6kW solar systems or now more commonly seen as 6.6kW solar systems are becoming increasingly popular amongst Australian homes thanks to a number of factors, including their affordability, ample size & ease of approval when it comes to connecting to the grid. This article provides an overview of (almost) everything you need to know if you’re considering a 6kW solar system for your household, including pricing, energy yields and their attractiveness as an investment.
How many panels are in a 6.6kW solar system? How much area required?
A modern-day 6.6kW solar system using 330-watt (W) to 400W modules will consist of about 17-20 solar panels. This number has reduced a lot over the last decade.
Each panel generally measures out to 1.7m2, so the roof area required for a 6.6kW system will be about 34-38m2 – or possibly more depending on how your roof is laid out and whether you require tilt frames (which need to be spaced out more than panels mounted flush on the roof).
An important note about inverters for 6kW and 6.6kW solar systems
Are 6.6kW systems the new 5kW system?
Although your system may have 6.6kW worth of solar panels, don’t be surprised if the proposed inverter for your system is only 5kW. On basically every electricity network in the country, 5kW inverters are pre-approved for grid connection which means that 5kW inverters are much more common to come across than 6kW ones. Many of the 6.6kW solar systems on the market are therefore ‘overclocked‘ systems with a 5kW inverter.
A 5kW inverter can be overclocked by a maximum of 33% under the Clean Energy Council‘s installer guidelines. This means a 5kW inverter can support up to 6.6kW of solar panels, but can’t quite get to 7kW. Overclocking your inverter offers benefits such as greater solar energy yields in the early morning and late afternoon – even if ‘peak’ production is clipped back to 5kW during the middle of the day.
How much does a 6.6kW solar system cost?
Solar Choice has been keeping track of residential solar system prices since August 2012 with our monthly Solar PV Price Index. Based on this data we can advise that the average 6.6kW solar system will cost around $0.89 per watt or $5,900 after the federal STC rebate has been deducted as of July 2024.
See the full breakdown by Australian city in our table below which we update each month:
6kW solar system costs by Australian state capital
6kW
Adelaide, SA
$5,030
Brisbane, QLD
$4,990
Canberra, ACT
$5,490
Darwin, NT
$9,320
Hobart, TAS
$6,390
Melbourne, VIC
$5,130
Sydney, NSW
$5,230
Perth, WA
$5,130
All
$5,840
The price of solar systems do, however, vary widely in the market. A more cost-competitive 6.6kW solar PV systems consisting of cheaper, low-end products will cost less, while premium offerings will generally be pricier.
History of 6kW solar system prices in Australia
The below graph shows the price history of the last couple of years. You can see the pricing has remained relatively flat however there are some differences depending on your location in Australia.
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How much energy will a 6.6kW solar system produce?
Depending on a number of factors, the actual power output of a 6kW solar power system will vary. These variables include:
Location and local climate
Orientation and tilt angle of the solar panel array
Whether there is any shade cast on the panels
The performance of the individual components (primarily the panels and inverter)
Location is one of the main determinants of solar system energy yields, as the amount of sunshine falling on a solar system’s solar panels directly affects the system’s output. The table below provides rough approximations for how much energy a 6kW solar system will produce, based on Bureau of Meteorology and PVWatts data.
Please note that these figures are indicative only and that we have endeavoured to be conservative in our estimates, using a system efficiency rate of 75%. Also, note that these figures are annual averages – in reality, energy yields will be higher in the summer and lower in the winter.
More and more households have battery storage in mind when they purchase a solar system. The smallest size we generally recommend you install if you’re considering batteries either now or in the future is 6.6kW. For low to medium energy users, a system of this size will generally provide plenty of surplus energy for storing in a battery.
How long is the payback period on a 6.6kW solar system?
The benchmark by which most solar shoppers measure their panel’s performance is the payback period – the number of years that the system will take to ‘pay for itself in energy bill savings & feed-in tariff credits.
The table below shows indicative payback periods, ‘internal rate of return’ (IRR) and annual savings in the first year for 6.6kW solar systems in a handful of Australian capital cities based on average prices as of July 2023. (Note that these are outputs from our Solar System Payback & ROI Estimator tool – which we encourage you to explore with your own numbers.)
Keep in mind that returns may be better for systems whose price points are lower, or if you achieve a higher level of solar self-consumption. But also be mindful that you’ll want to be selective about the products and companies that you consider – some deals are too good to be true.
