Solar panels on rooftops

3kW Solar Systems: Price, Size and Power Output

The Australian solar market is booming as more people turn to clean and cost-effective energy solutions. Skyrocketing electricity prices have made solar an even more attractive option for Aussies who want to make their lives a little easier by offsetting a portion (or all) of their energy bills. And who can blame them? 

Now you may reside in a small household wondering what size solar system is right for you. Your system’s size is determined by its power output, which is measured in kW: if you’re wondering what kW stands for, check out our explanation of kilowatts and kilowatt hours.

For many smaller homes, a 3kW solar system is worth exploring. It may not be as popular as the bigger rooftop rigs being installed these days, but it still packs plenty of punch, especially if your home doesn’t guzzle that much power. 

In this guide, we’ll answer everything you need to know about 3kW solar systems in Australia so that you can make an informed decision about whether or not this is a suitable option for you.

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How many panels in a 3kW solar system?

A typical 3kW solar system will have between nine and 12 panels, yet the exact number will depend on the wattage of each panel as well as the amount of sunlight your home receives. Most 3kW solar systems will consist of panels that have a wattage (W) of 370 each, meaning a system of this size would likely only require nine panels. 

For a solar system of this size, your roof will need to have about 18 to 20 square metres of free space, given that most panels today measure 170cm by 100cm. You’ll generally notice that most properties with a 3kW solar system have the panels on one section of the roof, usually in the direction of where the best sunlight is. There may be other circumstances where a 3kW solar system may need more than the average number of panels, but this should be pointed out by your >installer.

How much kWh does a 3kW solar system produce?

A 3kW solar system will produce between 10 and 12 kilowatt hours (kWh) of electricity per day on average. This means that over the course of a year, you can expect your system to offset between 3,650 and 4,380kWh of electricity from the grid, or roughly two-thirds of what the average Australian residential property uses.

How much electricity a system of this size will generate depends on several key factors, including: 

  • Location: Including local weather and how much sunlight your panels will be exposed to 
  • Panel efficiency: The age and type of solar panels – monocrystalline, polycrystalline or thin film 
  • Roof positioning: The direction and positioning of the panels on your roof
  • Obstructions: Much like the positioning, any trees or branches that obstruct direct sunlight

How much does a 3kW solar system cost?

Solar panels on roof with city skylineThe price of a 3kW solar system will generally set you back between $3,000 and $5,000, depending on where you live and any rebates that are available. Although installation costs vary, there are small-scale technology certificates (STCs) nationwide, in which this scheme applies rebates to rooftop solar systems under 100kW.

Other price considerations include what your chosen solar installer is charging in your location, the brand of panels and inverter, and whether or not you’re looking to install a solar battery as well. The final cost you’ll pay for a 3kW solar system can usually be provided by your installer for free, and given it’s not a cheap endeavour, it’s worth arranging a few quotes to compare prices.

How much will a 3kW solar system save me?

To work out how much a 3kW solar system will save you, we first need to calculate a few key components while taking some assumptions on board. This is because every household is different from the next, so no two solar systems of the same size will yield the same savings over a quarterly billing cycle or year.

However, let’s look at the amount of yearly savings you can expect with a 3kW solar system if you’re purely using it to offset grid electricity being imported to your home. Please treat the figures below as a general guide only. 

Say you live in Sydney, and you pay 28 cents per kWh (c/kWh) for your electricity usage. Then we assume you use 16kWh of energy each day. Assuming your 3kW solar system covers 12kWh of your daily energy usage, you’re left with using 4kWh of electricity drawn from the grid. Of the $4.48 you’d be charged for daily power use without solar from the grid, you’d only pay $1.12 for electricity each day. This means that the remaining $3.36 would be offset by your solar panels, which over the course of a year amounts to more than $1,200. Cha-ching!

Keep in mind the above scenario only factors in usage charges, not electricity supply charges or other fees on your electricity bill. 

Compare solar plans & prices

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Ausgrid network in Sydney but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 3911kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Citipower network in Melbourne but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Energex network in Brisbane but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4613kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on SA Power network in Adelaide but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4011kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

How long before a 3kW solar system pays for itself?

It’ll usually take between three and five years for a 3kW solar system to pay itself back. Of course, there are numerous factors that will contribute to the payback period of solar panels. This includes whether you’re using the bulk of your power during the day and if you’re exporting any electricity back to the grid in exchange for a rebate, otherwise known as a solar feed-in tariff.

Again, there are other factors that will determine the buyback period, such as the initial installation cost (minus any rebates), the weather in your area, as well as how old and efficient your system is. Taking all these considerations into account, a 3kW solar system has the potential to save you a lot of money on your energy bills over an extended period of time.

Should you get a 3kW solar system?

Like all big investments, buying a 3kW solar system will ultimately come down to your personal situation. The good news is that the upfront cost of solar is on a downward spiral so splashing out now may pay off in the long run. While 3kW solar systems are not the biggest option on the market, they do pack a punch, especially if you live in a small household that is energy conscious. 

And don’t forget about the good you’ll be doing for the environment too, as you become less reliant on grid electricity. Saving money is great and all, but so too is generating your own renewable energy. In addition to the ongoing financial and environmental benefits, you’ll also likely be adding value to your home. And who wouldn’t want that?

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Jared Mullane
Energy Contributor
Jared Mullane was a content producer and editor at Canstar Blue for three years until 2022, most recently as Energy Editor. He holds a Bachelor of Journalism from Griffith University.

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