Choosing the Right Inverter Size for Your Solar PV Installation: What You Need to Know

When installing a solar PV system, one of the most important decisions you'll make is choosing the right inverter size. The inverter is the heart of your solar system, converting the direct current (DC) generated by your solar panels into alternating current (AC) used by your home or business. We’re here to help you understand the different inverter sizes, their benefits, and the regulatory requirements like G98 and G99 application processes.

Why Is Inverter Size Important?

The inverter size plays a crucial role in how efficiently your solar PV system operates. It must be matched to the size of your solar array to maximize energy production and ensure your system runs smoothly. If your inverter is too small, you’ll waste potential energy; if it's too large, it could lead to inefficiencies and unnecessary costs.

Understanding Different Inverter Sizes

1. Small Inverters (up to 4kW)

   
   

   • Ideal for: Small households or properties with limited roof space.

   • Energy use: less than 3500kWh annually

   • Benefits: Affordable, easy to install, and perfect for homes with low energy needs.

   • Considerations: These inverters are suitable if you have a smaller solar array (typically around 10-12 panels). They’re less likely to cause grid export issues and usually require minimal paperwork.

     
     

2. Medium Inverters (4kW to 5kW)

   
   

   • Ideal for: Medium-sized homes or small businesses.

   • Energy use: less than 5000kWh annually

   • Benefits: Can handle larger solar arrays, allowing you to generate more electricity and achieve greater energy savings.

   • Considerations: Offers more flexibility for households with higher energy usage. This size is a popular choice for most residential installations.

   
   

3. Large Inverters (5kW and above)

   
   

   • Ideal for: Large homes, commercial properties, or anyone with high energy demands.

   • Energy use: more than 5000kWh annually

   • Benefits: Suitable for larger solar arrays, maximizing energy generation and storage capabilities.

   • Considerations: These inverters may require more paperwork, such as additional grid connection approval. They also tend to be more expensive upfront but offer the best return on investment for larger systems.

Choosing the Right Inverter Size

Your ideal inverter size will depend on:

• The size of your solar array: The total capacity (in kW) of your solar panels should closely match your inverter size.

  
  

• Your energy consumption: Consider your current and future energy usage, especially if you plan to add electric vehicles or heat pumps.

  
  

• Export limits: The inverter's ability to manage the amount of energy you export to the grid.

Understanding G98 and G99 Application Processes

In the UK, solar PV installations over a certain size require approval from the local Distribution Network Operator (DNO) through the G98 and G99 processes.

G98 Application Process

• For inverters up to 3.68kW: Most domestic solar installations fall under the G98 regulations, which allow you to connect to the grid without prior permission.

  
  

• Benefits: A straightforward process with minimal paperwork.

  
  

• Considerations: This process covers smaller installations that do not significantly impact the local grid.

G99 Application Process

• For inverters over 3.68kW: Larger installations require a G99 application, and you must get approval from your DNO before connecting to the grid.

  
  

• Benefits: Allows for more extensive solar systems, making it ideal for larger homes and commercial properties.

  
  

• Considerations: The G99 application is more complex and involves a detailed assessment of how your system will interact with the grid.

Key Tips for Choosing the Right Inverter Size

• Match the inverter size to your solar array: Aim for an inverter size that matches around 80-100% of your solar array's capacity.

  
  

• Consider future expansion: If you plan to add more panels or increase your energy usage, choose an inverter with some extra capacity.

  
  

• Understand grid connection rules: Ensure your installer handles the G98 or G99 application to avoid delays.

Ready to Choose the Right Inverter?

At FEC Renewables, we guide you through every step of your solar installation, ensuring you select the best inverter size for your needs. With expert advice and quality installations, we make your transition to solar energy smooth and efficient. Click here to learn more.