Assessment of European energy and carbon profiles of manual and automatic dishwashing

Domestic energy use generates a significant proportion of anthropogenic global carbon emissions. To date, many reduction programmes in the domestic sector have focused on increasing energy efficiency and reducing energy consumption in the home. Consumer goods manufacturers also have a role to play in raising consumer awareness and encouraging behavioural change. The first step in identifying opportunities for decreasing carbon emissions is to understand emission sources and quantify their relative importance. This study investigates energy and associated carbon dioxide equivalent (CO(2)e) emissions from dishwashing. Specifically, it assesses the relative CO(2)e profiles of washing dishes by hand (manual dishwashing) and using a machine (automatic dishwashing) and included consumer behaviours. This study also specifically considers the relative efficiencies of appliances used to heat water. The study followed recognized international protocols for life cycle assessment and carbon footprinting. On this basis, the same assessment boundary was applied to both processes. Output comparisons were based on: 1 the sources of energy uses (e. g. electricity, gas, etc.); 2 the associated CO2e emissions; and 3 the cost of energy used. Various data sources have been used and are referenced. Calculations of appliance energy use for manual dishwashing considered country-specific data for water heaters including fuel types and efficiencies. Automatic dishwashing appliance energy use was calculated from machine manufacturers' electricity use data. The conclusions show that, for each of the six European countries assessed and based on the study assumptions, the automatic dishwashing process uses less life cycle energy than manual dishwashing and consequently results in lower CO2e emissions. Differences in country-specific energy generation mixes, consumer behaviour and boiler efficiencies show variations in the outcomes; overall, however, there appears to be a clear benefit in switching from manual to automatic dishwashing both in terms of CO2e emissions and in terms of annualized costs.