This study presents an overview of the washing up behaviour of consumers in the UK. Peoples' individual attitudes were observed as were the amount of water and energy used, the time taken and the cleaning performance. Additionally, manual dishwashing was compared with the use of automatic dishwashers. Participants were recruited to represent all geographic regions of the UK as well as forming a representative cross-section of the population. Each of the 150 participants washed a full load of soiled tableware based on the standard EN 50242 'Electric Dishwashers for Household Use -Methods for Measuring the Performance'. For comparison, the best selling dishwasher in the UK in 2007 was tested under the same conditions as those in the consumer trial. Additionally, consumers who owned a full-size dishwasher were asked to load it to the point when they decided that the dishwasher was full.The study shows that these consumers, on average, used 49 l of water and 1.7 kWh of energy, whereas the dishwasher used 13 l of water and 1.3 kWh of energy on average for the same amount of dishes under the conditions tested. Statistical analysis showed that these differences are significant. The dishes washed by hand were found to be slightly less clean than dishes washed in a dishwasher. For washing a full dishwasher load by hand, the participants needed, on average, 60 min, while they only took 9 min on average to load and unload the same amount of dishes in a dishwasher. The average participants were able to fill almost the full load into the dishwasher (96% of the items as used in a test following EN 50242).

This laboratory study presents an overview of the global manual dishwashing behaviour. 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 performance achieved. Additionally, manual dishwashing was compared with automatic dishwashers. Two hundred eighty-nine participants from 29 countries took part in this investigation. Each consumer had to wash up a complete soiled dishwasher load consisting of 12 place settings based on both international and local performance test standards for automatic dishwashers. Country-specific aspects such as tableware, food residues or 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 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. tions of the present without compromising the ability to meet those of the future' (United Nations, 1987, p. 51). 2 'In essence, sustainable development is a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development, and institutional bs_bs_banner

Global studies have observed many techniques of manual dishwashing causing different levels of performance and using quite different amounts of water, energy, time and detergent. It is not known, however, if these techniques are pre‐assigned to a person and persist when dishes are washed under different conditions, or are adapted to the specific type of dish‐cleaning process. Here we explored this question in a study with 40 test subjects selected equally from Germany and East European countries by asking them to wash two place settings of dishes with different amounts of soil three times. The results showed that the test subjects did not adapt their washing‐up behaviour to the amount of soil. In general, no significant differences were found in the water, energy and detergent consumption for all test subjects. Only the time used by the German test subjects to wash the fully soiled dishes was significantly longer compared with the dishes with only a quarter the quantity of soil, and no significant difference was observed for all other parts. The only significant difference found between the level of soiling of the dishes was the cleaning result achieved: The less soiled the dishes were, the better the final cleaning result was, and this related to all test subjects. This lends support to the proposition that the consumers did not adapt their washing‐up behaviour to the specific circumstances of the dishwashing job to be done but retained some pre‐assigned behaviour.