hungary EU Siemens/SN26M230EU IEC 60436:2004+A1:2009 (E) Middle East EU Siemens/SN26M230EU IEC 60436:2004+A1:2009 (E) Russia EU Siemens/SN26M230EU IEC 60436:2004+A1:2009 (E) Southern Africa EU Siemens/SN26M230EU IEC 60436:2004+A1:2009 (E)

countries.1 The test preparation of the tableware was equivalent Table 5 Characteristics of the consumer panel (n = 289) to those done for the manual washing up experiment. In order No. % to reflect different consumer habits when using a dishwasher, three different dishwasher programmes were tested in each Individuals per household machine: a quick, normal and intensive cycle. The used automatic 15318 dishwashing detergent was the Reference Detergent Type B (Wfk, 26021 Testgewebe, Krefeld, Germany), and the rinse agent was Formula 36021 III (Wfk) according to IEC 60436:2004+A1:2009 (E) (Interna- 45920 tional Electrotechnical Commission, 2009). No special salt was 53412 added to the machines. Each machine was run with local town 6166 water at a water hardness level of 1.1 mmol/l on average. 752 The following data were recorded every second using a cali- 921 Age brated data logging system: 18–24 109 34 • The total water consumption V was measured using calibrated inl 25–34 96 30 in-line flow meters. 35–44 37 11 • The temperature Tinl of the incoming water was taken using 45–54 40 12 thermocouples. 55–64 6 2 • The energy consumption Emea was measured. Equivalent to the >64 1 >1 consumer study, the used energy was corrected up to a cold water Gender temperature of 15°C using the following equations according to Female 208 72 IEC 60436:2004+A1:2009 (E) (International Electrotechnical Male 81 28 Commission, 2009): () EVcTcorr=××− inl inl 15°C / 3600 (2) with: Results and discussion Ecorr = corrected energy consumption in kWh; Vinl = total water consumption in l; Characteristics of the consumer panel Tinl = temperature of the incoming water in °C; and c = specific heat capacity of water: 4.19 kJ/kgK. A consumer sample of, in total, 289 people took part in the investigation. Participants were all inhabitants of 29 countries which

EEEtotal=+ mea corr (3) were allocated to seven worldwide regions (Table 1). Consumers with: were between 18 to over 64 years old. The majority of participants were younger than 35 years (64%). More than two-thirds of the Etotal = total energy consumption in kWh; and participants were female. Two to three individuals per household Emea = measured energy consumption in kWh. At the end of each programme, the cleaning performance was was the household size that occurred most frequently (Table 5). assessed visually according to EN 50242:2008 (Europäisches Komitee für Elektrotechnische Normung, 2008). Overview on the resource consumption for manual and automatic dishwashing

1The Japanese dishwasher model was only tested with ﬁve place settings Figures 1–3 show the median results of the water consumption, the due to its lower maximum loading capacity. corrected energy and corrected heat quantity consumption and the

Figure 1 Statistical data of the water consumption values in l, user trial and dishwasher tests with median (AU/NZ: Australia/New Zealand, manual dishwashing; DW AU/NZ: Australia/New Zealand, dishwasher; JP: Japan, manual dishwashing; DW JP: Japan, dishwasher; KR: Korea, manual dishwashing; DW KR: Korea, dishwasher; CN: China, manual dishwashing; ME: Middle East, manual dishwashing; ZA: Southern Africa, manual dishwashing; DE: Germany, manual dishwashing; HU: Hungary, manual dishwashing; RU: Russia, manual dishwashing; DW EU: Europe, dishwasher; LATAM: Latin America, manual dishwashing; DW LATAM: Latin America, dishwasher; US: United States, manual dishwashing; DW US: United States, dishwasher).

