6kW & 6.6kW Solar System: Cost and How Much Electricity Can It Generate?

As the price of solar panels drops over time, 6kW and 6.6kW solar systems are slowly coming into view. In this comprehensive guide, we will take a deep dive into all aspects of 6kW and 6.6kW solar systems, addressing key issues such as energy production, cost, battery requirements, number of panels, and upgrade potential.

How Much Energy Does a 6.6 kW Solar System Produce?

The calculation of daily energy output is straightforward: multiply the system's peak capacity (6.6 kW) by the number of effective sunlight hours per day. In regions with an average of 4-5 effective sunlight hours, the daily output can be substantial. For example, 6.6 kW multiplied by 4.5 sunlight hours yields 29.7 kWh per day, which falls within the average range mentioned earlier.

Is 6 kW Enough to Run a House?

On average, the typical U.S. home consumes about 877 kWh per month, which equates to about 29 kWh per day. Considering that a 6.6 kW solar system can generate 26-33 kWh per day, in most cases a 6 kW solar system will be more than enough to meet the energy needs of an average home, especially if you live in a sunny area and have energy-efficient appliances. If your electricity usage is higher than the national average, say 12,000 kWh per year, a 6 kW system will likely meet about 80% to 90% of your needs, meaning you'll still rely on grid power or a battery storage system to meet the rest.

What Is the Cost of a 6 kW Solar System?

On average, the cost of installing a 6 kW solar system in the United States can range from $12,000 to $18,000 before any incentives or rebates. This estimate includes both the cost of the panels and installation fees. Here's how it breaks down:

• Cost per Watt: The average cost for solar installation is between $2.00 and $3.00 per watt for residential solar systems.
  • For a 6 kW system (6,000 watts), the cost would be:
    • At $2.00 per watt: 6,000 x $2.00 = $12,000
    • At $3.00 per watt: 6,000 x $3.00 = $18,000

Factors Affecting the Cost

• Location: The cost of solar installation can vary based on local labor rates, permitting fees, and the solar energy market in your state. States like California, Hawaii, and New York tend to have higher installation costs due to higher demand and labor costs. In contrast, states with less demand might offer lower prices.

• Equipment Quality: Higher-efficiency panels (like those from SunPower, LG, or REC) can cost more than standard panels from other manufacturers. If you choose premium inverters (like microinverters) or add energy storage (batteries), this will increase the cost as well.

• Roof Type and Installation Complexity: If your roof requires special mounting systems, or if the installation is more complex (e.g., a metal roof or difficult-to-reach location), the costs will be higher.

• Permits and Inspections: Local regulations may require permits, inspections, and grid connection fees, all of which can add to the cost of installation.

Incentives and Tax Credits

• Federal Solar Tax Credit (ITC): As of 2024, the federal solar investment tax credit (ITC) allows you to deduct 30% of the installation cost from your federal taxes. This can significantly reduce the cost of your system. For example:

  • If your system costs $15,000, you could receive a $4,500 tax credit, bringing the cost down to $10,500.

• State Incentives: Many states and local governments also offer rebates, tax credits, or other incentives to reduce the upfront cost. Check with your local energy authority for available programs in your area.

• Net Metering: In some states, you can participate in net metering, which allows you to sell excess electricity back to the grid, potentially lowering your overall electricity costs and increasing the financial benefits of your solar system.

Ongoing Costs

• Maintenance: Solar systems are relatively low-maintenance, but it’s important to factor in occasional cleaning and inspections. These costs are typically minimal but could range from $100 to $300 per year for professional cleaning and maintenance.

• Warranty: Most solar panels come with a 25-year warranty, and inverters usually have a 10- to 12-year warranty. If the inverter needs replacing, this can cost anywhere from $1,000 to $3,000.

Financing Options

If paying the full amount upfront is not feasible, you can explore financing options such as:

• Solar Loans: Many lenders offer loans specifically for solar installations, with interest rates varying depending on your credit.
• Leasing: In some areas, solar leasing programs allow you to install solar panels with little to no upfront cost, but you pay a monthly fee for the use of the system.
• Power Purchase Agreements (PPA): With a PPA, you agree to buy the electricity produced by the solar system at a fixed rate for a specified period, typically 20 years.