Indicative payback periods for 6.6kW solar systems
6.6kW System Cost
Electricity Price
Feed in Rate
Self Consumption Rate
IRR
Annual Savings
Payback Period (Years)
Sydney
$5,140
30c
7c
30%
25%
$1,269
4.0
60%
40%
$1,982
2.6
Brisbane
$5,070
27c
5c
30%
22%
$1,128
4.4
60%
37%
$1,803
2.8
Melbourne
$5,260
25c
3c
30%
17%
$889
5.7
60%
31%
$1,557
3.3
Perth
$5,360
32c
5c
30%
25%
$1,293
4.1
60%
41%
$2,119
2.5
Adelaide
$5,460
36c
3c
30%
24%
$1,253
4.3
60%
43%
$2,251
2.4
Hobart
$6,250
30c
9c
30%
20%
$1,263
4.8
60%
32%
$1,922
3.2
Canberra
$5,510
28c
8c
30%
24%
$1,296
4.2
60%
36%
$1,922
2.8
Darwin
$9,320
27c
9c
30%
16%
$1,503
6.1
60%
23%
$2,073
4.4
Assumptions:
Average daily energy use = 25 kWh
6.6kW System cost is the average price from Solar Choice’s price index for a fully installed turnkey system
Excludes state-based solar grants/rebates (e.g. Solar Victoria rebate)
Pricing comes from Solar Choice’s Price Index for July 2024
How much power will a 6.6 kW solar system produce?
A 6.6 kW solar system typically produces between 19 to 30 kWh per day, depending on your location in Australia. For instance, in Melbourne, you can expect about 21-24 kWh per day, while in Darwin, the system could generate around 28-30 kWh per day. Factors such as the orientation and tilt of your panels, local climate, and shading can also influence the system’s output.
What size battery do I need for a 6.6 kW solar system in Australia?
The ideal battery size for a 6.6 kW solar system in Australia depends on your energy usage patterns. For low to medium energy users, a battery with a capacity of 10 to 13.5 kWh is usually sufficient to store the surplus energy generated by the solar system. This setup can help you maximize self-consumption and reduce reliance on the grid.
How much roof space is needed for a 6.6 kW solar system?
A 6.6 kW solar system requires approximately 34 to 38 square meters of roof space. This estimate is based on using modern 330W to 400W solar panels, which typically measure around 1.7 square meters each. The actual space needed may vary depending on your roof’s layout and whether you need tilt frames for optimal panel placement.
How much should a 6.6 kW solar system generate in winter?
In winter, a 6.6 kW solar system will generally produce less energy compared to summer due to shorter daylight hours and lower sun angles. For example, in Melbourne, you might expect the system to generate around 15-20 kWh per day in winter, compared to 21-24 kWh in summer. The exact output will depend on specific weather conditions and system setup.
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Jeff has consulted on over 20MW of commercial solar projects, ranging from SMEs to ASX top 100 companies. Jeff has also provided independent advice to 100s of residential solar, battery and EV charging customers across every state in Australia. He holds an MBA from the Australian Graduate School of Management and is an expert in business strategy and financial analysis.
Hi Solar Choice,
Looking at getting solar and the more I do the more confusing it seems to be, no two quotes alike.
One I am favouring are quoting a 6.8Kw Canadian 340w 144 cell x 22 panels with Fronius 6kw phase inverter and Fronius Smart metre for full monitoring purposes Solar PV for $8800.00
Everyone else has quoted using a 5 kw inverter and I am advised while a bit more expensive it will in the long run give me more of a return on a cheaper electricity bill.
My quarterly bills are currently averaging out at $670.00
If you are able to offer any advise I would indeed be grateful.
Thank you Simon
Hi Simon,
Solar panel arrays are allowed to be oversized relative to the inverter capacity – so a 5kW inverter with 6kW worth of panels is relatively common these days. When you take this approach, your solar system will produce a bit more energy in the mornings and afternoon, but will flatline in the middle of the day, when the sun is at its brightest. The overall effect is that you get more energy out of a 6kW solar panel / 5kW inverter system than you would out of a 5kW panel / 5kW inverter system – especially during the times that you’re likely to use it (morning & arvo).
This approach is particularly attractive for two reasons: 1) Some electricity networks only allow up to 5kW of inverter capacity to be connected without extra red tape, and 2) 5kW inverters are very common and therefore often less expensive than other ‘niche’ sizes because of the amount of competition in this size range. So you might find a a good deal in a system that oversizes the panel array.
It sounds like the 6.8kW Canadian / 6kW Fronius inverter setup that you’re currently leaning towards is a decent quality system – on the ‘premium’ end of things. According to our pricing figures, a ‘premium’ 7kW solar system retails for about $1.20 per watt – or about $8,400 on average nationally (we don’t have specific pricing for 6kW systems, so I encourage you to check out the table and look for your nearest capital city). I also note that this price doesn’t include extras like monitoring, so that could explain the higher price you’re looking at (and also: some places have higher overall prices – especially VIC and TAS).
I hope this helps!
What is the rebate rate of the solar power installed 2 years ago?
It was 68 cents but we got a letter from the service prowider ( AGL ) it is 60 cents now. We changed from Origine because it paid only 66 cents…
Is there a better deal with any of other company?
Do you have a list I can select from?
Thanks a lot
Attila
Hi Attila,
I think you’re referring to feed-in tariffs as opposed to a rebates. Regardless the options available to you will depend on what state you live in. Unfortunately, we don’t have a comprehensive list of what’s on offer from energy providers as we help people get the best solar PV installation deal for them. I’d recommend you have a look at a comparison site for energy company’s.