cleaning results for both the user trial and the automatic dish- identified [rS = 0.76 P (one-tailed) < 0.01]. Therefore, a similar washer tests. distribution of the corrected heat quantity data compared The median values of the consumer trial indicate high differ- with the water consumption can be observed (Fig. 2). The ences between the countries (Fig. 1). The median values range median values range from 0.9 kWh (ZA) to 4.6 kWh (RU). The from 34.7 l (AU/NZ) up to 160.1 l (RU). But also within one country with the largest range of the middle 50% is again country, the taken data show a high variation. Countries within a RU with a difference of 3.8 kWh. The lowest range between small difference between the 75th and the 25th percentile – that the 25th and the 75th percentile was measured for AU/NZ means countries where the majority of consumers wash up in a (D 0.5 kWh). Extreme values were calculated for the corrected more uniform way – can be identified (AU/NZ: D 19.6 l, ZA: D heat quantity as well. Some participants did not use any 28.8 l, DE: D 29.9 l). In contrast to that, 50% of the participants hot water at all for washing up (JP, CN, ZA, US), so that no from Russia needed between 86.4 l and 221.4 l of water to wash heat quantity could be calculated. Those consumers stated that up a similar dish amount. Extreme values were measured as well. they did not use any hot water for washing up dishes at The lowest water consumption was at 18.3 l (AU/NZ), while the home either. Named reasons were either that those consumers highest was up to 26 times higher (US: 472.8 l). do not have any hot water supply at their kitchen sink at The water consumption results in the dishwasher tests showed home or that they live in regions with a very warm climate, lower values for all machines in all programmes compared with which makes it unnecessary to heat up the water. In contrast to the manual washing up tests. The lowest water consumption the lowest calculations, the highest value was almost 15 kWh results for all machines were measured in the quick cycle. The (US). measurements range from 9.6 l [Latin America (LATAM)] up to The average dishwasher results of the corrected energy con- 12.7 l (US). In contrast to that, in the intensive programme, sumption are in general lower than those of the consumers. In between 12.8 l (LATAM) and 26.7 l (US) were used. the quick cycle, measurements range from 0.5 kWh (JP) to In the consumer test, a significant relationship between 0.9 kWh (US), and in the intensive cycle from 1.1 kWh (JP) to the water consumption and the corrected heat quantity can be 2.0 kWh (US). However, in the consumer tests, some countries

Figure 2 Statistical data of the corrected heat quantity consumption values and corrected energy consumption values in kWh, user trial and dishwasher tests with median (AU/NZ: Australia/New Zealand, manual dishwashing; DW AU/NZ: Australia/New Zealand, dishwasher; JP: Japan, manual dishwashing; DW JP: Japan, dishwasher; KR: Korea, manual dishwashing; DW KR: Korea, dishwasher; CN: China, manual dishwashing; ME: Middle East, manual dishwashing; ZA: Southern Africa, manual dishwashing; DE: Germany, manual dishwashing; HU: Hungary, manual dishwashing; RU: Russia, manual dishwashing; DW EU: Europe, dishwasher; LATAM: Latin America, manual dishwashing; DW LATAM: Latin America, dishwasher; US: United States, manual dishwashing; DW US: United States, dishwasher).

still achieved on average lower values (AU/NZ, CN, ZA) due to results are linked to a higher variety of washing up techniques the fact that they used in total less warm water. Reasons for that within one country. On the opposite, the median values of all were either to save water in general (AU/NZ) or because – as countries lay quite close together ranging only from 2.2 mentioned above – some participants were not accustomed to (LATAM) to 3.0 (HU). This could be seen as an indicator for a using a lot of warm water or indeed any warm water at all for similar meaning of cleanliness among all participants. On washing up dishes (CN/ZA). The differences of the resource average, participants washed up until the favoured cleaning level consumption values both between the countries and within one was achieved. country indicate that different washing up methods were used The cleaning results of the dishwasher tests show differences in that effect those high deviations. Similar results were also the performance of the six tested models. The lowest performance observed in the investigations of Stamminger et al. (2007) and of all machines was achieved by the Japanese dishwasher in all Berkholz et al. (2010). programmes. Even the Japanese consumer panel achieved better Having a closer look at the cleaning results (Fig. 3) to average cleaning results than the machine did. Overall, the perfor- compare the middle 50% within the countries, again large mance in all quick cycles is lower compared with the average differences can be assessed. Countries with a relatively low consumer results. In contrast to that, the cleaning scores in the range between the 25th and 75th percentile can be deﬁned normal and intensive cycles are higher or equal (US) to the average (LATAM & JP: D 0.8) as well as countries with a larger range results of the consumers. The best performing models are the EU (CN: D 1.7). Based on this, it can be assumed that consumers in and LATAM dishwashers. Their results range between 2.1 and 2.2 those countries seem to have a more differentiated picture of in the quick programme up to 4.2 (EU) and 4.4 (LATAM) in the cleanliness than others. Possibly, the deviations in the cleaning intensive cycle.

