How efficient is my dishwasher?

In today's environment-conscious times it may be surprising to some that the dishwasher has become one of the most obligatory of 21st Century white goods - alongside washing machines and the humble refrigerator. Yet, when the worth of dishwashers is discussed, it seems that there is a definite divide between those who consider them efficient and green, and those who believe otherwise.

Of course, the old dishwasher versus the sink argument is a futile one. The reason simply being that those who invest in a new energy efficient dishwasher, do not rinse the plates before the go in and only use it when it is full are far more likely to be saving energy and water than those who use a full sink to wash two dinner plates.

A study by researchers at the University of Bonn in Germany found that modern dishwashers in fact use half the energy (due, in part, to heating up the water themselves), just one sixth of the water and less soap than hand washing. Dishes were also recorded as being cleaner after machine washing.

Although I don't doubt the truth in the Bonn report, water consumption is an intriguing matter. A quick browse on any kitchen/electronics site online will find a range of dishwashers that will vary quite considerably in size. While it was typical for older machines to use up to as much as 68 litres of water per wash, many of today's small models boast as little as 13 litres per cycle, while the average full size machine will use around 15 - around the same volume as one full washing up bowl.

When discussing the efficiency of dishwashers in comparison to the kitchen, it is also important to consider energy labels. In the UK (a similar ‘Energy Star' scheme is in operation in the US) the Department for Environment, Food and Rural Affairs (DEFRA) introduced energy labels for white goods in order to make the consumer aware of the efficiency of the product they are choosing. The labels, which must be used by law, run from A to G with the former being most efficient and the latter being less efficient. After having been in place since 2004, it is safe to say that most today are rated on the top end of the scale.