Case study: Washing machines

Within the context of the EcoTopTen product initiative, it was examined for the case of the washing machine product group (Rüdenauer and Grießhammer 2004) what contribution further product innovations and, respectively, more efficient user behaviour on the part of consumers when washing (i.e. lower washing temperatures, optimized loading of the machine) can deliver.

The functional unit was defined as “washing the amount of laundry arising in one year in an average private household”. The costs were calculated for one private household: purchase costs of the washing machine attributable to one year of use; costs of water, electricity and detergent consumption; costs of wastewater disposal.

The following four alternatives were studied:

• Alternative A: Low-cost washing machine and average user behaviour

• Alternative B: More efficient washing machine (lower water and electricity consumption, automatic load detection) and average user behaviour
  
• Alternative C: Low-cost washing machine and optimized user behaviour (optimized loading and lower washing temperatures than the average)
  
• Alternative D: More efficient washing machine and optimized user behaviour

The table beside shows the findings. Aggregate environmental impact and global warming potential are roughly proportional, so that the GWP, a more readily understandable measure, was used for the further evaluation (e.g. in the figure beside).

In addition, in order to aid comparison, the findings were normalized – i.e. greenhouse gas emissions expressed as a proportion of the greenhouse gas emissions of an average household, and costs expressed as a proportion of the annual consumer spending of an average household. The scale in in the figure beside is set accordingly.

Conclusions for product development

The Eco-Efficiency Analysis reveals that the behavioural options are substantially more eco-efficient (this is due to the circumstance that it has become usual today to wash inefficiently, using excessive washing temperatures and loading the machine poorly).

It follows that further product development should concentrate on “intelligent” washing machines, which signal the weight of the laundry when loading the machine through a display and recommend a minimized temperature. The additional cost of this function, however, should not be high, as consumers could quite well select the appropriate load or low temperature without a display, with little extra effort and at no extra cost.

The reason for the great importance of appropriate washing behaviour is that little scope now remains to further reduce water and energy consumption through technological refinement of washing machines. It is in the field of detergents that further technical optimization is still possible, for instance by introducing special low-temperature detergents.