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5kW Solar Systems

Power generation of a 5kW solar system in Adelaide

To give you a better understanding of the power output of a 5kW system, let’s consider the theoretical possibilities.

In peak sunlight (more on peak sunlight below), 1kW of panels with a 1kW inverter would produce 1kWh of electricity per hour. By extension, 5kW of panels with a 5kW inverter would produce 5kWh of electricity per hour.

So how much will this actually generate on an average day in Adelaide? As we know, the sun isn’t a light globe you can just switch on and off, directly above your panels whenever you need power. Instead, it moves across the sky under varying cloud and atmospheric conditions.

Peak sun hours refer to the quantity of solar energy available in an area during a typical day.

With that in mind, how do we estimate power output? Enter, ‘peak’ sun hours. Peak sun hours are not just hours of daylight, but they refer to the quantity of solar energy available in an area during a typical day. A peak sun-hour, specifically, is an hour during which the intensity of sunlight is 1,000 watts per square meter.

In Adelaide, we receive an average of 5.6 peak hours of sunlight a day, over the period of a year. Based on that figure, we could deduce that a 5kW system will generate 28kWh per day.

But, wait! There are some variances that ultimately reduce this figure. For example, panel angle, direction and degradation, as well as efficiency losses due to energy transfer and heat (yes, solar panels are less efficient in higher temperatures). On average these losses can reduce a system’s performance by around 25%. All of a sudden our 28kWh becomes 21kWh! That’s a significant difference, and worth noting in your decision to purchase a system.

Suitable For

Moderate electricity users who are home some days, or low to moderate users who are looking to add a battery at some point.

Maximum Peak Sun Output

3.75kW (5kW, less 25% for efficiency losses)

Average Daily Power Generation


Real World Usage

(Simultaneous Usage During Peak Sun)

1x Small Fridge (200W)
1x Small wall split A/C at maximum power (3.5kW)


4x 55” QLED TV (200W ea)
1x Retina 5k 27-inch iMac (262W)
1x Sound Bar + Subwoofer (45W)
1x PS4 (140W)
2x Medium to Large Fridge (700W ea)
1x 1000W Microwave

5kW solar system prices

In South Australia, a decent 5kW solar system could cost anywhere from $4,250 - $11,000*

The pricing variation comes down to the quality and reputability of the inverter(s), the panels, and the installation. In some cases you might also have site-specific requirements, such as splitting your panel arrays across multiple roof faces.

Looking for an indication of pricing for your situation? Start by getting an instant solar quote.

Instant Solar Pricing

Savings and payback on 5kW solar systems

The payback period for 5kW systems varies according to your electricity usage, roof orientation and pitch, shade and other property specifics. In general, however, you could expect to recover the cost of the system within a 3-7 year period, in South Australia.

The figures below are a guide, and may not reflect your actual costs.

Possible Payback Scenario

  • System Price:
  • Annual Savings:
  • Payback Period:
  • $4,800
  • ~$1,600
  • 3 Years

Should I consider a larger system?

A 5kW system is a great middle of the range system and a popular choice amongst average Australian homes. However, if you’re looking to make a real dent in your electricity bill and have a bit more roof space, you could also look at moving up to a 6.6kW solar system.

Should I add batteries?

Before buying a battery for the 5kW system, you could also consider the 6.6kW system, which is only a few panels larger.

When considering a battery, it’s important to consider a few variables, such as your provider’s feed-in tariff, your household energy usage, and the amount of solar energy produced in winter months. That is, in winter, a smaller system may not even provide enough energy to charge your battery, especially if energy usage in the home is high.

Feel free to reach out to us to discuss your options and what might be best suited to you.

How many panels make up a 5kW system?

A 5kW solar system is typically made up of between 12 – 18 panels (20m2 – 30m2).

This number could change as panel technology improves over time.

If you’ve made it this far, well done!

We hope this has given you a good baseline to make your decision on solar. However, if you’re more lost than when you started, that’s ok, it’s complex stuff! We’d love to help - give us a call on (08) 8374 1491, or contact us here.

In the meantime, why not check out some other common system sizes.

3kW Systems6.6kW Systems10kW Systems

*This price accounts for the STC government rebate (accurate October 2020), which is scheduled to end in 2030. However, each year that you delay your installation, the rebate amount is reduced, and therefore the out of pocket expense on the purchase of a solar system increases.