6kW solar systems

6kW solar systems: Pricing, output, and returns

by Solar Choice Staff on 24 February, 2018

in Solar and Renewable Energy Policy,State Government solar feed-in tariffs,ACT,NSW,NT,QLD,SA,TAS,VIC,WA

6kW solar systems are becoming increasingly popular amongst Australian homes thanks to a number of factors, including their affordability and ample size. 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 in a 6kW solar system? How much area required?

A modern-day 6kW solar system using 250 watt (W) to 320W modules will consist of about 19-24 panels.

Each panel generally measures out to about 1.7m2, so the roof area required for a 6kW system will be about 33-40m2 – 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 solar systems

Are 6kW systems the new 5kW system?

Although your system may have 6kW worth of solar panels, don’t be surprised if the proposed inverter for your system is only 5kW. 5kW solar systems are also incredibly popular in Australia for a number of reasons (including the fact that that size is pre-approved for grid connection on basically every network in the country), which means that 5kW inverters are much more common to come across than 6kW ones. Many of the 6kW solar systems on the market are therefore ‘overclocked‘ systems with a 5kW inverter. This is perfectly legitimate within Clean Energy Council guidelines, with benefits such as greater solar energy yields in early morning and late afternoon – even if ‘peak’ production is clipped back to 6kW during the middle of the day.

Also see: Solar Choice’s 8-point Guide to Solar & Batteries (plus FAQs)

Check out our Home Solar & Battery Guide

How much does a 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. While we don’t specifically track 6kW systems, we do track 5kW pricing – historic pricing trends for which can be seen in the graph below:

Average 5kW solar system prices (per watt of capacity) in each Australian capital city, from August 2012 to early 2018. Historic 6kW system pricing trends should follow the same lines.

In Australia, the average retail price of a standard solar PV system installation of mid-range quality is a bit above $1 per watt, after federal government solar rebates are taken into account. This means that at the time of writing (Feb 2018), the cost of such a 6kW solar system is around $5,500-$7,500 – significantly less than what it would have been even just a few years ago.

The price of solar systems do, however, vary widely in the market. A more cost-competitive 6kW solar PV systems consisting of cheaper, low-end products will be cost less, while premium offerings will generally be pricier.

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How much energy will a 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 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 Metorology and PVWatts data.

Please note that these figures are indicative only and that we have endeavored 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.

North-facing 6kW solar system
Capital City Approx solar energy production
Adelaide 22-24kWh
Brisbane 23-24kWh
Canberra 22-25kWh
Darwin 27kWh
Hobart 17-20kWh
Melbourne 19-22kWh
Perth 24-26kWh
Sydney 20-23kWh
*Via PVWatts & Bureau of Meteorology

Batteries with a 6kW solar system?

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 5kW; a system of this size will generally provide plenty of surplus energy for storing. At slightly larger than 5kW, 6kW systems would also be a good size for batteries.

Further reading:

Is solar battery storage worth it in 2018?

How long is the payback period on a 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 6kW solar systems in a handful of Australian capital cities based on average prices as of February 2018. (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 returns for 6kW solar systems at average prices in select capital cities

(Assuming 30kWh electricity consumption/day)


(assumes 11c/kWh feed-in tariff, 25c/kWh retail rate)


(assumes 11c/kWh feed-in rate, 21c/kWh retail rate)

 $7,300  $6,700
 @ 20% self-consumption  @ 40% self-consumption @ 20% self-consumption @ 40% self-consumption
 ~6.7 year payback  ~5.5 year payback  ~5.8 year payback  ~4.9 year payback
 ~14% IRR ~18% IRR  ~16% IRR  ~20% IRR
 ~$1,050 annual savings  ~$1,300 annual savings  ~$1,100 annual savings  ~$1,300 annual savings

(assumes 11.3c/kWh feed-in tariff, 21c/kWh retail rate)


(assumes 7c/kWh feed-in rate, 27c/kWh retail rate)

$7,500 $5,500
@ 20% self-consumption @ 40% self-consumption @ 20% self-consumption @ 40% self-consumption
~7.8 year payback ~6.7 year payback ~5.4 year payback ~3.9 year payback
~11% IRR ~14% IRR ~18% IRR ~26% IRR
~$930 annual savings ~$1,170 annual savings ~$1,000 annual savings ~$1,400 annual savings

Solar Choice’s 8-point Guide to Solar & Batteries (plus FAQs)

Check out our Home Solar & Battery Guide

solar_choice_logo_finalReady to shop for solar & batteries? Compare quotes from installers in your area.

Since 2008, millions of people have accessed Solar Choice’s website to educate themselves about their solar prospects. We’ve also helped over 125,000 Australian households & businesses make an informed choice about selecting an installer with our free and impartial Quote Comparisons.

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© 2018 Solar Choice Pty Ltd


Attila Karasszon 20 September, 2012 at 1:15 am

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

Solar Choice 20 September, 2012 at 2:37 pm

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!

butler graeme 27 July, 2012 at 6:57 pm

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

admin 30 July, 2012 at 12:04 pm


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.

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