Solaray Energy is now called 1KOMMA5° Sydney and 1KOMMA5° Melbourne

The Price of a 15kW Solar Power System For Sydney In 2024

Thanks to record low prices and generous government incentives, it is now becoming common for a larger household to install a 15kW solar system. Let’s have a look at a few of the key numbers including the price of a 15kW solar power system, and the brands you should be looking at for a system of this size.
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Tom Sedgwick
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3 min

The Price Of A 15kW Solar Power System

The price of a fully installed 15kW solar power system in NSW has fallen dramatically in recent years, and government incentives are still available.

For larger solar systems we exclusively sell Smart Solar due to the performance and safety benefits over the older string inverter technology.

A 15kW Solar Power System starts at around $12,000 fully installed, with panels from Trina, a Sungrow 3-phase Inverter and a standard installation (ie. no cherry pickers etc).

It is important to remember that with solar panels you generally get what you pay for, and now that the return on investment is so good for a system of this size most of our customers choose top-of-the-range panels from manufacturers such as 1KOMMA5° and REC Solar. A 15kW solar system using 420W 1KOMMA5° panels and Enphase Microinverters costs around $20,000.

It is possible to find cheaper 15kW solar systems, however, this will typically require buying lower-quality panels manufactured in China and a cheap string inverter with much older technology. These budget solar systems often come without any after-sales support, or end up as a solar orphan.

For a larger system of this size, it is important to maximise reliability, output, and of course longevity, so spending more upfront will typically end up saving you a lot of money over the life of the system.

1KOMMA5° service full-replacement warranties and include full technical support. This gives our customers the peace of mind that if something goes wrong you will be looked after.

As a rough guide, a 15kW system can save you up to around $6,000 a year on your power bills, so even on the top-of-the-range systems, you can still see a return on your money in well under 5 years.

Of course, to save $1,500 on a quarterly bill you are going to need to use a lot of power during the daytime – as much as 80 kWh during the daytime over summer. This is why most of our customer now look at adding battery storage to their solar system, as they can store excess solar power to then use in the evening. If you are able to get the most out of your 15kW system, you could spend up to $20,000 on a top-of-the-range system and see a return on your investment in under 4 years!

A 15kw solar system will reduce your household’s CO2 emissions by up to around 300,000 kg over 15 years.

How much will a 15kW solar system save me?

The potential savings from a 15kW solar system depend on how much solar power you are able to use in the home at the time of generation. You will typically save around 22 to 30 cents a kWh (depending on how much you pay for your power), and depending on your retailer, you will be paid around 5-10 cents a kWh for the power you send back to the grid. A 15kW solar system can save you up to around $1200 to $1600 per quarterly bill.

More information is available here: How Solar Power Reduces Your Power Bill

Number of solar panels for a 15kW System

The larger the system, the more important it is to buy quality panels to ensure you maximise reliability, increased output in all weather conditions and the longevity of the system.

The other consideration is roof space. By installing high-efficiency panels, we can use 36 x 4155W panels or 37 x 405W panels.

15kW Micro Inverter System

1KOMMA5° is the largest and most experienced installer of Enphase Micro Inverter systems in NSW, and our system design team are experts at putting together a professional solar array that will maximise solar output in all conditions.

enphase shade imahge

The main benefit of microinverters is that each panel is independent of the others, making it possible to design an array across different orientations and at different angles. A common panel layout is to have some panels facing north, and the others west to spread the output of solar power across the day, making it easier to use more of the solar power as it is generated. Having panels west is also advantageous if you are on time-of-use billing, where households typically pay over 50c per kWh between 2 pm and 8 pm for power.

On larger residential systems, the panels in the middle of the array can get quite hot during summer as airflow under the panels is less than ideal. When panels get too hot, the output can be significantly reduced. Because of this, we recommend using microinverter technology and in fact, over 80% of our systems now include this technology. Find out all you need to know about Enphase: 10 key benefits of microinverter systems.

20KW Solar Power Case Study

The output of a 15kW Solar System

According to the Clean Energy Council guidelines, a 15kW solar system in Sydney facing north will produce an average of around 60kWh a day, outputting more power in summer and less in winter. We have found that this guideline is a conservative estimate and that by using the top brands you can get considerably more out of our system, for example, our Enphase systems give our customers on average 110% of expected output.

On a sunny day in summer, a 15kW system will often give our customers over 90 kWh of power. Because this can be too much power for many households, we often recommend splitting the panel array across two orientations to distribute the output of power across the day, and to consider battery storage so that any excess solar power can then be used during the evening.

15kW Solar System Output

A 15kW Solar System – The Key Numbers

System Size15kW Solar Power System
Number of panels36 x 420W panels
OutputAround 60kWh a day on average (see the graph above)
Potential savings$1200-$1600 a quarter depending on your cost of power and how much solar power you use as it is generated
Average payback period3 to 6 years
15kW solar system costFrom around $12,000 to $20,000 depending on the panel and inverter used
RepaymentsContact us for more details. Terms of 3-7 years available
Suited toLarger homes or businesses using on average around 60kWh during the daytime (or over 24 hours with battery storage)

Request for a solar and home battery storage quote today to see how much you can save!

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