I just saw an advert for a Bosch dishwasher, which reminds me there’s a common misconception about how much water dishwashers use compared to washing by hand, and confusion over which is the most economical. The ad claims a Bosch dishwasher uses as little as 9 litres of water – “a lot less water than washing up by hand – saving as much as 50 litres for a similar load”. The ad also describes how much more hygienic dishwashers are too because they can wash in higher temperatures.
It’s a good advert for dishwashers in general as it points out that used properly, they can be more economical than washing by hand – especially if the hand washer has the tap running to rinse dishes. Of course it’s only part of the story though, and if we looked at the total environmental impact of building and transporting dishwashers and the impact of their factories and eventual disposal then washing by hand would score a lot more points.
Another article quotes a manager at Hotpoint/Indesit saying that using an efficient dishwasher can save up to 75% of water, 65 % of energy and 80% of time when compared with washing the pots by hand. Of course the time factor claim is derived from comparing the time spent loading and unloading the dishwasher with physically washing them, and not comparing the time a dishwasher takes, which is clearly much longer than washing by hand. The time saving only comes from the fact that although the machine takes longer to wash, you are free to use your time elsewhere, and that’s why they claim it’s quicker than washing by hand.
The dishwasher manufacturers are keen to get us to believe that it’s better to use a dishwasher and they are probably close, but as ever with adverts they often tend to give a two dimensional view which favours themselves. The Advertising Standards Authority has just upheld a complaint about this Bosch dishwasher advert saying that, “The commercial did not make clear that in some cases washing up by hand could be more water-efficient than using a dishwasher”.
I think it’s at least safe to say there’s maybe not as much in it as many people might assume these days but it’s not clear cut just yet. I wonder if you are as surprised as I was to learn that 70% of British households still do not have a dishwasher?