12kW Solar System Cost

Updated: May 4, 2022

12kW solar systems are increasingly becoming popular for large households, thanks to the low cost of solar panels and generous government incentives.

The average cost of a 12kW solar system is $11,550. Depending on the quality of system, you can pay as low as $9,500 and as much as $13,200.

The thing with solar panels is that you always get what you pay for. You can get a cheaper system, but you may have to compromise on quality and reliability.

Low end $9,500
High end $13,200

What Is the Rebate Amount on a 12kW Solar System?

Solar power in Australia is now a cheaper alternative to electricity because of the rebates offered by the government. The rebate amount varies depending on the state you live in.

For a 12kW solar system in VIC and TAS, you will receive a rebate amount of approximately $5,240, while for NSW, QLD, SA, and WA, the rebate is around $5,544.

However, this price may fluctuate depending on the current STC value on the market.

How Much Power Does a 12kW Solar System Produce?

A 12kW solar system produces around 45kWh per day on average. However, factors such as location, climate, shading problems, solar panel tilt/orientation and quality may affect the system’s output.

The solar industry uses Peak Sun Hours (PSH) to calculate the output of solar panels. One peak sun hour is assumed to be equal to one hour because different regions receive different strength of sun rays during a particular time of the day.

How To Calculate Solar System Output

An efficient 12kW solar system generates about 45 units per day. But how do we reach this figure?

The output of a particular solar system is calculated using the following formula.

Solar system watts (12kW) x Peak Sun Hours (PSH) x75% = daily watts hours.

Since no solar panel can be perfectly efficient, the actual output is derated to 75% because of the panel’s variables.

Below is a practical example for a 12kW solar system.

12kW x 5.0PSH x 75% = 45kWh

12kW Solar System Output in Australia’s Capital Cities

City Approximate average daily energy yieldApproximate average annual energy yield
Adelaide43kWh - 49kWh18,396kWhs
Brisbane47kWh - 49kWh18,396kWhs
Canberra43kWh - 49kWh18,834kWhs
Hobart35kWh - 40kWh15,330kWhs
Melbourne37kWh - 43kWh15,768kWhs
Sydney41kWh - 46kWh17,082kWhs
Perth48kWh - 53kWh19,272kWhs
Darwin 50kWh - 55kWh19,272kWhs

How Much Can I Save With a 12kW Solar Power System?

A 12kW solar system can save you between $900 and $1,200 every quarterly bill or around $4,500 a year.

However, the actual money you can save from your system depends on the following two factors:

  • The solar feed-in tariff you get for the power you export to the grid
  • How much electricity you consume at the time of generation

Solar Feed-In Tariffs

Electricity costs around 18 to 30cents/kWh on average, while the current Feed-in-Tariff rate in the market ranges between 9cents/kWh and 13cents/kWh.

However, solar Feed-in-Tariffs are no longer the main incentive mechanism, and the rates have been significantly reduced. So, to get the most out of your solar system, you should consume most of the power it produces.


Every unit of solar power you use is a unit of electricity you do not need to buy from the grid. Therefore, you can save about 20 to 30 cents/kWh depending on the cost of your electricity.

How Can You Use As Much of the Solar Energy Produced As Possible?

  • Make sure you buy the right solar system size for your needs
  • Understand how you use electricity in your home and try to optimise your usage

Below are three examples to help you understand how important self-consumption is.

Example 1 – Suppose you use 100% of the solar energy your system produces. In this case, you will not export any power to the grid. If the cost of electricity increases by 5% every year, you will be able to save approximately $4,500 within your first year. By the time the panel’s performance warranty expires, you will have saved about $150,000.Example 1

Example 2 – If you use 50% of the power generated by your solar system and send 50% to the power grid, you will save about $2,700 within the first year.

Example 3 – If you use 0% power and send 100% of the energy your solar system produces, you will save around $1,000 within the first year.

Note: Self-consumption is the best way to get maximum savings from your system.

What Is the Average Payback Period?

The payback period for a 12kW solar system is around 3 to 6 years. Based on the annual 5% increase in the cost of electricity, you can expect to pay back your solar system within 6 years if you use 100% of the power produced by your system.

You will still need to pay for the maintenance of your system and replace your solar inverter after 15 to 20 years. But this is nothing to worry about if you will enjoy free electricity for more than two decades until your system becomes inefficient.

Finance Repayments on a 12kW Solar Power System

To fully pay for your 12kW solar system, you will need to make monthly repayments of between $400 to $650 every month.

Note: This figure varies drastically depending on the finance rates for residential solar power in your state.

What Kind of Household Does a 12kW Solar PV System Suit Best?

This solar system size is classified as commercial, so it is suitable for small businesses with low power needs.

