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10kW Solar System: Financial Aspects, Power Output, and More

Feature image for the 10kW solar system article. Image shows a large contemporary style house with rooftop solar panels on top of a hill on sunset.

A 10 kW solar system will cost roughly $10,000. Costly, yes, but it also saves you about $4700 per month. But given how modern systems last at least 25 years and might only take less than 3 years to pay off, this needs more than just a strong consideration.

That being said, I’m covering everything you need to know about residential installations of this size system. Below is a list of topics you’ll find here. Feel free to tap on any of the bullets if you want to skip sections.

What is the installation cost of a 10kW solar system?

In Australia, the average cost of a solar system is $1000 per kW. Of course, however, every state has its own average. For better accuracy, it’s best to get quotes from CEC-certified installers, but for your reference, here is a list of averages per capital city:

CityCost per kW (AUD)Total Cost for 10kW System (AUD)
Brisbane$950$9,500
Melbourne$1070$10,700
Sydney$980$9,800
Perth$1000$10,000
Adelaide$850$8,500
Canberra$1400$14,000
Average$1042$10,416.67

Bear in mind that the cost of the 10kW solar system mentioned above is subject to change. The components you pick, the installation’s complexity, and the installer’s quote are just a few of the variables that will affect the final installation cost.

How much electricity can a 10kW solar system generate?

The amount of solar power your system can generate depends on a number of factors, so there’s no definitive answer to this question either. We have another piece for that if you want to read more about it, though.

But, to put it briefly, these factors include your solar arrays’ orientation (angle and tilt), power ratings, installation location, and daily weather.

In any case, below are the projected daily, monthly, and annual power outputs for each capital city in Australia. Note that we used the PV Watts calculator for this, and we used the following parameters:

  • Roof pitch: 22.5%
  • Inverter efficiency: 96%
  • Quality and type of solar panels: Standard
  • Installation type: fixed, roof-mounted
CityDaily Output (kWh)Monthly Output (kWh)Annual Output (kWh)
Brisbane43.611,326.515,918
Melbourne37.061,127.4213,529
Sydney41.11,249.514,994
Perth46.141,403.3316,840
Adelaide411,25315,040
Canberra41.11,249.514,994
Average41.671,268.2115,552.5

How many solar panels do I need for a 10kW solar system?

You will need the power ratings of the solar panels you intend to install in order to compute this correctly. The system size (10 kW or 10,000 watts) is then divided by the power ratings.

For example, let’s say you have your eyes on the REC TwinPeak 5 with a power rating of 410W.

  • number of solar panels = system size ÷ solar panel rated capacity
    • 10,000W ÷ 410W
    • 24.39

Since you can’t really get 24.39 modules, you’d realistically need 25 modules of the REC TwinPeak 5 to get a 10kW solar system.

Now, let’s say you want to go the more affordable route and install solar modules with lower power ratings. In this next, example, let’s use 330 kW instead.

  • number of solar panels = 10,000W ÷ 330W
    • 30.30

Again, because you can’t install fractions of modules, you’d need about 31 of them.

Related: How many solar panels does your home need?

How much roof space would a 10kW solar system need?

Residential solar panels typically measure 1.65 meters in height and 1 meter in width. Every brand and model, though, will have a unique set of measurements.

Furthermore, the total number of panels needed to complete a 10kW solar system will determine how much roof space you need. So, if you also use solar modules with higher-rated capacities, you’ll require fewer solar modules. 

Let’s imagine for the purposes of this discussion that you selected modules with a rating of 410W and average size. In order to reach 10kW, you must therefore install 25 of those panels. This implies that 14.85 square meters of space will also be required. This is the breakdown of that calculation:

  • Step 1: Calculate the area of one solar panel
    • Area = height x width
      • 1.65m×1m
      • 1.65 m2
  • Step 2: Multiply the area of the solar panels by how many of them you need
    • Required roof space = solar panel area x number of panels
      • 1.65 m2 x 25
      • 41.25 m2

The monetary aspects of a 10kW solar system: savings, ROI, payback period

There are 3 main financial implications to investing in 10kW solar systems:

  • how much money you save,
  • how long it takes until they pay for themselves, and
  • Your return on investment

Let me briefly explain them to you.

How much money can a 10kW solar system save?

The table below shows how much you can potentially save on electricity bills per month and per year, depending on which part of Australia you live in.

Do note, however, that how much money you save still depends on other things, such as your electricity usage, the cost of power, and how much you paid to get your system installed.

CityMonthly Savings (AUD)Annual Savings (AUD)
Brisbane$358.21$4,298.4
Melbourne$366.90$4,402.8
Sydney$424.69$5,100.0
Perth$397.55$4,770.77
Adelaide$489$5,866
Canberra$332.01$3,984.13
Average$394.73$4,737.35

How long until the solar system pays for itself? What about ROI?

How long until your system pays for itself (payback period) is more than likely sooner than you’d think. Subsequently, your ROI (return on investment) will likely also be much, much higher than the cost to get it installed.

But, like pretty much everything else about 10kW solar systems, there are other factors that affect both. Nevertheless, you can use the equations below to calculate your own ROI and payback period predictions.

  • ROI = (total savings ÷ total cost) x 100
  • Payback period = total cost ÷ annual savings

If you’re like me and you hate math, you can always refer to estimates that our team calculated.

CityTotal Cost (AUD)Annual Savings (AUD)ROI (%)Payback Period (Years)
Brisbane$9,500$4,298.41132.21%2.21
Melbourne$10,700$4,402.81028.79%2.43
Sydney$9,800$5,1001305.10%1.92
Perth$10,000$4,770.771176.15%2.09
Adelaide$8,500$5,8661721.41%1.45
Canberra$14,000$3,984.13612.25%3.52
Average$10,416.67$4,737.351129.32%2.27

That’s an average ROI of over 1100%! Not to mention, the payback period of just a little over 2 years. Granted, both of those averages are based on the best conditions.

In the real world, you’re never going to have the most ideal conditions every day. Still, though, this is super impressive. Even if it takes you 6–10 years to pay your system off, you’ll still have free energy for 2 decades. Maybe even more.

Conclusion: is a 10kW solar system right for your home?

Well, how large is your family? The energy production of a 10kW solar system is perfect for the electricity usage of larger households (5 or more people). If you need more, you can always opt for larger systems or, better yet, invest in battery storage.

A battery allows you to store your energy for use after daylight hours. This, in turn, maximizes self-consumption and further cuts your electricity bill.

If you’re still unsure, you can always ask professionals. And, in that case, we have a network of pre-vetted solar installers that you can count on. Let us know and we’ll happily give you 3 FREE quotes from them.