6kW Solar System Cost

Updated: April 27, 2021

6kW solar systems (or 6.6kW to be exact) are by far the most common solar system size. They are great for most average Australian homes

6kw solar systems cost $5,240 on average. Due to different brands, they do range between $4,210 and $6,600.

There are a few things you need to know before you buys so lets go through them now.

6kW Solar SystemPrice
National Average$5,240
Low Estimate$4,200
High Estimate$6,600
State6kW Price
New South Wales$5,166
Aust. Capital Territory$5,810
South Australia$5,320
Western Australia$4,210
National Average$5,240

How Much Power Will A 6kwh System Produce?

Energy outputs from solar systems tend to vary depending on the location they are installed. On average, a 6kwh solar system should produce at least 25Kwh in favorable weather. However, 6Kwh solar outputs are best estimated by location using climate information for solar energy from the Australian Bureau of Meteorology’s datasheets and solar vendor data as follows:

City/LocationEstimated 6Kw solar daily energy output
Canberra and surrounding areas 25.24Kwh
Adelaide and surrounding areas25.66Kwh
Brisbane and surrounding areas27.36Kwh
Melbourne and surrounding areas 21.95Kwh
Perth and surrounding areas29.1Kwh
Sydney and surrounding areas25.6Kwh
Solar panel orientation and tilt

The reason for the different figures based on location is primarily associated with daily solar radiation levels. However, other factors do affect individual solar outputs, such as:

Panel orientation and tilt– Solar panel orientation and tilt will affect how much power a system can generate. It’s, therefore, important to have enough space on the correct side of your roof for the panels.

Different regions may have varying panel tilt and orientation requirements based on solar radiation data.  That said, you don’t have to worry about this particular requirement. The solar company will most likely conduct their assessment and place the solar panels at an optimal position for maximum yield.

Solar system quality– Solar panel systems are not the same in terms of quality and efficiency. For instance, a high-quality smart energy solar kit would have slightly higher yields than a lower quality standard kit. Additionally, most solar systems usually come with an output tolerance of plus or minus two units of their watt rating.

Inverter setup and efficiency- Sometimes, the inverter might affect how much energy you get from a solar system. Your installer may suggest that you get a lower-wattage inverter to overclock the system and optimize solar performance.

Shading– Trees and large buildings blocking direct sun rays to your residence will affect how much power you can generate with your daily solar output. Talk to the solar installer on ways you can mitigate any shading issues to get the best out of your solar system.

Panel Maintenance – over time, dust, debris, and other foreign objects will accumulate on your solar panels. Proper solar panel maintenance is, therefore, a contributing factor to solar system outputs regardless of the rating or radiation levels.

Note: Too much dirt and debris will reduce the average solar production by a small margin, while physical damage such as cracks will have a significant impact.

Ambient temperature– High temperatures hurt solar panel performance. Depending on installation type and panel temperature coefficients, you may get varying solar outputs when temperatures get to certain levels.  It’s therefore important to explore the prevailing temperatures in your location and seek some advice from the installer on the best installation type for optimal performance.

Loss– As with most electrical connections, there will be a negligible loss in the DC and AC cabling that will affect your terminal solar output. This varies from installation to installation based on cabling length, interference, and quality.

6kWh solar system infographic cost

How Many Panels Are Needed?

A typical 6kw solar system will require twenty (20) solar panels, each measuring 1m by 1.6m.

However, panel size and the number of panels may vary from manufacturer to manufacturer. Some manufacturers do manage to make solar panels with higher outputs and therefore needing fewer panels for a given output rating.

Going by the above estimates, you will need at least 40 meters squared space+/- 5 on your roof to install the solar kit.

6kW Average Yearly Savings

6kw Sytem Size Average Yearly Savings700x414

How Do I Know If The 6kwh System Is the Right Size for Me?

The primary criterion to use when selecting a solar system has to be your current average daytime power consumption. Ideally, a standard residential solar kit should be able to provide enough daytime power consumption to cover the installation costs in a good time (payback period). Some other factors you should use to know if a 6kw system is right for you might include:

Your Household Energy Consumption

Some people prefer to have as much renewable energy as they can afford to reduce their electrical bills and contribute to the green initiative. If you fall into this category and have low to moderate daily power consumption, then a 6Kw solar system or higher could be the best for you. Keep in mind that the higher you go, the bigger the discount you get courtesy of the Australian STC solar rebate system.

