Is a Dishwasher really better for water and energy efficiency?

When it comes to washing up, is machine or man power best?


| Out with the old |

As with advancements in other white goods, better design and new technologies have brought substantial improvements in efficiency – so much so that replacing an old dishwasher can more than pay for itself because of reduced energy and water usage. An Australian report for the federal government committee on Equipment Energy Efficiency (E3), found that from 1993 to 2005, water usage in the newer dishwashers was slashed by 39 per cent and energy usage was reduced by 36 per cent. Newer models are now even designed so you don’t need to rinse your plates before you wash, saving on the pre-rinse water too! And all that mucky work.


 | Averaging it out | How do dishwashers stack up compared to washing by hand?

According to a study by the University of Bonn, the average amount of water a person uses to wash their own dishes by hand every day is 10.5 litres. It doesn’t seem like a lot when taking into account cooking of meals. However, the average household in Australia is between 2-3 people, meaning that it would be between 21-31.5 litres a day. Within the study, Europe’s best machines only used around 15 L and consumed between one kilowatt-hour (for a standard cycle) and two kilowatt-hours (intensive cycle) of energy to wash and dry the dishes. The hand-washers, meanwhile, averaged a whopping 103 L, with one enthusiastic scrubber using 447 L!

That still may not sound so terrible, but when compared to the average modern dishwasher on a full cycle, which consumes 15 litres, it’s not great. That’s stacked to capacity by your household, not just per meal. So if you’re like most households that only need to run their dishwasher once a day, you’ll want to drop your hand washing habits, stat.

| Labels are your friend |

It’s understandably tedious to hunt down all the details of your dishwasher and try to figure out the exact amount of water and energy it uses per load, but these labels do all the hard work for you.

First of all, there’s the Energy Rating Sticker that you’d be able to find on any dishwasher, or other appliance, available for purchase. This is a government run program which provides a star rating based on the amount of energy it uses in a year, so you’re able to compare it to other dishwashers of a similar capacity. This means you can figure out how your dishwasher compares to others on the market – the more stars, the better!

Much like the energy efficiency rating, the government also has the Water Efficiency Labelling Scheme (WELS). Similar to the labels for energy efficiency, it works on the same six star rating, and notes the average number of litres of water your dishwasher uses per minute. This is an easy way to gauge how much water you use every time you put on a load. The most efficient dishwashers under this scheme use half the amount of water as an average model on the market, saving you money and offering peace of mind.

| Brand benefits |

Considering a dishwasher is an investment, and the average Australian keeps their dishwasher for over seven years, it’s worth seeing whether big brands are willing to try to cut costs to both you and the environment. Proven effective, this could sway the mind of any hand washing devotee.

Taking into account the aforementioned statistic that the average hand washer uses 10.5 litres a day to wash up, will modern eco-friendly dishwashers be able to compete? Top-rated dishwasher brand Miele’s latest units can use as little water per cycle as 6.5 litres. This was part of the company’s plan to reduce the amount of water use by its dishwashers by 85% over the last 30 years. Meanwhile Bosch dishwashers use ActiveWater technology, promising to maximise efficiency of dish cleaning through uses of targeted water distribution, filters, faster heating and increased water circulation. What that amounts to is a similar performance of only 6.5 litres to wash the dish equivalent of 13 meals.

| Stars are significant |

Spending a bit more on a machine with more stars makes a big difference.The government’s energy rating checklist shows that each additional energy star equates to 30 per cent less energy consumption. As well, each extra water star means the machine will use 15 per cent less water.

Improved water efficiency also means less detergent can be used, which is better for our waterways. And if you choose a dishwasher detergent that contains no phosphates or which is certified by Good Environment Choice Australia, your ensuring our waterways aren’t impacted by your dishwashing choices either.

| Cycles & Options |

Some dishwashers have an eco-friendly or economy cycle for washing lightly soiled loads to save extra water and energy for lower bills. Some dishwashers have a Delayed Start option so you can set the cycle to start during off-peak power periods for utility bill savings.

| The verdict |

Provided you’re using it correctly, it’s much more water and cost efficient than washing by hand. Even though there will be some things that require a gentle wash in the sink, if it can go in the dishwasher, it should go in the dishwasher. Properly stacked dishwashers use less water and are usually better on the electrical energy front compared to hand-washing. Here are some general tips for reducing impact either way.

  • Always scrape your plates into the bin with a knife or fork, and avoid pre-rinsing under a running tap.
  • If washing by hand, use two sinks – one full of hot, sudsy water for washing, and one filled with cold water for rinsing. This will reduce excessive water used by running water to rinse.
  • For dishwashers, make sure the machine is always full before you press ‘go’.
  • OR choose a model with a good auto-sensing program or half-load option, so you can wash a smaller number of dishes more often and economically.
  • Clean the filter regularly for increased efficiency.
  • If you’re in the market for a new dishwasher, shop by the stars, choose a machine with a very high energy efficiency score and low water usage.
  •  Select a machine that has a fast/eco wash cycle, and wait until before you go to bed to run a cycle or choosing a delay start option so you use energy at cheaper rates.

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