Estimating Energy Usage Guide

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How is Solar Energy used?: At any given time, solar energy is either consumed by your home or exported back out to the grid, only if you have generated more than your houses use which could earn you back money, eventually paying off your investment in a solar power system. Check your solar meter, it tells you how much energy you import and export, you can take advantage of a feed-in tariff, adding credit to your power bill. Your solar power system is always operating, when your off at work or if it’s a really sunny day out, your meter can be configured to export energy or you could alternatively store excess energy with a battery system.

Solar Feed-in Tariffs

Solar Feed-in Tariffs in South Australia are known as Voluntary Retailer Contributions, most SA electricity retailers offer a buyback program for electricity you export to the grid.

As of January 2020, rates on offer from electricity retailers include:

  • AGL: 14.2c per kilowatt-hour
  • Energy Australia : 11.5c per kilowatt-hour
  • Origin: standard – 10c , Solar Boost – 18c per kilowatt-hour
  • Diamond: currently 12c per kilowatt-hour


How big of a system should I get?

Going Solar, it would be best to use the minimal amount of energy as possible, to optimise your energy savings and save more. The number of solar panels you should use, would depend on your current energy usage and energy goals. There are two keys aspects to consider when thinking of what size of system is suitable for your home:

Energy Usage

Your electricity usage varies depends on your habits and how many people are in your household. These numbers are only estimates, it largely depends on how many appliances you use and how often; not the size of your house. Best to look at your power bills to know your average energy use in kilowatt-hours (kWh), and it changes over the months and seasons.


  • A regional home with two adults and two kids, might use between 30 to 50 kWh a day depending on how many appliances you use.
  • An adult couple with no kids might use between 15 kWh to 30 kWh a day.
  • A single adult in an apartment might use a minimum of 10kWh a day.

Calculating Payback Period

Solar energy is an investment, crucial information on making your decision on a solar system. Calculating your payback period can be complicated and depends upon your consumption patterns, location, energy tariffs and solar feed-in tariffs, and the cost and quality of your system. You can increase savings and lower the payback time on your solar system by increasing the amount of solar you use and avoid electricity from the grid. A larger system may have a higher upfront cost but may potentially payoff more than your initial investment.

For example:

If you had a 4.3 kw system which may cost 3000$, producing an average of 13 kw a day, the payback period would be 3 years compared to a 1.5kw system costing 2000$ that would produce 5kw a day, the payback period would be 5 years. The shorter the payback period, in the case of inverter failure where warranty is 5 years, the savings within the 3 years may be enough to afford another system.

 Future circumstances

If you’ve looked at installing a new pool, starting to work from home, or welcoming a new member of the family. Also consider how long you intend to stay at your current home, it is not ideal if your payback period is longer than your planned stay. You should choose the size of your solar system with your future circumstances in mind. It’s much easier and more cost effective to install a larger size solar system, then it is to expand in the long run.

What’s Next?

Choosing sizing of your solar power system, reduce the amount of energy from the grid and save money. These are some factors to consider when determining the size of your system.

1.Review your electricity bills: when are you most using energy, and how much energy are you using?

Send your electric bills over to our team and we can help you review them.

2.Understand where best to place your solar panels.

As the sun faces different directions depending on time of day, our team can take a look at your roof for potential panel placement.

3.You may be eligible for incentives

Your electricity provider may provide a feed-in tariff when applied for. A feed-in tariff pays you for excess energy generated by your solar system, that goes back into the grid. You may also be eligible for financing options from your energy provider.

4.Calculating payback period

This being the length of time it takes for your solar system to pay back your initial investment and enjoy saving money and free electricity!

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