8kW Solar System: Savings, Cost, and Other Financial Aspects

Feature image for the 8kW Solar System article. The image shows a solar installing on a ladder, climbing to a roof with solar panels.

An 8kW solar system has the potential to generate 12,168 kW of solar energy per year. The initial investment is likely around ~$9,100 and will take about 2-3 years to fully pay off; however, it’ll save you ~$3,800 per year on electricity bills. You see the logic? This is why people are going solar.

Neat, no? So let’s get into the details. Here’s everything you need to know about installing an 8 kW solar system.

How much does an 8kW solar system cost in Australia?

All brands are different, but the average cost of a solar system in Australia is about $1,146 per kW. It’s different for each state, of course. It’s better to get quotes from CEC-certified installers for accuracy, but here’s a list you can refer to:

CityCost per kW ($)Total Cost for 8kW ($)

Oh, by the way. The 8kW solar system prices above aren’t set in stone. Ask your installer for the final cost since it’ll all depend on so many factors.

How much power does an 8kW solar system produce?

Once again, the answer to this question depends on so many factors. We’ve got a separate write-up if you’re down for a deep dive, but let me speak about it a little here. The factors that affect solar production are:

  1. panel’s angle and tilt
  2. power ratings
  3. install location
  4. daily weather patterns

However, just to give you an answer, 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)

Get 3 Solar Quotes From Quality Local Installers.

How many panels are in an 8kW solar system?

Few things we need to calculate this.

  1. Your solar panel’s power rating
  2. Your system size (8 kW or 8000 watts)

Let me illustrate. Say you choose to install Canadian Solar’s BiHiKu Bifacial Mono Perc. Yes, that is a hell of a name. Nonetheless, these panels have a rated capacity of 420 watts (W).

  • number of solar panels = system size ÷ solar panel rated capacity
    • 8000 W ÷ 420 W/panel = 19.05 (then round up)
    • 20 solar panels

Let’s talk about a different option. For example, say you’re installing panels with rated capacities of 320 watts only.

  • number of solar panels = 8000 W ÷ 320 W/panel
    • 25 solar panels

For further reading:

How much roof space would you need for a 8kW solar system?

You may be sensing a pattern here because, again, this depends on a few factors.

  1. dimensions of your solar panels (every brand has different measurements, but the average is 1.7m x 1m)
  2. # of panels you need to install (for this example, it was 20 panels)

So, just to reiterate, the higher the wattage rating of your solar panels, the fewer panels you’d need to install. Meaning, the less roof space you’d need installed. Once again, let’s illustrate!

You’re installing 20 pieces of 420W panels at average dimensions (1.7m x 1m). This means you need 34 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 20
      • 34 m2

The financial implications of an 8kW solar system

Let’s talk about how your monthly savings look, your ROI, and your payback period. We have other articles about these, but let’s discuss them here a little.

How much money can you save with an 8kW solar power system?

And the pattern lives on; this also depends on a few variables. How much money you save depends on:

  • location
  • initial investment
  • monthly energy consumption
  • the electricity cost of your area

We also have a more in-depth dialog around this in another one of our articles. If you’re in a rush, you can find below wide estimates of the monthly and yearly savings you may get with each capital city.

CityMonthly Savings ($)Annual Savings ($)

Get 3 Solar Quotes From Quality Local Installers.

What about ROI and payback periods?

It may come as a surprise to some, but the payback period might not be as far into the future as it may seem. Let’s look at your payback period calculations and your ROI. Spoiler alert: it’s astounding!

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.

CityROI (%)Payback Period (Years)

So now, ROI is actually over 1000%. Wow! And your payback period is just about two and a half years. Of course, these are averages and oversimplified calculations. We simply cannot account for every possible thing that can happen. It’s even likely that payback comes around the 6th to maybe 10th year, depending.

Still, though, that gives you about twenty years of free solar energy. That’s still a huge win, and that’s why people are going solar.

Conclusion: Would your household benefit from an 8kW solar system?

Absolutely! Solar systems are the future. Not only does it help you, but installing solar panels and using clean energy to reduce the power bill for many households helps the planet on a larger scale as well.

Also, an 8kW solar system is getting into robust territory. Which means that you are likely to produce excess solar power, which you can send back to the grid. Meaning, if FiTs or feed-in tariffs are in play, you may increase your earning potential by just using your system.

Still need help? This may have all been a rough guide, but we have so much more reading material to assist you with anything and everything. Alternatively, you can always ask a professional. In that case, we have a network of pre-vetted solar installers that can give you 3 FREE quotes right away.