Figure 3 Statistical data of the cleaning indices, user trial and dishwasher tests with median (AU/NZ: Australia/New Zealand, manual dishwashing; DW AU/NZ: Australia/New Zealand, dishwasher; JP: Japan, manual dishwashing; DW JP: Japan, dishwasher; KR: Korea, manual dishwashing; DW KR: Korea, dishwasher; CN: China, manual dishwashing; ME: Middle East, manual dishwashing; ZA: Southern Africa, manual dishwashing; DE: Germany, manual dishwashing; HU: Hungary, manual dishwashing; RU: Russia, manual dishwashing; DW EU: Europe, dishwasher; LATAM: Latin America, manual dishwashing; DW LATAM: Latin America, dishwasher; US: United States, manual dishwashing; DW US: United States, dishwasher).

thought that using a dishwasher results in a higher performance. The attitude of consumers towards The common usage of automatic dishwasher among US consum- dishwashing ers could be seen as one possible reason why US Americans are Thirty-three percent of all participants stated that they had a dish- persuaded of the performance of a dishwasher. Instead, among the washer at home. The main purchase reason for those consumers is Asian countries (KR, JP) where dishwasher usage is not very the time-saving aspect when using a dishwasher (69%). Forty-five common, a clearly low belief in dishwasher cleaning results can be percent responded that they regularly have so many dirty dishes at identified. This is also true for the developing countries in LATAM home that the use of a dishwasher is necessary. The third important and the ME. aspect (36%) is that the cleaning result of dishes washed in a Forty-three percent of dishwasher owners replied that a dish- dishwasher is better compared with hand washed dishes. Less than washer cleans the dishes better than manual dishwashing. Never- one-third of the dishwasher owners answered that they use the theless, 37% still think that manual dishwashing results in a higher machine in order to save water and energy. These findings can also cleanliness. As this is not supported by the dishwasher test results be supported by the studies of Stamminger et al. (2007) and within this study (Fig. 3), the continuously wrong usage of the Berkholz et al. (2010). Also in these investigations, resource appliance and the cleaning detergent might be a reason for this savings were found not to be on top of consumers’ minds when opinion, e.g. incorrect programme choice, improper loading con- purchasing a dishwasher. ditions, damp detergent, etc. In a further question, people had to estimate which one In total, 37% of all participants replied that manual dishwashing of the two dishwashing methods delivers a better cleaning result saves more energy and water than automatic dishwashing. In con- (Fig. 4). Thirty-nine percent of all participants said that manual trast to that, about 33% were of the opinion that automatic dish- dishwashing reaches a better performance while only 25% washing is more economic friendly (Fig. 4). When only looking at answered that an automatic dishwasher cleans better. Only the the group of people who have a dishwasher at home (33%), over majority of Hungarian (HU: 50%) and US Americans (US: 49%) 50% replied that automatic dishwashing saves water and energy

Figure 4 What do you think achieves better results and respectively needs less water and less energy: doing the dishes by hand or using a dishwasher?

compared with manual dishwashing. But still, approximately one- these three countries do between 30 and 70% of all dishwashing third believe that manual dishwashing is more economic friendly. steps under running tap water. Countries like Germany (DE), Southern Africa (ZA) and Australia/New Zealand (AU/NZ) are more in favour of washing up in a water-filled sink because more Consumers’ manual washing up behaviour and than 50% of the consumers washed up less than 30% of all dish- its impact on water consumption washing steps under running tap water. This analysis proves that On the basis of both the questionnaire and the video analysis, three participants of countries that stated doing the dishes previously different washing up methods could be identified: washing up (1) under running tap water finally washed up the dishes with this under running tap water; (2) in a water-filled sink; and (3) in a method in the test. The same findings could be noticed for con- combined way of both under running tap water and in a filled sink sumers washing up in a filled sink or combining both methods. (Figs 5 and 6). A statistical comparison was done in order to analyse whether When looking at the consumer panel in total, the running tap the washing up method is related to the water consumption. water method can be named as the predominant method for washing Because the analysed variables violate parametric assumptions, up. Forty-five percent of all the trialists who stated that they the Spearman’s correlation coefficient rS was calculated. A bivari- wash the dishes manually (n = 284) do the dishes this way. Similar ate correlation analysis was done using the statistical programme percentages in the groups of dishwasher owners and non-owners PASW Statistics 18 (IBM Corporation, Armonk, NY, USA) for were evaluated to wash up under running tap water (dishwasher the variables ‘total water consumption’ and the ‘frequency of owners = 43%, dishwasher non-owners = 46%). This way of dishwashing steps done under running tap water’. There is a sig- washing up remains also as the main dishwashing method in almost nificant positive relationship between both variables [rS = 0.71, P all investigated countries. Exceptions are consumers from (one-tailed) < 0.01]. An increase of the number of dishwashing Australia/New Zealand (AU/NZ) and Southern Africa (ZA) where steps performed under running tap water relates to an increase in the majority of people replied to do the dishes in a sink filled with the total water consumption. A significant correlation between water. the variables ‘total water consumption’ and the ‘frequency of The video analysis shows that over 50% of the consumers in dishwashing steps done in a filled sink’ cannot be confirmed, five of the test countries (RU, LATAM, KR, JP, ME) do more than which means an increasing number of steps done in a filled sink 70% of all dishwashing steps under running tap water (Fig. 7). does not result in higher water consumption. This is due to the Countries like Hungary (HU), China (CN) and the United States fact that several dishwashing steps can be done with just one (US) tend to combine both methods. The majority of people from sink filling without any water changes in between.

