Electricity bill very high due to hot water system - What to do?

Hey guys,
I've recently changed homes. The first bill came in and the electricity read is 516.23 kWh(A) for the month for just myself.
Apparently this is more than a 5 person household uses.
I'm not doing anything crazy with the electricity, I have an energy efficient fridge, an old washing machine and dryer, and use an aircon unit.
I notice from looking at Energy Australia where it shows every half hour of usage there's a big spike when I shower, as well as a smaller spike at mid day and about 2am when I am not using any water, and some peaks when I must be washing the dishes.
It must be the hot water unit.

What can I do about this, if anything?
Obviously using the hot water is a part of life so I'm not going to sacrifice that, but is there any suggestions?
The bill is $140 and I haven't even been home during the day.



    Get an off peak rate to account for cheaper power to heat your hot water.
    Use less hot water when you shower / take shorter showers.

    • Switch from Energy Australia to a cheaper provider ASAP (they have some of the most expensive rates around)
    • If you own you home, consider replacing your HWS with a heat pump system and program it to run when your electricity rates are cheaper
    • Old washing machines and dryers also use a lot of electricity.
  • +3 votes

    Do you have gas?, Instantaneous gas water heater systems are good too.

  • +3 votes

    Turn down the temp of your hot water system and replace it if you can afford to do so.


      Unfort with newer installs you are forced to keep the tank temp high to stop bacteria. Then cool it with a tempering valve.

      I used to do the same and lower the tank temp but a kitchen reno meant a tempering valve had to go in. And electricity consumption increased a lot. Shifted to gas instant.


    516kw is 17kw a day. That's a little high, but it's no 5 bedroom house. My girlfriend and I average about 25-30kw a day, so similar.


      My girlfriend and I average about 25-30kw a day, so similar.

      A day is only 24 hours, your house is on average consuming 1,042 - 1,250 Watt of power, which is actually quite a lot. Perhaps you also have something that is nearing the end of useful life?

      Or maybe you have a big swimming pool……….


        No, all appliances are new, all bulbs are Hue LEDs, but we have a lot of electronics running all the time. We also have heating or cooling on (ducted reverse cycle), probably 250-300 days a year. I live in a 100+ year old house, and some parts just can't be insulated (like stained glass windows). I have servers/switch running, home assistant, security cameras etc, 24/7. I could bring power use down, but I don't really feel the need.


          We also have heating or cooling on (ducted reverse cycle), probably 250-300 days a year.

          Yeah that's why. By far the biggest energy consumption right there.


          I don't really feel the need.

          So not bothered by global warming, are you?


    The bill is $140

    $47 a month is nothing.

  • +2 votes

    Halo375 is right on the money. Turn the temp on your hot water service down. It's bizarre how many peeps pay to maintain a huge vessel of water at a very hot temperature, only to reduce that water to a much cooler temperature every time they use it, by mixing it with cold water!

    The next question is, 'do you own the joint'? If so, the most obvious answer is to get solar panels on your roof. To be honest though, something seems off/fishy here. Are you perhaps part of a 'body corporate' of some sort? It sounds to me like you are being way over-charged, given your meager usage…


    Take cold showers.


    Find the manual where possible, read what it says about adjusting the thermostat. If it has a user adjustable one, Set to recommended setting, anything higher is a waste.. To cool and bacteria etc will grow..
    From memory the tank should be a minimumim of 60°c to kill of bacteria, eg: legionella..

    If your system has one, the Tempering valve will regulate the temp to a maximum of 50°c into the property, you can adjust it to less, but shouldn't, as hot water for dishes etc could become an issue


    switch the hot water system to controlled load?


    I notice from looking at Energy Australia where it shows every half hour of usage there's a big spike when I shower

    Just curious to where you can see this level of detail with Energy Australia? My profile only shows what we use per quarter.


    What sort of hot water service is it? Lots of advice above regarding a hot water service that no one knows what it is.

  • -1 vote

    Copy and Paste my Comment from another forum

    I was renovating my whole house, and had no gas in my area.
    So I was force to used Electric Hot Water Tank
    So this is what I did

    Electric Hot Water tank + Solar Panels +[Paladin Solar Power Diverter]! = Decrease Utility Bill

    What you need is the missing link - Paladin Solar Controller

    • Excess Solar Energy is diverted to the Hot Water tank
    • Hot water tank act as a Battery, storing excess energy in the form of heat
    • Large Hot water tank last the night, for variety purpose Eg shower, kitchen tap, washing machine etc
    • By morning the Hot water tank get heated up again with Excess Solar Energy up to 70c
    • Instead of selling the KWH excess energy to the grid at 17cent/kwh, try to use as much which cost 30cent/kwh
    • On Days with bad sun exposure, the Paladin keep the Hot Water tank at minimum 40c
    • Check it out: http://www.paladinsolarcontroller.com.au/
    • Youtube: https://www.youtube.com/watch?v=wnuNXKzdxXI

    • Speak to Mark from Paladin, i deal with him when he came to my house

    • He does an initial consultation, to check whether the hot water tank and solar panel up for it
    • Very Friendly, easy to talk too
    • He is base in Brisbane too
    • Save loads on the Utility Bill

    (mod: removed referral solicitation)


      Honestly, I think thats just overkill and quite possibly poor ROI.

      Not gonna claim that I have the golden equation but I think its much more viable and simple:

      Heat Pump HWS + Solar Panels = Vastly Decreased bill (or in credit in my case)

      The heat pump HWS (which came at a low cost with the STCs) is set to heat water for about 2 hours when my solar panels are generating electricity at its peak, the tank retains the heat all the way till the next day when its heated up again. Have never run out of hot water in my household of three. I get paid for my excess solar power fed into the grid. Never had to paid an electricity bill ever since I got the solar panels; even though I have a no-gas, only electric household.

      • +1 vote

        Honestly, I think thats just overkill and quite possibly poor ROI.

        Was for me. Off peak hot water rates were low, like $30 per quarter. The unit was going to cost around $700 if I recall correctly. Would also be of limited benefit because we use most hot water in the evenings after the sun is gone.


          Yes, I thought so too. The whole setup just looked wrong to me for the following reasons:

          1. Keeping an electric tank - One of the most inefficient HWS options
          2. Diverter - Adding another component into the equation. Personally, I dont like having two things doing the same thing when I can just stick with one. Plus, its an added purchase expense (and maintenance?)
          3. Solar Panel output - Getting feed-in tariffs for solar exports is a great plus of owning as PV system as it speeds up ROI which can eventually start making you a profit even. Wasting that simply to heat water which may or may not be used in its entirety, to "decrease" bills which could have been eliminated completely; just looks wrong. Simply calling the hot water tank a battery does not make it so.

    I installed a timer for hot water system so it only turns on during off peak hours.

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