As a rough guide, the base level in NSW two years ago was 60¢ per KWh, although energy retailers did offer various options to encourage people (like yourself) to switch. There is currently no mandatory feed-in tariff in NSW so switching to another energy provider may result in you loosing the 60¢ rate, the best on offer in NSW is now 8¢ per KWh! If you speak to AGL they may be able to tell you why the rate was dropped and their competitors may by able to advise as to whether you will still be eligible for the earlier Premium tariff.
Sorry we can’t be of more help, good luck!
Thank you for your independent assistance as there is so much information that I obviously don’t understand.
As I have had “my fingers burnt” with Chinese manufactured goods (they seem to provide cheap & only lasting 1/4 or 1/3 of previous products & so I don’t buy to throw out as I don’t like our disposable age !! Graeme
Graeme,
Thanks for the comment. Both premium and bottom-shelf solar products come out of China, as well as a number of mid-range ones. The old motto goes ‘you get what you pay for’. We’ve had many a customer who has gone ahead with systems that use Chinese components and been happy with them. There may be more of a guarantee of quality from European brands, but with a bit of discrimination it is also quite possible to find quality components with a ‘Made in China’ label.
Comments are closed.
Helping Australians make a well-informed decision since 2008
Batteries with a 6.6kW solar system?
Hi Solar Choice,
Looking at getting solar and the more I do the more confusing it seems to be, no two quotes alike.
One I am favouring are quoting a 6.8Kw Canadian 340w 144 cell x 22 panels with Fronius 6kw phase inverter and Fronius Smart metre for full monitoring purposes Solar PV for $8800.00
Everyone else has quoted using a 5 kw inverter and I am advised while a bit more expensive it will in the long run give me more of a return on a cheaper electricity bill.
My quarterly bills are currently averaging out at $670.00
If you are able to offer any advise I would indeed be grateful.
Thank you Simon
Hi Simon,
Solar panel arrays are allowed to be oversized relative to the inverter capacity – so a 5kW inverter with 6kW worth of panels is relatively common these days. When you take this approach, your solar system will produce a bit more energy in the mornings and afternoon, but will flatline in the middle of the day, when the sun is at its brightest. The overall effect is that you get more energy out of a 6kW solar panel / 5kW inverter system than you would out of a 5kW panel / 5kW inverter system – especially during the times that you’re likely to use it (morning & arvo).
This approach is particularly attractive for two reasons: 1) Some electricity networks only allow up to 5kW of inverter capacity to be connected without extra red tape, and 2) 5kW inverters are very common and therefore often less expensive than other ‘niche’ sizes because of the amount of competition in this size range. So you might find a a good deal in a system that oversizes the panel array.
It sounds like the 6.8kW Canadian / 6kW Fronius inverter setup that you’re currently leaning towards is a decent quality system – on the ‘premium’ end of things. According to our pricing figures, a ‘premium’ 7kW solar system retails for about $1.20 per watt – or about $8,400 on average nationally (we don’t have specific pricing for 6kW systems, so I encourage you to check out the table and look for your nearest capital city). I also note that this price doesn’t include extras like monitoring, so that could explain the higher price you’re looking at (and also: some places have higher overall prices – especially VIC and TAS).
I hope this helps!
What is the rebate rate of the solar power installed 2 years ago?
It was 68 cents but we got a letter from the service prowider ( AGL ) it is 60 cents now. We changed from Origine because it paid only 66 cents…
Is there a better deal with any of other company?
Do you have a list I can select from?
Thanks a lot
Attila
Hi Attila,
I think you’re referring to feed-in tariffs as opposed to a rebates. Regardless the options available to you will depend on what state you live in. Unfortunately, we don’t have a comprehensive list of what’s on offer from energy providers as we help people get the best solar PV installation deal for them. I’d recommend you have a look at a comparison site for energy company’s.
As a rough guide, the base level in NSW two years ago was 60¢ per KWh, although energy retailers did offer various options to encourage people (like yourself) to switch. There is currently no mandatory feed-in tariff in NSW so switching to another energy provider may result in you loosing the 60¢ rate, the best on offer in NSW is now 8¢ per KWh! If you speak to AGL they may be able to tell you why the rate was dropped and their competitors may by able to advise as to whether you will still be eligible for the earlier Premium tariff.
Sorry we can’t be of more help, good luck!
Thank you for your independent assistance as there is so much information that I obviously don’t understand.
As I have had “my fingers burnt” with Chinese manufactured goods (they seem to provide cheap & only lasting 1/4 or 1/3 of previous products & so I don’t buy to throw out as I don’t like our disposable age !! Graeme
Graeme,
Thanks for the comment. Both premium and bottom-shelf solar products come out of China, as well as a number of mid-range ones. The old motto goes ‘you get what you pay for’. We’ve had many a customer who has gone ahead with systems that use Chinese components and been happy with them. There may be more of a guarantee of quality from European brands, but with a bit of discrimination it is also quite possible to find quality components with a ‘Made in China’ label.