Fig. 1 shows a washing machine. Evaluate the environmental impact of this product across its life cycle and explain where a designer should concentrate effo...

A life-cycle evaluation considers impacts from material extraction through to disposal, then identifies the stage where design changes will make the largest overall difference.

• Materials: a washing machine contains a large mass of steel, polymers and a concrete counterweight. Extraction and processing of these materials give them significant embodied energy [3].
• Manufacture: forming, assembly and testing require energy, although this is less significant than the energy embodied in the materials [2].
• Distribution: the machine is heavy and bulky, so transporting each unit has a significant impact [1].
• Use: over a ten-year lifetime, energy and water used to heat water and pump it through cycles exceed the impacts of making the machine. Therefore use is the dominant life-cycle stage [3].
• End of life: the machine is heavy but largely recyclable if collected. However, mixed materials and bonded assemblies make separation costly [2].

Evaluation and conclusion: the designer should concentrate primarily on reducing impact during use: improve heater and motor efficiency and reduce water used per cycle. Durability and repairability are also crucial, because the machine must last long enough for its manufacturing impact to be spread over many years of efficient use [2]. A sustained whole-life evaluation that justifies this priority reaches 10–12 marks [12].