Home Forums General Discussion Energy Star Ratings of Washing Machines

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    Renee Rushton

    Hi all,

    I’ve recently had a query regarding front loading washing machines and energy efficiency. The client was interested in the difference in efficiency of machines that have an internal heating element and just the single cold water input versus the dual input models which would use the house’s existing hot water heating system.

    I can’t find any information on the energy star rating info pages regarding what the assumptions are in terms of home hot water heating systems – would it just be a standard electric hot water cylinder? In which case the efficiency would be more or less the same for an internal heating element and a hot water cylinder – unless your hot water cylinder is really far away from your washing machine and heat is lost along the way.

    Anyway the person was planning on using a wetback and eventually a solar hot water heater to heat the water and was after a dual hot and cold water input as this seemed like the more efficient option. But the majority of the front loaders have a single cold water input – and some of them have excellent energy star ratings. What makes these machines so efficient?

    Also, has anyone come across a machine for under $1000 with a dual input? They all seem really expensive.


    I guess if people are relying on a standard electric HWC, then it’s almost always going to be at least marginally more energy efficient to heat the water in the washing machine, rather than heating it in the cylinder and moving it through pipes to the machine. So in this case a single input machine is fine.

    It may be cheaper to source the hot water from the cylinder if the cylinder is on a different meter than the washiing machine, eg. night rate or some other controlled rate on a separate meter.

    If their hot water cylinder uses a heat pump, solar or wetback then potentially they can make savings if they have a hot water input.

    Of course if they normally do cold washes, then none of this maters. If you’re comparing washing machine star ratings, then check the assumptions about whether the rating applies to hot, warm or cold washes, and ask the person whether they expect to do many warm or hot washes. Also check the machine default settings, many will do a warm wash if the temperature is not set manually each wash, so if the user expects to do mainly cold washes it may be worthwhile to find a machine that defaults to cold.

    And finally, consider a front-loader. If they are going to be using a lot of hot washes, one way to save is just to use less heated water per wash. If you know how many litres of hot water is used/heated between different models, it will give you a better basis to choose between models and how much effort to put into getting a separate hot water feed.


    Norman Smith

    For a report on washing machines aearch the Consumer website; it will then cost you around $15 to buy the specific report, unless they/you already subscribe.
    Cheers, Norman


    HI Renee!

    It could be worth speaking to Christian at EECA if he doesn’t reply here.


    Renee Rushton

    Thanks Alex – yep we were already onto the front loading machines as the most efficient. They will be using a wetback and then solar to heat their water so I think it will be advantageous to use a dual input machine.

    Already onto the consumer reports too thanks Norman.

    The client bought a dual input LG in the end.

    Thanks so much for all your help!!


    Paul Hansen

    Front loader, cold wash, hang the washing in the UV solar energy system to kill the bugs. Hot water washing is over rated. A big plus of front loaders is approx 1/2 the water consumption. So 75L for a full wash as opposed to 150L. That’s a lot of water to use once and send back down the plug. We are on tank water so this is a strong point to consider for the summer time. My machine then pumps into a grey water holding tank that I can use to water the garden.

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