6.6kW Solar System: Price, ROI, and Output

6kW solar systems, or more commonly known as 6.6kW solar systems, are gaining popularity in Australian households due to several factors. These include their cost-effectiveness, generous capacity, and ease of approval for grid connection. This article offers a comprehensive overview of nearly everything you need to consider when contemplating a 6kW solar system for your home, covering aspects such as pricing, energy output, and their viability as an investment.

What is the panel count and area requirement for a 6.6kW solar system?

A contemporary 6.6kW solar system, utilizing modules with a power range of 330 to 400 watts, typically comprises approximately 17 to 20 solar panels. This quantity has notably decreased in the past decade.

Each panel typically covers an area of 1.7m², so the roof space needed for a 6.6kW system is around 34-38m² — potentially more, depending on your roof layout and whether you opt for tilt frames (which require more spacing than flush-mounted panels on the roof).

Is the 6.6kW system replacing the 5kW system?

Despite having 6.6kW of solar panels in your system, it’s common for the recommended inverter to be only 5kW. 5kW solar systems are widely favored in Australia for various reasons, including their pre-approval for grid connection across most networks in the country. Consequently, 5kW inverters are more prevalent than their 6kW counterparts in the market. Many 6.6kW solar systems available are, therefore, ‘overclocked’ configurations equipped with a 5kW inverter.

Under the Clean Energy Council guidelines, a 5kW inverter can be overclocked by a maximum of 33% to reach 6.6kW. However, it falls short of reaching 7kW, requiring a larger inverter for such capacity. This setup provides advantages like increased solar energy yields in the early morning and late afternoon, even if the ‘peak’ production is limited to 5kW during the midday period.

What is the expected energy output of a 6.6kW solar system?

The actual power generated by a 6.6kW solar power system can vary based on several factors, including:

  • Location and local climate
  • Tilt angle and orientation of the solar panels
  • Presence of shading on the panels
  • Performance of individual components, primarily the panels and inverter

The solar system’s location is a key factor influencing energy yields, as sunlight exposure directly impacts the system’s output. The table below offers approximate estimates of the energy production from a 6.6kW solar system, relying on data from the Bureau of Meteorology and PVWatts.

It’s important to note that these figures are approximate, and conservative estimates have been employed, assuming a system efficiency rate of 75%. Additionally, these figures represent annual averages; in reality, energy yields will be higher in summer and lower in winter.


Energy Output from a 6.6kW Solar System

Capital City Approx. Solar Energy Production* (per day)
                           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

*Approximate values; actual energy production may vary based on factors such as location, climate, orientation, shading, and component performance.


6.6kw Solar System with Battery

An increasing number of households are contemplating battery storage when acquiring a solar system. The minimum size we typically suggest for installation, whether you plan to incorporate batteries immediately or in the future, is 5kW. Such a system is generally sufficient to generate surplus energy for storage. Additionally, 6kW systems, slightly larger than 5kW, are also well-suited for integrating with batteries.


ROI On 6.6kw Solar System

The key metric for evaluating a solar panel system’s performance, for most consumers, is the payback period. This period represents the number of years it takes for the system to recoup its cost through energy bill savings and feed-in tariff credits.

The table below illustrates estimated payback periods, internal rate of return (IRR), and first-year savings for 6.6kW solar systems in several Australian capital cities. These figures are based on average prices as of July 2023. (Please note that these outputs are generated using our Solar System Payback & ROI Estimator tool, and we encourage you to use your own numbers for a personalized assessment.)

It’s essential to consider that returns may vary, potentially being more favorable for systems with lower price points or higher levels of solar self-consumption. However, caution is advised in selecting products and companies, as some seemingly attractive deals may be too good to be true.


Final Thoughts

The popularity of 6.6kW solar systems in Australia is driven by factors like affordability and grid connection ease. Key considerations include panel count, inverter capacity, and potential battery integration. Geographical location significantly influences energy output, and the payback period is a crucial economic metric. Regional variations underscore the importance of personalized assessments. In deciding on a 6.6kW solar system, careful consideration and staying informed about technological advancements and policies are essential for making a sustainable and cost-effective choice.

At Ultimate Solar Energy, we make your decision-making process so simple. We design customized solutions based on your requirements, using only the most premium products.

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