6kW & 6.6kW Solar Systems: Costs, Output, and Returns

6kW or now extra generally seen 6.6kW solar techniques have gotten more and more fashionable amongst Australian properties due to a lot of components, together with their affordability, ample dimension & ease of approval with regards to connecting to the grid. This article gives an summary of (virtually) every little thing it’s worthwhile to know when you’re contemplating a 6kW solar system on your family, together with pricing, energy yields and their attractiveness as an funding.

How many panels in a 6.6kW solar system? How a lot space required?

A contemporary-day 6.6kW solar system utilizing 330 watt (W) to 400W modules will include about 17-20 solar panels. This quantity has decreased so much during the last decade.

Each panel typically measures out to 1.7m2, so the roof space required for a 6.6kW system can be about 34-38m2 – or probably extra relying on how your roof is laid out and whether or not you require tilt frames (which should be spaced out greater than panels mounted flush on the roof).

An vital word about inverters for 6kW/6.6kW solar techniques

Are 6.6kW techniques the brand new 5kW system?

Although your system could have 6.6kW value of solar panels, don’t be stunned if the proposed inverter on your system is barely 5kW. 5kW solar techniques are additionally extremely fashionable in Australia for a lot of causes (together with the truth that that dimension is pre-approved for grid connection on mainly each community within the nation), which signifies that 5kW inverters are rather more frequent to return throughout than 6kW ones. Many of the 6.6kW solar techniques available on the market are subsequently ‘overclocked‘ techniques with a 5kW inverter.

A 5kW inverter could be overclocked by a most of 33% beneath the Clean Energy Council pointers to six.6kW however can’t fairly get to 7kW which might require a bigger inverter. This affords advantages equivalent to higher solar energy yields in early morning and late afternoon – even when ‘peak’ manufacturing is clipped again to 5kW throughout the center of the day.

How a lot does a 6.6kW solar system price?

Solar Choice has been conserving monitor of residential solar system costs since August 2012 with our month-to-month Solar PV Price Index. Based on this knowledge we will advise that the common 6.6kW solar system will price round $0.94 per watt or $5,830 after the federal STC rebate has been deducted as of March 2022 .

The value of solar techniques do, nevertheless, differ extensively available in the market. A extra cost-competitive 6.6kW solar PV techniques consisting of cheaper, low-end merchandise will price much less, whereas premium choices will typically be pricier.

The beneath graph reveals the value historical past of the final couple of years. You can see the pricing has remained comparatively flat nevertheless there are some variations relying in your location in Australia.

6.6kW Solar system average costs by state - Solar Choice price index

Average 6.6kW solar system costs (per watt of solar panel capability) in every Australian capital metropolis, from August 2012 to the tip of 2021. 


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How a lot energy will a 6.6kW solar system produce?

Depending on a lot of components, the precise power output of a 6kW solar power system will differ. These variables embody:

  • Location and native local weather
  • Orientation and tilt angle of the solar panel array
  • Whether there may be any shade forged on the panels
  • The efficiency of the person parts (primarily the panels and inverter)

Location is likely one of the primary determinants of solar system energy yields, as the quantity of sunshine falling on a solar system’s solar panels immediately impacts the system’s output. The desk beneath gives tough approximations for a way a lot energy a 6kW solar system will produce, primarily based on Bureau of Metorology and PVWatts knowledge.

Please word that these figures are indicative solely and that we’ve got endeavored to be conservative in our estimates, utilizing a system effectivity fee of 75%. Also word that these figures are annual averages – in actuality, energy yields can be increased in the summertime and decrease within the winter.

North Facing 6.6kW Solar System
Capital City Approx Solar Energy Production* (per day)
Adelaide 24-26 kWh
Brisbane 25-27 kWh
Canberra 24-27 kWh
Darwin 28-30 kWh
Hobart 19-22 kWh
Melbourne 21-24 kWh
Perth 26-28 kWh
Sydney 22-25 kWh

* Estimates generated utilizing Burea of Meterology historic climate knowledge and PVsyst software program


Batteries with a 6.6kW solar system?

More and extra households have battery storage in thoughts once they buy a solar system. The smallest dimension we typically suggest you put in when you’re contemplating batteries both now or sooner or later is 5kW; a system of this dimension will typically present loads of surplus energy for storing. At barely bigger than 5kW, 6kW techniques would even be a superb dimension for batteries.

Further studying:

Is solar battery storage value it?


How lengthy is the payback interval on a 6.6kW solar system?

The benchmark by which most solar buyers measure their panel’s efficiency is the payback interval – the variety of years that the system will take to ‘pay for itself in energy invoice financial savings & feed-in tariff credit.

The desk beneath reveals indicative payback durations, ‘internal rate of return’ (IRR) and annual financial savings within the first yr for six.6kW solar techniques in a handful of Australian capital cities primarily based on common costs as of March 2022. (Note that these are outputs from our Solar System Payback & ROI Estimator software – which we encourage you to discover with your personal numbers.)

Keep in thoughts that returns could also be higher for techniques whose value factors are decrease, or when you obtain a better degree of solar self-consumption. But even be conscious that you just’ll need to be selective concerning the merchandise and firms that you just think about – some offers are too good to be true.

Indicative payback durations for six.6kW solar techniques 

6.6kW System Cost Electricity Price Feed in Rate Self Consumption Rate IRR Annual Savings Payback Period (Years)
Sydney $5,170 25c 5c 30% 19% $977 5.2
60% 32% $1,593 3.2
Brisbane $5,170 18c 5c 30% 15% $817 6.2
60% 24% $1,223 4.1
Melbourne $4,980 27.5c 6c 30% 22% $1,064 4.6
60% 36% $1,728 2.9
Perth $4,380 28.8c 7c 30% 30% $1,272 3.4
60% 46% $1,948 2.2
Adelaide $4,940 31c 7c 30% 26% $1,282 3.8
60% 42% $2,024 2.4
Hobart $6,710 27c 8.5c 30% 16% $1,101 5.9
60% 26% $1,684 3.9
Canberra $4,960 20c 7c 30% 19% $946 5.1
60% 28% $1,359 3.6
Darwin $8,970 26c 8c 30% 14% $1,321 6.6
60% 22% $1,887 4.6


  • Average day by day energy use = 25 kWh
  • 6.6kW System price is the typical value from Solar Choice’s value index for a totally put in turnkey system
  • Excludes state-based solar grants / rebates (e.g. Solar Victoria rebate)

Calculate your personal solar payback interval utilizing Solar Choice’s free payback calculator.



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© 2019 Solar Choice Pty Ltd

Jeff SykesJeff Sykes

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