A 6.6kW solar system remains one of the most popular residential solar choices in Australia. With power prices at all-time highs and solar rebates still available, more homeowners are asking the same question: How much will a 6.6kW solar system save me?

In this guide, we break down real savings, output by state, system costs, government rebates, and how many panels a 6.6kW system typically includes. We also compare similar system sizes such as the 6kW solar system and larger options like a 10kW solar system so homeowners can make an informed decision.

What Is a 6.6kW Solar System?

A 6.6kW solar system consists of solar panels and an inverter with a total generation capacity of 6.6 kilowatts. It’s ideal for households using 15–25 kWh per day, typically families of 3–5 people.

It is often chosen over a 5kW solar system because the additional capacity provides significantly higher daily savings for only a small cost increase.

A standard setup includes:

• 15–18 solar panels
  
  
• A 5kW inverter
  
  
• Roof space of approximately 25–35 m²
  
  
• Grid connection with optional battery storage

How Many Panels Are in a 6.6kW Solar System?

The number of panels depends on panel wattage.

Typical Panel Calculations

• 370W panels → around 18 panels
  
  
• 440W panels → around 15 panels
  
  

Most modern Australian homes use higher-efficiency panels, reducing roof space requirements while increasing overall generation.

The total roof space required ranges from 25 to 35 square metres, depending on orientation and shading.

How Much Power Does a 6.6kW Solar System Produce?

The output of a 6.6kW solar system varies by state due to weather and sunlight exposure.

Average Daily Output by State

• Queensland: 24–28 kWh/day
  
  
• New South Wales: 22–26 kWh/day
  
  
• Victoria: 18–22 kWh/day
  
  
• South Australia: 22–27 kWh/day
  
  
• Western Australia: 23–28 kWh/day
  
  
• Tasmania: 15–19 kWh/day
  
  

Your system’s performance depends on:

• Roof direction (north-facing produces the most energy)
  
  
• Shading and tree cover
  
  
• Panel quality
  
  
• Inverter efficiency
  
  
• Local climate
  
  
• Temperature and weather trends
  
  

A well-installed system from a professional provider can ensure maximum output year-round.

How Much Will a 6.6kW Solar System Save Me in Australia?

Savings vary by household consumption, local electricity rates, and how much solar energy you use during the day.

Average Annual Savings

Most households can expect $1,500 to $2,400 in yearly savings, depending on state and energy usage patterns.

Breakdown of Savings

Savings come from two sources:

1. Self-consumption
   Power used directly from solar instead of buying from the grid
   
   
2. Feed-in Tariffs (FITs)
   Excess electricity exported back to the grid
   
   

Example for an average NSW family:

• Daily generation: 22 kWh
  
  
• Self-consumption: 12 kWh
  
  
• Export: 10 kWh
  
  
• Savings from self-use: 12 kWh × $0.34 = $4.08/day
  
  
• Savings from FIT: 10 kWh × $0.06 = $0.60/day
  
  
• Total daily savings: $4.68/day
  
  
• Annual savings: approx $1,700/year
  
  

A household with higher daytime usage can save over $2,000 per year.

Cost of a 6.6kW Solar System in Australia (2025 Prices)

As of 2025, the average cost of a 6.6kW solar system ranges from:

$4,500 to $9,000 installed

Pricing depends on:

• Panel quality (budget vs premium)
  
  
• Inverter brand
  
  
• Labour and installation difficulty
  
  
• Roof type and orientation
  
  
• Whether batteries or optimisers are included
  
  

In many cases, the cost difference between a 6.6kW system and a 6kW solar system is minimal, making the 6.6kW system a better value for long-term savings.

Government Rebates and STC Incentives

Government incentives significantly reduce the upfront cost.

For a 6.6kW system:

• STC rebates typically reduce the cost by $2,000 to $3,000
  
  
• Additional state incentives may apply, depending on location
  
  

Eligibility is based on:

• System size
  
  
• Approved installers
  
  
• Clean Energy Council regulations
  
  
• Installation location
  
  

This makes solar more accessible and increases return on investment.

How Much Roof Space Do You Need for a 6.6kW Solar System?

A 6.6kW system with 15–18 panels usually requires:

25 to 35 m² of roof space

Other considerations:

• North-facing roofs produce the highest output
  
  
• East/west-facing roofs produce slightly less but still perform well
  
  
• Shaded roofs may require micro-inverters or optimisers
  
  

If your property has limited roof space, a higher-capacity option like a 10kW solar system using high-efficiency panels can sometimes be more practical.

Key Factors That Impact Savings

Savings depend on:

1. Electricity Prices

Higher retail rates increase savings over time.

2. Feed-in Tariffs

FITs vary from 5–12 cents per kWh depending on the provider.

3. Solar Self-Consumption

Using more power during the day (e.g., running appliances) increases savings.

4. Quality of Installation

Professional installation ensures peak performance and maximum savings.

5. Seasonal Weather

High summer generation boosts annual output.

6. System Type

A system paired with a battery can further increase self-consumption.

Should You Add a Battery for Higher Savings?

A battery can significantly increase savings by storing excess daytime solar energy for night use.

Benefits of adding a battery:

• Higher energy independence
  
  
• Reduced reliance on retailers
  
  
• Backup power during outages
  
  
• Better long-term savings
  
  

A 6.6kW solar system paired with a moderately sized battery is one of the most effective setups for households that want to reduce their energy bills by up to 80%.

Is a 6.6kW Solar System Right for Your Home?

A 6.6kW solar system is ideal if:

• Your household uses 15–25 kWh/day
  
  
• You have enough roof space
  
  
• You have daytime energy usage
  
  
• You want a 3–4 year payback period
  
  
• You want strong long-term savings
  
  
• You plan to add a battery later
  
  

If your usage is higher, consider upgrading to a 10kW solar system for more flexibility and greater future-proofing.

Conclusion

A 6.6kW solar system offers impressive savings, affordable installation costs, and reliable power generation across Australia. With government rebates still available and strong yearly savings of $1,500 to $2,400, it remains the most cost-effective solar size for families.

If you want to reduce your bills, increase your energy independence, and future-proof your home, a high-quality 6.6kW solar system is one of the smartest investments you can make.

Ready to maximise your savings with a professionally installed solar system?

Request your free quote from Esteem Energy today and discover how much a 6.6kW solar system can save you.