Lowering water temperatures in the cleaning step of a dishwashing program to 30°C leads to reduced energy consumption and decreased cleaning performances on persistently soiled dish- and cookware and of fatty soilings on hydrophobic surfaces. This study focusses on the question if the observed decline of the cleaning performance can be compensated for by aligning the formulation of the dishwashing detergent. A Design of experiments-method is used to quantify the effects of detergent components on the cleaning performance in mathematical models. The calculated models are used to adjust the amount of those components in a detergent formulation that increases the cleaning performance in low temperature electric household dishwashing. The modeled formulation has been verified in practical experiments.

Decreasing resource consumption concerning electricity, water and detergents in the framework of automatic dishwashing is not only determined by technical improvements. First and foremost, the use phase, in other words, the consumers and their choices, for example, the type of dishwasher, the kind of dishwashing programmes selected and the method of pretreating dishes, play an important role in terms of saving energy. To investigate the current dishwashing habits in Germany, 4 000 private households were asked about the usage of automatic dishwashers and the general dish treatment in everyday life. The results of the survey have shown a broad range of consumer behavior due to individual dishwashing habits. It also became obvious that consumers who more frequently use the energy saving “eco programme” tend to pretreat some dishes, such as pots and pans, with additional resources more often than the households who use other programmes. Therefore, the study reveals that a holistic view due to all resources consuming dishwashing steps is necessary to deduce adequate consumer recommendations for saving energy, water and detergents.

To further reduce energy consumption of dishwashing programmes and still obtain satisfying cleaning results, water temperatures in the programme steps are decreased and running times are prolonged. To which extent the cleaning factor duration is able to compensate for temperature has been insufficiently researched until now. This study quantifies the effects of a pre-rinse step, of the duration and water temperatures in different dishwashing programme steps on the cleaning performance and energy consumption in mathematical models. Using those models it is shown that even a (cold) pre-rinse step increases the cleaning performance and that energy consumption is reduced by 25–28% and the cleaning performance decreases, especially on heavily soiled load items and of fatty soilings on plastic surfaces, if the water temperature in the cleaning step is lowered to 30°C.