A 6kw system is perfect for you if you have higher than average daily energy consumption needs. Below is a breakdown of common appliances and other electrical things you could run with a 6kw system. Keep in mind that these are just estimates, and solar output may vary according to weather conditions in your location.

A 6kw solar system operating at its peak will power:

Number of Units (Electrical equipmentVisual representation
12, 32 Inch Tv sets
About 572 LED lightbulbs
About five small water pumps

From the above table, you can see that a 6kw solar system can, at peak performance power, power a large home with above-average power consumption.  These are estimates of what a typical 6kw solar is meant to deliver at peak conditions. You may have very different outputs based on location weather and other factors affecting daily solar production.


Can you afford a 6Kw system? If yes, does it make sense to you based on your daily consumption? If you can make sense of the figures without factoring in the feed-in tariffs, then you are good to go. As mentioned earlier, installing a solar system whose output you can use is more attractive in terms of the payback periods.


If you live in territories with above-average all-year-round sun radiation, a higher wattage solar system might make a lot of sense. The favorable weather will not only make the solar system cheaper to install, but you will have better returns with surplus output from your solar system.

As an example, if you live in Brisbane and average about 10Kwh per day for normal consumption, you could yield the extra 17Kwh to the grid and benefit from the feed-in tariffs at 8c per Kwh. Though small, these payments will go towards recouping the installation charges.

What Is the STC On A 6 Kwh System?

Small-scale certificates offered for the 6kw solar system vary from region to region as specified by the Australian Clean energy and other industry stakeholders. At the same time, the deeming period (time before the STC solar rebate systems are wound up in 2030) will determine the value of the STC rebate you can get from a 6kwh system.

Suppose you were to buy and install a 6Kwh solar system in 2020? How many STCs would you get to go towards your point of sale discount?

Here are some estimates generated from the Clean Energy Authority’s system as of June 2020:

City/ RegionZoneNumber of STCs for 6Kwh Solar installs (11 years to 2030)
Alice Springs2107
Western Shore- South Tasmania478

As you can see from the estimates above, the areas presumed to have the highest and longest solar radiation will receive more STCs.  After getting the number of STCs for your 6kwh solar system, you can then multiply them with the current trading value to get the exact figure in Aussie dollars you will get off the purchase price.

For instance, as of the time of publishing this guide, the current trading value based on the latest trading numbers was $39.50. This means a consumer in Townsville would get $4,215 off their solar purchase courtesy of the STC solar rebate scheme.

Will I Need A 6Kwh Or A 6.6Kwh System?

Many people find it hard to choose between the overly popular 6.6Kwh and 6Kwh system. Personal preferences aside, the 6.6Kwhz solar system might be a more sensible option for a number of reasons such as:

  • There is little price difference in final pricing, including installation for both systems. This even when the 6.6Kwh solar kit provides an extra 0.600Kwh to the mix.
  • More STCs– For reasons best known to the regulators, going for the slightly bigger 6.6Kwh system will give you more STCs (quite a margin between them). For instance, a consumer buying a 6.6Kwh system in Western Shore, Tasmania, will receive 86 STCs. In contrast, the same consumer would receive 78 STCs for a 6Kwh system.
  • Almost similar panel count– Again, there is not much difference in panel count between a 6.6Kwh solar kit and a 6Kwh Kit. Some vendors will sell both systems with a maximum of 20 solar panels, albeit with different rated output.

That said, going for a 6Kwh system may make a lot of sense for many reasons, such as your power consumption and payback period. The 6Kwh solar system has a slightly shorter payback time than its close counterpart. However, it’s also important to note that payback times depend on your energy consumption numbers, such as the ratio between the solar energy consumed vs. that coming from the grid.

What Is the Price with A Battery?

Standard solar kits don’t come with battery storage unless you purchase one with an embedded battery. If you are planning on storing surplus energy instead of feeding it back to the grid, a battery with nominal capacity ranging between 5kw- 6.5Kw would be the most logical option for a hybrid (grid-connected plus battery) 6Kwh solar system.