Example Cost Breakdown:

Let’s assume a 6 kW system with a total installation cost of $15,000:

• Federal Tax Credit (30%): $15,000 × 30% = $4,500.
• Final cost after tax credit: $15,000 - $4,500 = $10,500.

What Size Battery Do You Need for a 6 kW Solar System?

Determining the appropriate battery size for a 6 kW solar system involves understanding your energy storage needs. A typical household with a 6 kW solar system produce around 30 kWh per day. To store a full day's worth of energy production, you would need a battery system with a capacity of approximately 30 kWh.

However, not all the energy produced will need to be stored, as some will be used immediately during daylight hours. If you aim to store enough energy to cover nighttime use or power your home during cloudy days, you might consider a smaller battery size, such as 10-15 kWh, depending on your usage patterns and needs.

Example Battery Options

Here are some popular residential solar battery systems and their capacities:

• Tesla Powerwall: Each Powerwall has a capacity of 13.5 kWh. For full backup, you would need at least two Powerwalls to cover 25 to 30 kWh per day.
• LG Chem RESU: The LG Chem RESU 10H has a capacity of 9.8 kWh, and the RESU 16H offers 16 kWh. For whole-home backup, you might need two RESU 10H units or one RESU 16H, depending on your energy needs.
• Enphase IQ Battery: Each Enphase IQ battery has a capacity of about 3.5 kWh. For full home backup, you would need several units, depending on your needs.

Total Battery Storage Costs

• For a 10 kWh to 15 kWh battery (sufficient for partial to full home backup for most homes), the typical cost would range between $6,000 and $20,000 depending on the battery type and system features.
• For example:
  • Tesla Powerwall: 1 unit ($10,500–$12,000)
  • LG Chem RESU 10H: 1 unit ($7,000–$8,500)
  • Enphase IQ Battery: 3 units ($9,000–$12,000)

How Many Panels Are Needed for a 6 kW Solar System?

Summary

• Number of Panels:

  • 20 panels of 300W each for a 6 kW system
  • 15 panels of 400W each for a 6 kW system

• Space Required:

  • 20 x 300W panels: 352 square feet (about 32.7 m²)
  • 15 x 400W panels: 324 square feet (about 30.1 m²)

The average solar panel produces around 300 to 400 watts of power, depending on the panel's efficiency and quality. Let’s break it down for both 300W and 400W panels:

• Each panel produces 300 watts (0.3 kW).
• To generate 6 kW of power, you would need: 6 kW÷0.3 kW per panel=20 panels
• So, with 300W panels, you would need approximately 20 panels to make up a 6 kW solar system.

• Each panel produces 400 watts (0.4 kW).
• To generate 6 kW of power, you would need: 6 kW÷0.4 kW per panel=15 panels
• So, with 400W panels, you would need about 15 panels to make up a 6 kW solar system.

Space Required for a 6 kW Solar System

The amount of space a solar system requires depends on the size of the panels. On average, a 300W solar panel has dimensions of about 65 inches x 39 inches (or 1.65 meters x 1 meter). 400W panels are slightly larger.

Space for 300W Panels:

• Each 300W panel covers about 17.6 square feet (1.64 m²).
• For 20 panels, the total area required would be: 20 panels×17.6 sq ft per panel=352 sq ft(or approximately 32.7 m²)
• So, for 20 panels, you would need approximately 352 square feet (or 32.7 m²) of roof space.

Space for 400W Panels:

• Each 400W panel typically covers about 21.6 square feet (2 m²).
• For 15 panels, the total area required would be: 15 panels×21.6 sq ft per panel=324 sq ft(or approximately 30.1 m²)
• So, for 15 panels, you would need approximately 324 square feet (or 30.1 m²) of roof space.

Additional Considerations:

• Roof Shape and Orientation: The layout of the roof can affect how efficiently the panels can be arranged.
• Tilt and Spacing: Panels need to be installed at an optimal tilt to maximize solar energy capture, which may require additional space between rows of panels for proper spacing.
• Shading: If there are trees or other obstructions that cause shading, more panels or a different arrangement may be needed.