Figure 5 What is your preferred way of doing the dishes by hand?

Finally, a statistical analysis was done to clarify if there is a In compliance with previous research findings (Stamminger significant difference in the water consumption of consumers who et al., 2007; Berkholz et al., 2010), this consumer study provides washed up predominantly under running tap water compared with also a wide range of measured water and energy consumption data those who mainly washed up in a water-filled sink. That means as well as cleaning results, which demonstrated that dishwashing people who washed up more than 70% of all dishwashing steps habits vary dramatically between countries and regions. In addi- under running tap water in the test were compared with consumers tion, the study points out that under the tested conditions, almost who washed up less than 30% of all dishwashing steps under all dishwasher models achieve a better cleaning result and use less running tap water. Because all variables violate again parametric water and energy compared with the consumer tests. This is espe- assumptions, the Mann–Whitney U-test was used. The total water cially valid for the dishwasher results measured in the normal consumption of consumers who washed up more than 70% of all programme. washing up steps under running tap water (median = 148.19 l) Nevertheless, it should be pointed out that the presented differed significantly from consumers who washed up less than findings are based on specific test conditions. The approach of 30% of all washing up steps under running tap water but instead this research is limited because of its simulated test setup. Real- more than 70% of all steps in a filled sink [median = 75.57 l, life conditions in the respective countries may differ from the U = 2374.50, z =-5.36, P (two-tailed) < 0.001, r =-0.39]. results summarized in this study. This is due to the fact that factors like cultural differences in cooking practices, household Conclusion and outlook sizes and living conditions, for example, in urban or rural areas could not be taken into account but may have a deep impact on Compared with existing investigations, the presented study pro- household practices. Therefore, future investigations need to be vides a deeper insight into worldwide washing up habits by includ- conducted which need to include social and psychological ing both European and non-European countries into the focus of factors too. In addition, more detailed analysis needs to be done research. New insights are found about country-related washing with a representative consumer sample for each of the investi- up practices that show a connection between the water use for gated countries in order to verify statistically the presented manual dishwashing and the impact on water consumption. Par- results. ticipants from all continents took part. In addition, automatic dish- The video analysis clearly shows that consumers apply different washer tests were included to compare the resource consumption water usage methods for manual dishwashing. In the correlation and cleaning performance of both manual and automatic dish- analysis between the water consumption measures and the used washing within a laboratory test. manual dishwashing method, the findings indicate that washing up

