3kw vs. 5kw - Which Solar System Size to Choose?

3kw vs. 5kw – Which Solar System Size to Choose? Find Out Here!!

Comparing the Popular Solar System Sizes – 3kw vs. 5kw

The very first step when choosing any solar PV system is to determine the size of the system you want and the capacity (in kilowatts, kW) of the system you need.

Generally, the residential solar market has sorted itself out into…..

5 typical solar system sizes. They are:

The above are based on the size rating of one of the two main parts of any solar system – the solar inverter.

Here it is important to mention that the power capacity of the solar panels tends to vary depending on which system brand you pick to go with.

Investing in a solar PV system’s a big decision.

So be confident when choosing the right one!

Among above 5 typical system sizes, 3kW and 5kW are two of the most popular residential solar PV system sizes in Australia.

And when it comes to picking out between a 3kW vs. 5kW solar system, there are advantages of both.

Let’s discuss some of them, so that you can make a more informed decision.

3kw vs. 5kw Solar System | Advantages

  • A 3kW system has 9 – 12 panels and generates around 5kW per day, whereas a 5kW system has 20 panels and generates around 20.8kW per day.
  • With the 3kW system, 80% of your power is consumed while 20% energy goes back to the grid. On the other hand, with the 5kW system, 70% energy is consumed within the household while 30% back to the grid.
  • To install a 3kW solar panel, you’ll generally need around 15m2 to 25m2 of roof space, depending on the wattage of the panels. Whereas for a 5kW system you’ll generally need around 20m2 to 40m2 of roof space.
  • The amount of energy a 3kW and a 5kW solar system produce depends on a number of factors – including how much shade they get throughout the day (even the time of year) and the tilting of the panels and where they are located.
  • The average costs of 3kW solar ranges from $3,490 to $5,600 and a 5kW solar cost range from $4,990 to $8,000.
  • For a 3kW solar, $200 per electricity bill cycle, the savings tend to average out at about $120 – $180 per billing cycle. On the other hand, $350 per electricity bill cycle for a 5kW solar, the savings are believed to be between $180 and $300 per cycle.
  • The solar rebate for a 3kW system is around $2,390 while the solar rebate for a 5kW system is around $3,990.

3kW vs. 5kW solar system

3kw vs. 5kw Solar System | Price tags or Better value – What will you go with?

Smaller the system, lower the price tags

One of the main reasons that a 3kW solar system is more attractive than a 5kW solar PV system is that the cost for the 3kW system is almost inevitably lower compared to a 5kW system.

The table below shows the average price differences between 3kW and 5kW solar systems in Australian capital cities.

On an average, the price of a 5kW system is about $2,000 which is without any doubt, more than a 3kW system.

Average 3kW Solar System Price

Average 5kW Solar System Price





















Larger Solar PV Systems Better the Value

Although a 5kW system is highly expensive, but they also produce more energy.

Often it is found that the increase in cost is disproportionately small if compared to the increase in energy production – in short, greater value for money.

3kW vs. 5kW solar system

According to the table below, on a dollars-per-watt basis, 5kW solar systems are inexpensive than 3kW systems by about 28c/W.

3kW Solar System Price ($/W)

5kW Solar System Price ($/W)






















3kw vs. 5kw Solar System | Payback


The Solar System ROI is almost similar for both the systems.

A good quality 3kW solar system will payback for itself in 3 years.

But because the solar offers an immediate return-on-investment through utility bills, you’ll be saving more from day one.

On the other hand, if we talk about 5kW solar payback, the system will pay for itself within 2.5 to 4 years.

It’s worth remembering that the less power you transfer to the grid, the less time it will take to pay off your system.


3kW vs. 5kW solar system

The Final Verdict

At this point we have established that both 3kW and 5kW solar systems are theoretically equal when it comes in terms of their investment-worthiness.

From the above analysis, we found that a 3kW systems are perfect for small working families with an electricity budget of $220 or more per cycle, where a 5kW system are perfect for medium to large households with an electricity budget of $350 or more per bill cycle.

But, if you want to know our opinion, then we would like to recommend you to choose a 5kW system as it has become one of the most popular in Australia in recent times.

Besides this, a 5kW system is ideal for larger households and you can easily get a payback within about 4 years.

Although it’s more expensive from the outset, but remember, with a 5kW system you are going to save more in the long run. You will have more energy during peak times and also the energy will be available for the battery storage so that you can go completely off the grid.

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