A good quality 6.5 battery goes for about $6,00.00 in Australia. Add this to the solar kit with STC discount applied, and you are looking at approximately $10,000 at the low end. Of course, there are many solar batteries out there to choose from, so feel free to shop around.

Also, do note that solar batteries aren’t covered under the STC solar rebate scheme unless for embedded ones hence the significantly higher costs.  6Kw solar kits that come with embedded batteries usually cost anything between $7000 to $12,000 depending on battery capacity and type.

Will Having A Battery Take Me Totally Off-Grid?

You can choose to go totally off-grid if you wanted to, but that would require a higher capacity battery pack -probably higher than 6.4Kw – to have enough backup energy for nighttime usage. However, a more accurate approach to this problem requires you to assess your current options as follows:

  • What is your total day and night time consumption like?
  • Will the 6Kw solar system provide enough power plus a backup to be stored for nighttime and overcast days?
  • Does the purchased solar kit have an off-grid option? – Off-grid solar installations are generally more complex and expensive. Pricing has to be personalized because backup and installation requirements vary from one installation to the next.
  • How many batteries can you afford? – As mentioned earlier, solar batteries are still quite expensive in Australia. In fact, you could find that an off-grid battery pack costs almost double the price of the entire solar installation because of the subsidies included.
  • How long will you need the backup storage to stay off-grid? – While typical 6kw solar kits can last for decades, backup systems such as batteries have a significantly shorter lifespan determined by the number of discharge/charge cycles.

Going off-grid is definitely a worthy venture if you have the funds. In most cases, an off-grid solar system would make sense to people with remote homes, mobile homes, or caravans because they can’t hook to the grid.


Short answer? No. The authorities require that a certified and accredited solar installer does the site survey and installation following the set guidelines. According to the Clean Energy Authority, DIY solar installations are not allowed because of the safety and quality requirements set out. This is especially important in conventional grid-connected solar systems where a faulty installation would affect everyone on the grid.

Also, be advised that going the DIY route would potentially void your warranties, rebates, feed-in tariffs, and other permits usually bundled with a solar kit.  With this in mind, the safest approach would be to let the solar vendor of your choice do the assessment, installation, and even maintenance.

You will need to contact some local solar installation companies to get prices for equipment supply and installation.

An inverter is required for any kind of solar system to convert DC from the solar panels to usable AC commonly used in electrical equipment and also fed back to the grid. For reference, a 5.5Kw inverter would suffice for a 6kwh solar system, although most solar kits do come with an inverter of the vendor’s choosing. You also need an inverter to charge any backup batteries you might be using.

You can save up to $500 per billing cycle depending on how much solar energy you can utilize; solar yield and feed-in tariffs in case of a surplus. Lifetime savings could go up to $50,000, provided you make use of the solar system throughout the period. For homeowners looking to cut or eliminate their electrical bills, a 6kw solar system is definitely worth every coin spent, plus it pays for itself in the long run.

Feed-in tariffs are payments advanced to solar owners who feed their surplus energy to the grid. Average feed-in tariff rates in Australia range from 8c/Kwh to 9c/Kwh. You’ll need a grid-connected solar to benefit from any feed-in tariff system that is available in your area. These tariffs may not be worth much, but they do help reduce your payback periods and system sizing.

From a saving perspective and with long-term goals, getting a battery to store surplus energy is more logical. The more energy you can consume from your solar system, the better. Using the grid as a buffer means selling your surplus at meager rates if compared to what you would pay on regular electrical bills. However, batteries don’t come cheap, so prepare to have an extended payback period and higher initial investment.

The typical payback period for a grid-connected 6kw system is estimated at 2.4 to 3.5 years, depending on several factors such as yearly output, rebates, gains from feed-in tariffs, and utilization.

Purchasing and installing a 6kwh solar system is worth it whichever way you look at it. From low pricing due to government incentives to monthly savings. Short payback periods to reliable backup power. All these factors make solar installs for Aussie homesteads quite attractive.

Ben McInerney head shotAuthor: Ben McInerney is a renewable energy enthusiast with the goal of helping more Australians understand solar systems to make the best choice before they purchase. Having an accredited solar installer in the family helps give Ben access to the correct information, which allows him to break it down and make it easily understandable to the average homeowner.