Figure 6 What is your preferred way of doing the dishes by hand? (AU/NZ: Australia/New Zealand, manual dishwashing; JP: Japan, manual dishwashing; KR: Korea, manual dishwashing; CN: China, manual dishwashing; ME: Middle East, manual dishwashing; ZA: Southern Africa, manual dishwashing; DE: Germany, manual dishwashing; HU: Hungary, manual dishwashing; RU: Russia, manual dishwashing; LATAM: Latin America, manual dishwashing; US: United States, manual dishwashing). under running tap water especially has a high impact on the water For people to be more aware about the importance of a sustain- consumption compared with washing up in a filled sink. able usage of resources, deeper discussions and communication Comparisons between results of both the questionnaire and the are needed about both the consequences of a non-reflected water videos demonstrate that the majority of the consumers are aware and energy use. But also the potential savings consumers can of their dishwashing method but not about the consequences of achieve when using a dishwasher instead of washing up by hand their behaviour on the resource consumption. The survey showed needs to be more highlighted. The first step has already been done that a high percentage of consumers are still of the opinion that by the appliances industry and related businesses by developing manual dishwashing uses less resources than automatic dishwash- both more efficient machines and campaigns that promote the ing. Furthermore, the majority of people believe that a dishwasher ecological benefits of automatic dishwashing. Nevertheless, strong achieves poorer cleaning results than manual dishwashing. promotions do not seem to be enough to overcome the barrier of Reasons for these findings can be found in the fact that a high consumer behaviour. Consumer communication needs to be both percentage of participants (67%) did not have a dishwasher at more focused on the target audience and more culturally sensitive. home and therefore could not estimate the benefits that automatic More realistic approaches are needed. Slogans and metaphors do dishwashers have against manual dishwashing. not seem to effect big changes in peoples’ mindsets. But showing Washing up dishes is not a common topic in consumers’ minds. simple and more engaging solutions that are easy to understand It is a mundane and frequent household routine that is not and realize into daily life habits and routines might achieve a reflected. Its aim is to achieve clean dishes in the first place. The higher impact. Therefore, future investigations should lay their environmental impact that manual dishwashing has compared focus on developing country-specific communication and educa- with automatic dishwashing is less important to people proven by tion tools. For this purpose, the findings of this research provide this survey. the basis of a better understanding about consumer behaviour.

Figure 7 Percentages of consumers per country according to the percentages of dishwashing steps done under running tap water (AU/NZ: Australia/New Zealand, manual dishwashing; JP: Japan, manual dishwashing; KR: Korea, manual dishwashing; CN: China, manual dishwashing; ME: Middle East, manual dishwashing; ZA: Southern Africa, manual dishwashing; DE: Germany, manual dishwashing; HU: Hungary, manual dishwashing; RU: Russia, manual dishwashing; LATAM: Latin America, manual dishwashing; US: United States, manual dishwashing).

Nevertheless, there are still countries with a low market satura- References tion of automatic dishwashers due to a low income, cultural boundaries and harsh living conditions, especially in rural areas Association of Home Appliance Manufacturers (2005) Household elec- with insufficient infrastructure. The usage of an electric appliance tric dishwashers, ANSI/AHAM DW 1-2005 (revision of ANSI/AHAM in these countries is not yet a realistic target. However, a contri- DW-1-1992 and AHAM DW-1-2004). Washington, DC. bution to a sustainable behaviour on dishwashing can be achieved. Ballantyne, R., Connell, S. & Fien, J. (1998) Students as catalysts of Consumers need to be better educated about best hand dishwash- environmental change: a framework for researching intergenerational influence through environmental education. Environmental Education ing practices, for example, by demonstrating the difference in Research, 3, 285–298. doi:10.1080/1350462980040304. water consumption when washing up under the running tap instead Berkholz, P., Stamminger, R., Wnuk, G., Owens, J. & Bernarde, S. of in a filled sink (Fuss et al., 2001). Influencing adults who are (2010) Manual dishwashing habits: an empirical analysis of UK con- already set in their behaviour can be realized more efficiently by sumers. International Journal of Consumer Studies, 34, 235–242. laying the focus on children’s education. Research findings dem- doi:10.1111/j.1470-6431.2009.00840.x. onstrated in several studies that children are more open to new Deutscher Verein des Gas- und Wasserfaches (2004) Arbeitsblatt W 551: insights and in experiencing new circumstances compared with Trinkwassererwärmungs- und Trinkwasserleitungsanlagen; Technische adults. Therefore, they can be seen as a ‘key audience for envi- Maßnahmen zur Verminderung des Legionellenwachstums; Planung, ronmental messages’ (Ballantyne et al., 1998, p. 285). Errichtung, Betrieb und Sanierung von Trinkwasser-Installationen. Bonn. Europäisches Komitee für Elektrotechnische Normung (2008) EN Acknowledgements 50242, 2008: Elektrische Geschirrspüler für den Hausgebrauch – Messverfahren für Gebrauchseigenschaften. Brussels. The authors would like to thank Reckitt Benckiser Ltd. and BSH European Commission (2008) European energy and transport, Home Appliances Ltd. for supporting this research. trends to 2030 – update 2007. Brussels. [WWW document].