The 12kW system is also ideal for larger households that use around 45kWh per day or within 24hrs with battery storage.

What Kind of Household Does a 12kW Solar PV System Suit Best

How Many Solar Panels for a 12kW Solar System?

A 12kW solar power system can consist of around 36 to 50 solar panels depending on their size. Check out the common panel sizes that can make up a 12kW system.

  • 50 x 240W solar panels to make 12kW
  • 48 x 250W solar panels to make 12kW
  • 46 x 260W solar panels to make 12kW
  • 40 x 300W solar panels to make 12kW
  • 37 x 330W solar panels to make 12kW
  • 36 x 335W solar panels to make 12kW

The panel size you choose will depend on the size of your roof.

How Much Roof Space Does a 12kW Solar Energy System Need?

Your roof space will determine the size of solar panels to choose. Panels with higher wattage tend to be more efficient, so you only need a few on your roof.

If you use 250W panels (each measuring approximately 1.7 m x 1m), you will need about 20.4 square metres of roof space.

What Can I Run With a 12kW Solar System?

A 12kW solar system can run several household appliances, including washing machines, lights, air conditioners, water pumps, etc.

If you decide to go entirely off-grid, below is a home system load reference to help you understand how you can use your 12kW system.

Load NameQTYLoad Rated PowerTotal Rated Power
Fax machine1150W150W
Washing machine1300W300W
Electric stove11000W1000W
Electric cooker1300W300W
Air conditioner(2HP)41500W6000W
Satellite TV receiver/VCD250W100W
Colour TV(32 inch)2150W300W
Water Pump1200W200W

Note: This is just for reference as different households have different needs and preferences.

Also, keep in mind that water pumps, air conditioners and refrigerators are inductive loads, so their starting power is three to six times more than normal power. To use this equipment, ensure you turn on the inductive load first.

12kW Solar System Key Numbers

DescriptionKey numbers
Number of panelsFrom 36 x 335W panels to 50 x 240W panels
Power output45kWh per day
Potential savings Between $900 and $1,200 every quarterly bill depending on the cost of electricity
Average payback period 3 to 6 years
Cost $13,000 to $18,000
Suited toLarge homes with more than average power needs

Is 12kW the Right Solar System Size for You?

The average electricity consumption for most Australian households is 20kWh, which makes 5kW solar systems the most convenient and cost-effective choice. However, 10 to 15kW solar systems are becoming popular for larger families with a high daytime power consumption.

If you use between 35kWh and 45kWh of electricity during daytime hours or within 25hours with battery storage, then the 12kW solar system is the right size for you. Also, if your business uses between 45kWh to 75kWh in a day, a 12kW system can help reduce your electricity bills.

Tip: If you use less than 30% of the self-generated power from your 12kW solar system, investing in such a large system won’t be cost-effective.

12kW Solar Energy System With Battery Storage

A 12kW solar system generates an average of 45kWh per day. So, a battery with a capacity of 33.6kWh would be enough for your system.

A battery calculator will help you know the exact number of batteries needed for your solar system.

Battery storage allows you to be more independent from the grid. However, battery backup options are quite expensive and may increase your payback period. Therefore, you should seek professional advice before installing battery storage for your solar system.


Yes, a 12kW solar system is an excellent investment for large households with high power needs. They can also help reduce electricity bills for small businesses.

The industry standard lifespan for solar panels is about 25 to 30 years when their efficiency drops below 80%. This is also the time when the panels’ performance warranty expires. You can still use the panels for several more years if their efficiency is not too low.

Yes, solar panels need maintenance to keep them in good shape. It is recommended to clean your solar panels every 6 months to one year to maintain their productivity, effectiveness and efficiency.

However, you may need to clean more frequently depending on the area you live in and how fast the panels accumulate dirt.

The national average solar panel maintenance cost is around $400, with an average range of between $300 to $700. On the low end, you can pay about $150, while the high-end cost can go up to $1,000.

This cost depends on where you live, your solar system size, roof orientation and the amount of dirt on the panels.

Yes, solar panels can potentially increase the value of a home because they help reduce monthly electricity bills. Most buyers are likely to buy homes with a solar system because of the potential savings from electricity bills.

Solar batteries have a lifespan of 5 to 15 years, depending on their type and quality. If you install a solar battery, you will need to replace them to match your solar panels’ 25-30-year lifespan.

There are several top-notch solar panel brands that provide high efficiency, performance and reliability.

The table below shows the best solar panels efficiency and material warranty.

Manufacturer Panel efficiency Material warranty
Sunpower 22.8%25 years
LG22.1%25 years
REC12.9%25 years
Panasonic 21.7%25 years
Q CELLS21.4%25 years