6.6kW Solar System Cost

Updated: October 16, 2023

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

A 6.6kw solar system will cost around $6,893. Different brands, quality, and installers play a role in solar panel prices.

The state you live in and the amount of rebate you are eligible for also play a factor.

6.6kW Solar SystemPrice
National Average$6,893
Low Estimate$6,495
High Estimate$7,412

6kW Average Yearly Savings

6kw Sytem Size Average Yearly Savings700x414

How Many Panels Are Needed?

A typical 6kw solar system will require 18 x 370W solar panels, each measuring 1m by 1.7m.

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 need fewer panels for a given output rating. You will need to check your north-facing roof space to see which option is best for you.

Going by the above estimates, you will need around 31 m2 of north-facing roof space.

Solar rebate for a 6.6kW system

The solar rebate you receive for a 6.6kW solar system will depend on the state you live in. Different states are in different STC zones which allow different rebate amount.

Zones: 1, 2, 3
States: NSW, QLD, WA, SA, NT, ACT
STC’s: 72
Rebate: $2,873

Zones: 4
States: VIC, TAS
STC’s: 62
Rebate: $2,474

STC Zone ma in Australia

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

When selecting a solar panel system it’s all about the average Australian reducing their power bills by 90% or more. Ideally, a standard single-phase 6kw system should cover you if you consume an average of 26kWh of power per day. You will need to check your power consumption over the last 12 months.

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 use less than 26kWh of power per day. 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 city.

Factors to consider when looking at a 6.6kW system


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 lots of year-round sunshine, 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 consume 22kWh of power per day, you would feed about 17Kwh to the grid and benefit from the feed-in tariffs at 8c per Kwh. This is because 70% of household power is consumed at night, but all solar power is produced through the day.

Roof space

This actually needs to be the first thing you check. Having enough North facing roof space is paramount for this all to work. IN some cases you can get away with it facing on slightly different angles, but you will need to consult a professional solar installer first before committing to anything.

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

Solar system quality – Good 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 power 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 power system. 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 output by a small margin, while physical damage such as cracks will have a significant impact.

Ambient temperature – High temperatures hurt solar power system 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 single-phase 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.

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

Many people find it hard to choose between the overly popular 6.6Kwh and a 6kW solar system. Personal preferences aside, the 6.6kW solar systems 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 is even when the 6.6Kw solar system 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 6.6Kw solar system in Western Shore, Tasmania, will receive 62 STCs. In contrast, the same consumer would receive 56 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 outputs.

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.

Will I Need an Inverter?

An inverter is required for any kind of solar power system to convert DC from the solar panels to usable AC commonly used in electrical equipment. The great news is a 5Kw inverter would suffice for a 6.6kw solar systems. This means the price will be cheaper as you won’t have to pony up for a larger inverter. This is because a 5kw inverter can be “over-clocked” quite safely to handle 6kw solar system power loads.

Why not a 6kW inverter?

Well in short it is cheaper. A 6kw inverter is about 30% more expensive. The 5kW inverter has the capacity to do the job easily, and you save money in the process. It’s cheap, so it’s a win-win.

What Is the STC On A 6 Kwh System?

City/ RegionZoneNumber of STCs for 6Kwh Solar installs (11 years to 2030)
Alice Springs273

What Is the Price with A Battery?

If you plan on storing surplus energy instead of feeding it back to your energy supplier, a battery backup for your 6kW system will do the trick. With a nominal capacity ranging between 14kW- 18kW would be the most logical option for a hybrid 6Kwh solar system.

A good quality Tesla Powerwall battery goes for about $12,500 in Australia. This should be enough storage for your needs. 

Depending on your state, you may also be eligible for a solar battery rebate, so be sure to apply if applicable.


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.

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 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 power system throughout the period. For homeowners looking to cut or eliminate their electricity bill, 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. Feed-in tariff rates in Australia range from 8c/Kwh to 9c/Kwh. These tariffs may not be worth much, but they do help reduce your payback periods and system sizing.

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.