URL http://www.energy.eu/publications/KOAC07001ENC_002.pdf dishwashers. Final Report, Draft Version Tasks 1-2. [WWW docu- (accessed on 17 January 2011). ment]. URL http://www.ecowet-domestic.org/index.php?option= European Environment Agency (2005) Household Consumption and the com_docman&task=doc_download&gid=86&Itemid=40 (accessed on Environment, EEA Report, No. 11, Copenhagen. [WWW document]. 10 April 2011). URL http://www.eea.europa.eu/publications/eea_report_2005_11/ Richter, C.P. (2010) In-house Consumer Study on Dishwashing Habits at_download/file (accessed on 17 January 2011). in Four European Countries: Saving Potentials in Households with Fuss, N., Bornkessel, S., Mattern, T & Stamminger, R. (2011) Are Dishwashing machine. Schriftenreihe der Haushaltstechnik Bonn, 2, resource savings in manual dishwashing possible? Consumers apply- Shaker Verlag, Aachen. ing Best Practice Tips. International Journal of Consuemr Studies, 35, Stamminger, R., Elschenbroich, A., Rummler, B. & Broil, G. (2007) 194–200. Washing-up behaviour and techniques in Europe. Hauswirtschaft und Grady, T. (2004) Dillingen: washing its way to success. Appliance Wissenschaft, 1, 31–40. Magazine.com, Issue April, Los Angeles, CA. [WWW document]. United Nations (1987) Report of the world commission on environment URL http://www.appliancemagazine.com/editorial.php?article= and development: our common future. New York. [WWW document]. 487&zone=1&first=1 (accessed on 17 January 2011). URL http://www.un-documents.net/wced-ocf.htm (accessed on 2 International Electrotechnical Commission (2009) IEC October 2011). 60436:2004+A1:2009(E): electric dishwashers for household use – United Nations (2005) World population prospects, the 2004 revision, methods for measuring the performance. Geneva. highlights. New York. [WWW document]. URL http://www.un.org/ International Institute for Sustainable Development (2002) The Sustain- esa/population/publications/WPP2004/2004Highlights_finalrevised.pdf able Development Timeline, 3rd edn. IISD, Winnipeg, Manitoba. (accessed on 17 January 2011). [WWW document]. URL http://www.iisd.org/pdf/2002/ US Energy Information Administration (2001) Residential energy con- sd_timeline2002.pdf (accessed on 17 January 2011). sumption survey, 2001, Appliances in U.S. households, selected year, Japan Electrical Manufacturers’ Association (2008) JEMA-HD 084: 1980–2001. Washington, DC. [WWW document]. URL http://www. methods for measuring the performance of dishwashers. Tokyo. eia.doe.gov/emeu/reps/appli/us_table.html (accessed on 17 January Joint Standards Australia/Standards New Zealand Committee EL-015 2011). (2007) AS/NZS, 2007: Australian/New Zealand Standard TM, perfor- Vivian, S., Haslam, K., Soldner, M. & Sangster, M. (2011) Assessment mance of household electrical appliances-dishwashers. Part 1: of European energy and carbon profiles of manual and automatic methods for measuring performance, energy and water consumption. dishwashing. International Journal of Consumer Studies, 35, 187– Sydney. 193. doi:10.1111/j.1470-6431.2010.00986.x. Ministry of Knowledge Economy Korea Energy Management Corpora- Zentralverband Elektrotechnik- und Elektronikindustrie e.V. (2011) tion (2008) MKE’s notification 2008-99: regulation on energy effi- Zahlenspiegel des deutschen Elektro-Hausgerätemarktes 2011. ciency labeling and standards. Gwacheon-si, Gyeonggi-do. Frankfurt am Main. [WWW document]. URL http://www.zvei. Presutto, M., Stamminger, R., Scialdoni, R., Mebane, W. & Esposito, R. org/de/publikationen_veranstaltungen/publikationen_clownloads/ (2007) Preparatory studies for eco-design. Requirements of EuPs publikationen_der_fachverbaende/?no_cache=1&tx_ZVEI (Tender TREN/D1/40-2005) Lot 14: domestic washing machines and pubFachverbaende_pi1[realId]=608 (accessed on 2 October 2011).