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Your Complete Guide to A 15kW Solar System in Sydney in 2026

With solar energy becoming more affordable and government rebates in place, there's no better time to switch. Especially for larger households, a 15kW solar system can significantly reduce your electricity bills. This guide will explore everything you need to know about installing a 15kW solar system in Sydney this year.

Key Takeaways:

  • Invest in Premium Solar for Long-Term Value - A basic 15kW solar system typically starts at around $18,000, with premium systems priced higher. While budget options exist, choosing high-quality components can deliver greater efficiency, a longer system lifespan, and reduced maintenance over time..

  • Lower Your Power Bills with Solar - A 15kW solar system can slash your electricity bills by $1,200 to $1,800 per quarter, depending on your energy usage. By running appliances during the day and adding a battery to store excess power, you can maximise your savings and rely less on the grid.

  • More Power, Fewer Panels - Choosing high-efficiency panels enables you to install fewer panels without overcrowding your roof. With 34 x 450W panels, you can reach 15kW while using less roof space.

15kW Solar System Price in Sydney

For larger solar systems, we exclusively sell smart solar due to their advanced features and safety benefits:

  • A basic 15kW solar system starts from around $18,000. This includes Trina panels, a Sungrow inverter, and standard installation.

  • For top-tier performance and long-term value, we recommend upgrading to premium components like 1KOMMA5° panels and Enphase microinverters. While this does increase the upfront cost, it delivers greater efficiency, flexibility, and a stronger return on your investment.

While budget systems might seem tempting, remember – you often get what you pay for. Here's why investing in quality makes sense:

  1. Lower-quality panels are more prone to performance issues and may require frequent repairs.

  2. Top-tier panels are built to last for decades, maximising your return on investment.

  3. High-efficiency panels convert more sunlight into usable energy, boosting your power generation.

By spending a bit more upfront on a quality system, you'll likely save more money in the long run due to increased efficiency, reliability, and a longer lifespan.

How Much Will a 15kW Solar Power System Save Me?

A 15kW system can significantly slash your electricity bills – potentially saving you up to $1,200 to $1,800 per quarter. But, these savings depend on your daytime energy usage. To maximise your savings, try to use more power when your system is generating the most, which is typically during the day. Here are some ways to boost your self-consumption:

  • Shift your energy use: Run appliances like dishwashers and washing machines during the day when your solar system is producing power.

  • Time-of-use billing: If you have this billing structure, you'll pay more for peak usage times, which often coincide with afternoon sun. A 15kW system can help you generate power during these times to offset these higher costs.

  • Solar battery storage: This allows you to store excess solar energy during the day and use it at night or during peak billing periods.

These are just some of the ways how to reduce your power bills. To find out more, here's a helpful resource that can help: How Solar Power Reduces Your Power Bill

a single-story brick house with solar panels on the roof

How Many Solar Panels Are Needed For A 15kW Solar System?

The number of panels depends on their efficiency. High-efficiency panels allow for fewer panels while achieving the desired output. To generate a 15kW system, we can use 36 high-efficiency 425W panels or 34 high-efficiency 440W panels.

15kW Microinverter Solar System

Enphase microinverter performance with shading issues

1KOMMA5° is the largest and most experienced installer of Enphase microinverter 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.

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.

The Output of a 15kW Solar System in Sydney

A 15kW system facing north in Sydney can generate up to 60kWh daily. However, using high-quality systems with top-tier components often outperforms expectations.

On a sunny summer day, you could even generate over 90kWh! This excess solar energy can be used to power your home during the evening or fed back into the grid for a credit on your electricity bill.

With a system this powerful, you might want to consider ways to utilise all that solar energy. Start by installing panels across multiple roof sections to spread power generation throughout the day, better matching your energy use patterns. This can be particularly beneficial if your roof isn't perfectly north-facing.

See if you can add battery storage. Batteries are becoming increasingly affordable and can significantly enhance the benefits of your solar power system.

15kW solar panel system estimated average daily energy output by month

A 15kW Solar System: The Key Numbers You Need To Know

System Size15kW Solar Power System
Number of Panels34 x 450W panels
Outputaround 60kWh a day on average (see the graph above)
Potential Savings$1200-$1800 a quarter depending on your cost of power and how much solar power you use as it is generated
Average Payback Period2.5 to 4 years
15kW Solar System Coststarts from $18,000 and may go up 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)

More Helpful Articles:

Solar Panel Installation – What Else to Consider

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Need more information?

Head over to the 1KOMMA5° blog for more helpful tips and other important guides on everything solar, from inverters, panels and batteries to how to make the most of your investment for years to come.