13kW Solar System: Power Generation, Cost To Install, & More

Feature image for the 13kW Solar System article. Image shows a solar installer on the rooftop of a mansion at sunrise.

This is a large solar system and is for people with high energy usage. A 13kW solar system can generate about 20,364 kW of solar power per year on average and will cost you about ~$15k initially.

Not to worry, though, as the payoff can be as short as two and a half years. Plus, this investment will save you ~$6,100 per year on energy bills.

So, let’s get into it. Here’s everything you need to know about installing a 13 kW solar system.

How much does a 13kW solar system cost in Australia?

In Australia, expect to spend somewhere around $1,146 (per kW) on a solar system. That’s the average since it’s a different cost sheet for each state. You can check quotes from CEC-certified installers for more accurate data.

But here’s a list you can refer to:

CityCost per kW (AUD)Total Cost for 13 kW System (AUD)

The 13kW solar system prices above aren’t set int stone. Make sure to speak with your provider for the final costs since it’ll all depend on so many factors and you can opt to add battery systems or different types of inverters as well.

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How much power does a 13kW solar system produce?

There’s no one answer to this question, as it all depends on a few factors. Namely:

  1. panel’s angle and tilt
  2. where the panels are facing
  3. power ratings
  4. install location
  5. daily weather patterns and potential blockages

We’ve got dedicated articles on this topic as well.

However, let’s draw out an illustration for conversation’s sake. I listed the estimated daily, monthly, and yearly outputs for each Australian capital city below. This was computed using the PV Watts calculator under the following settings:

  • 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)

How many panels are in a 13kW solar system?

We’ll need the panel’s power rating and your system size (13 kW or 13,000 watts) to get the answer.

Let’s illustrate. Say you install Solarwatt’s Vision AM 4.0 (400 Wp). These panels have a rated capacity of 400 watts (W).

  • number of solar panels = system size ÷ solar panel rated capacity
    • 13,000 W ÷ 400 W/panel = 32.5 (then round up because you can’t have a fraction of a panel)
    • 33 solar panels

Let’s view a different option. For example, say you’re installing panels with rated capacities of 250 watts only.

  • number of solar panels = 13,000 W ÷ 250 W/panel
    • 52 solar panels

For further reading:

How much roof space would you need for a 13kW solar system?

Again, it’ll depend on a few factors.

  1. panel dimensions (average is 1.7m x 1m)
  2. number of panels needed (33)

So, as we’ve learned before, you can minimize the amount of roof space you need by availing of higher and higher-wattage solar panels. Once again, let’s illustrate!

In our example, you’re installing 33 pieces of 400W panels at average dimensions (1.7m x 1m). This means you need 52.8 square meters of roof space. Here is the calculation:

  • Step 1: Calculate the area of one solar panel.
    • Area = height x width
      • 1.7m×1m
      • 1.7 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
      • 1.7 m2 x 33
      • 52.8 m2

The financial implications of a 13kW solar system

Moving on, let’s see what your monthly savings, ROI, and payback period look like. Spoiler alert: It’s pretty good!

How much money can you save with a 13kW solar power system?

How much money you save depends on:

  1. your geographical location
  2. initial investment
  3. monthly energy consumption
  4. electricity cost.

Although we have articles dedicated to some of these subjects, I’ll briefly illustrate below some wide estimates of the monthly and yearly savings you may get with each capital city.

CityMonthly Savings ($)Annual Savings ($)

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What about ROI and payback periods?

Just as I’ve said before, the payback period isn’t as long as it seems. Let me illustrate your payback period calculations and your ROI.

To calculate this, we need numbers on installation costs and savings.

Here’s an easy equation you can use:

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

Feel free to use the numbers listed above if you want an estimate, or check the table below.

CityTotal Cost (AUD)Annual Savings (AUD)ROI (%)Payback Period (Years)

You can see that your ROI is greater than 1000%. Plus, your payback period is just two and a half years. Also, since these panels are warranted for 25 years, that gives you about 22 years of free solar energy. Although these may be averages and oversimplifications, that’s still a huge win!

Conclusion: Would your household benefit from a 13kW solar system?

As far as solar power systems go, this one is strong and robust. Yes, most definitely, your household would benefit from this system. In fact, with a large solar system like this, you’re bound for energy independence soon!

That said, some things to keep in mind are:

  • excess solar power and if tariffs are in play
  • battery costs (optional but recommended)
  • How much energy do you need per month?
  • inverter capacity (get only as many panels as this can support)

Also, please don’t forget how much space you need for this system. Make sure to measure your roof space and speak with your installer about it. They should be a ton of help. All these, and your system’s energy production capabilities will drastically reduce your electricity bills.

By the way, our network of pre-vetted solar installers can give you 3 FREE quotes right away, too. Make sure to get in touch!