Can You Upgrade a 6 kW Solar System?

Yes, it is possible to upgrade a 6 kW solar system. Many homeowners choose to upgrade their solar systems as their energy needs grow, or when they want to take advantage of newer, more efficient technology.

Summary: Steps to Upgrade a 6 kW Solar System

1. Add More Panels: Add 5 to 10 panels (depending on panel wattage) to increase system capacity.
2. Upgrade to Higher-Wattage Panels: Switch to higher-wattage panels (e.g., 400W panels) to generate more energy without taking up more space.
3. Upgrade the Inverter: Ensure your inverter can handle the additional power generated by the upgraded system.
4. Increase Battery Storage: Add or upgrade solar batteries to store more energy.
5. Costs: Expect to pay for new panels, inverters, and installation—typically ranging from $2,000 to $10,000 depending on the scale of the upgrade.

1. Increasing the System Size

If your energy consumption has increased, or if you want to store more energy or produce more electricity, you can add more panels or expand the battery storage.

Adding More Solar Panels

• Additional Panels: You can add more solar panels to your existing system to increase its capacity. For example, if you currently have a 6 kW system with 20 x 300W panels, you can add more panels to increase the total system size (e.g., adding 5 more panels for an additional 1.5 kW).
  • Upgrade to 7.5 kW: 25 x 300W panels.
  • Upgrade to 8 kW: 20 x 400W panels (or 20 x 300W panels plus 5 more).

Upgrading to Higher-Wattage Panels

• If you're limited on space but want to increase the system size without adding more panels, you can replace your existing panels with higher-wattage panels (e.g., switching from 300W panels to 400W panels). This allows you to generate more power with fewer panels.
  • For example, upgrading from 20 x 300W panels to 15 x 400W panels can increase your system capacity without taking up extra space.

2. Upgrading the Inverter

• Inverter Capacity: Your inverter needs to be able to handle the additional power generated by the system after an upgrade. If you add more panels or switch to higher-wattage panels, you may need to upgrade your inverter to one that can handle the increased output.
  • String Inverter: If you're using a string inverter, you may need a larger inverter model to accommodate the increased number of panels.
  • Microinverters: If you're using microinverters (one inverter per panel), the system may be more flexible, but you'll still need to ensure the new microinverters can handle the increased panel output.

3. Upgrading Battery Storage

• If you want to store more energy, or if your current battery storage is insufficient for your needs, you can add additional solar batteries or upgrade to a larger battery system.
  • Adding More Batteries: Many battery systems are modular, allowing you to add extra units to increase storage capacity. For example, if you currently have one Tesla Powerwall (13.5 kWh), you can add another to increase your storage capacity.
  • Upgrading to a Larger Battery: If you're planning to upgrade to a larger solar system, consider a battery that matches the increased capacity to store more of the generated energy.

4. Potential Costs of Upgrading

Upgrading your system comes with additional costs, but it can provide long-term savings by reducing your reliance on grid power. Here are some potential costs involved:

• Adding More Panels: The cost of additional panels typically ranges from $200 to $400 per panel, depending on the type and quality of the panel. So, adding 5 extra panels could cost between $1,000 and $2,000.
• Upgrading the Inverter: Upgrading to a larger or more powerful inverter can cost between $1,500 and $3,500, depending on the brand and specifications.
• Battery Storage: Adding more batteries or upgrading to a larger battery system can cost anywhere from $5,000 to $15,000, depending on the battery type (e.g., Tesla Powerwall, LG Chem RESU, etc.).

Conclusion

A 6.6 kW solar system offers a robust solution for many homeowners looking to transition to renewable energy.For those with higher energy demands or looking to future-proof their energy solutions, considering a larger system might be advantageous.

Recommendation: SEL 10 kW Solar System

For homeowners with larger energy needs, SEL’s 10 kW solar system is a powerful and efficient choice. This system is designed to generate approximately 40-50 kWh of electricity per day, which is ideal for larger homes or those with higher energy consumption patterns. If you need a larger system, we can provide you with solar energy solutions.