Sunday, 19 May 2013

What’s greener – dishwashers or washing by hand?

Instinctively greens tend to believe that hand washing their dirty crocks must use less energy than a dishwasher. Think again. At least two scientific studies have found  that a dishwasher will use less water than washing by hand thus saving the energy of heating up so much water.

Greens tend to only replace white goods once they are broken – I know I do. Again, this is not necessarily the right thing to do. The Life Cycle Engineering and Management Research Group at the University of New South Wales says that buying a new dishwasher which uses less water and energy than an older versions can be better. The improvement in performance more than eliminates the embedded energy of the new machine.

So what we feel instinctively should be green isn’t always the greenest thing to do.


  1. Dishwasher is only more sustainable if:

    1. You never rinse your dirty dishes before putting them in the dishwasher;

    2. If you don't consider the cost in energy and materials for actually making the dishwasher (which most of the time will be shipped by boat from Asia).

    3. If, when hand washing, you do not plug the sink and let the water flow freely.

  2. The Life Cycle Engineering and Management Research Group of the University of New South Wales disagree with you on the embedded energy and materials. They concluded that the water and energy saving from having a newer more efficient dishwasher outweighs the energy/ material cost of the new dishwasher.

    Please do have a look at their research using the link posted above.

    Two separate studies, in Germany and in the UK concluded that dishwashers use less water than hand washing and therefore less energy.