Solar Update: I paid just $1 per day to run a 4bdr home for 3 months

    Today we received our first power bill since having solar installed on our home and the savings are massive.

    The bill period runs for 91 days, from March 5th to June 3rd, 2020 and totals a massive $96.53. That translates to just A$1.06 per day.

    Our house is a 4 bedroom home with currently 2 adults, and our 2 year old daughter. We have lots of technology on in the house everyday with a couple of TV, phones, laptops all charging, a home office with computer monitor, lights, heating (gas), cooling (electric), cooking (combination) for just $1 per day is kind of incredible.

    Given seasonality of energy usage, comparing to the last bill (summer) isn’t really fair, so looking back to the same billing period 1 year ago, the savings are even more impressive.

    Billing periodkWh usedAvg cost per dayTotal Amount
    05 Mar 20 – 03 Jun 20648.840$1.06$96.53
    04 Mar 19 – 02 Jun 191,125.390$4.26$388.09

    This represents a year-on-year saving of $291.56 for just this quarter alone. You’ll notice the energy consumed and average cost per day dropped considerably, which is a result of our consumption drawing from the solar first, before the grid.

    Below is the detail of our energy usage cost, plus supply charge, minus our credit for feeding power back into the grid from solar generation. We made A$176.29 which almost entirely covered our usage cost.

    What is seriously impressive about that, is that we’ve barely made any lifestyle changes. At most, we’ve delayed the start of our dishwasher or washing machine by an hour or two, but this has only been done a few times, typically we just use power how we want and this bill proves that’s a very viable model for us going forward.

    On February 7th of this year, we had 6.5kW of solar panels installed, with a 5kW inverter and that’s proving to be one of the best financial decisions we’ve made.

    The full system details are:

    • 20 x SunPower 325W P-series All Black Mono Crystalline modules (SPR-P19-325) with 25 year product warranty and 25 year lineal performance guarantee
    • 1 x SolarEdge HD Wave 5kW solar inverter (SE5000H)
    • 20 x SolarEdge P370 DC Optimisers with: 12 year product warranty on inverter + 25 year product warranty on DC optimisers
    • Optional “Black Pack” – All associated mounting hardware and isolator shrouds to be supplied in a black finish for added aesthetic appeal.

    Our system cost $12,212.00, but thanks to the Solar Homes program in Victoria, we were out of pocket just $5,006.00 upfront, and have 4 years to pay back an interest-free loan to the Vic Government for A$1,888.00 (around $10 per week).

    Looking forward, I expect the energy savings to be a little less during the Winter quarter, but much more in summer. While projecting this quarter’s savings for an entire year won’t be accurate, its the best data I have available right now.

    With a quarterly saving of $291.56 (or $3.20 per day), that means we’re likely to be at least $1,169.44 better off per year. With the system costing us $6,888.00 that gives us a projected ROI after 5.8 years. I suspect the summer months will bring this forward be a year or even 2.

    With the panels featuring a 25 year warranty and performance guarantee over their life, the decision to add solar to our home looks to be a great investment. It’s not hard to see why more than 2.2 million homes and businesses made the same decision.

    Jason Cartwright
    Jason Cartwright
    Creator of techAU, Jason has spent the dozen+ years covering technology in Australia and around the world. Bringing a background in multimedia and passion for technology to the job, Cartwright delivers detailed product reviews, event coverage and industry news on a daily basis. Disclaimer: Tesla Shareholder from 20/01/2021


    1. That’s not an investment, it’s a handout. Also a handout with our children having to pay back the money. Someone has to pay for this, and since you are well able to afford it yourself, it is immoral to hand this off on someone else. Your return on investment calculation is wrong also. It neglects opportunity cost as well as depreciation. Which if you factor that in put the cost as barely worth doing sans handout.

      • Thanks Elvis, could disagree with you more.

        The scheme offers an incentive so more people can get solar, which decreases their expenses, leaving them with more disposable income for purchasing goods, all of which also create income from GST.

        Don’t forget GST from the panels is also returned to the Government, as well as additional income tax generated by solar businesses employing more people to manufacture, deliver and install solar.

        I’m confident the Government have done the maths that these returns outweigh the money spent on incentives.

        Regarding ROI, a calculation of money spent, by the time taken to return is a typical formula. In regards to opportunity cost, that’s difficult to calculate given the number of possible investment options. If I had taken the $5k outlay and left it to offset the mortgage, versus taken the money and put it into shares, or gone to the casino. That ends up being speculation, so I stuck with what is a calculable and common ROI.

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