EG4 GridBOSS MID First Look & Review: The Ultimate Solar Hack?

Here at The Solar Lab, we’ve always been huge fans of solar equipment that reduces clutter and helps you clean up your setup. When those same components also help you save money, well, that’s just icing on the cake. It turns out, the brand-new EG4 GridBOSS MID was designed to accomplish both of those aims.

Released in late 2024 alongside the EG4 FlexBOSS 21 Inverter, this compact and innovative device was made to address a specific challenge in solar installations—streamlining code compliance while cutting costs. But does it actually deliver? Let’s take a first look at the EG4 GridBOSS MID, diving into what it does, how it works, and if it’s actually the game-changer we think it could be.

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So, What is the EG4 GridBOSS MID?

EG4 lists the GridBOSS as an MID (Micro Grid Interconnected Device), which, from what we can tell, is a fancy way of saying that it’s an all-in-one system that connects your grid input, batteries, inverters, and even your generators in one organized unit. In doing so, it eliminates the external inputs, transfer switches, and other wiring that can clutter a solar setup, saving you time during the installation process, money on components, and space where you have your system installed.

But let’s get one thing straight—unlike the FlexBOSS 21 Inverter, which can operate independently, the GridBOSS MID is not an inverter, or even a standalone unit. Instead, it works as a companion to your inverter, like an EG4 18kPV Hybrid Inverter or the new FlexBOSS 21. 

On its own, the GridBOSS isn’t functional—it’s a team playing accessory for your solar system that replaces numerous other components.

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Key Features and Specifications

Here’s a quick breakdown of what the EG4 GridBOSS MID brings to the table:

• Weight: At 55 pounds, it easily passes our Tiny Baby Lift Test. Not only is it a manageable weight for one person, it’s nice and compact. It also comes with ergonomic carrying handles, which is a nice addition given how bad the handles have been on some of EG4’s earlier products.
• Power Capacity: It has a maximum power handling of up to 200 amps, which is enough to power your entire home.
• UL Certification: Like the FlexBOSS, the GridBOSS was designed to meet all safety standards and regulations in the United States, earning it full UL Certification.
• Smart Load Ports: Four smart ports allow load shedding for non-essential devices (more on this later).
  
  • Two ports rated for 60 amps.
  • One rated for 80 amps.
  • One more rated for 125 amps.
• Hybrid Inverter Support: Three dedicated ports, each supporting up to 90 amps, allow you to connect up to three hybrid inverters, like the EG4 FlexBOSS 21. This means you can build a monstrous solar power setup around the GridBOSS.
• Connectivity: There’s a Wi-Fi dongle on the side of the unit for remote monitoring and control via an app. Since it does not have a display screen and, instead, relies on LED lights, the Wi-Fi-enabled smart app could be incredibly useful for certain users.
• Bypass Switch: On the same side panel as the Wi-Fi input, there is a manual bypass switch for emergencies. It has a familiar design to the bypass switch on EG4’s other products, so it’s really easy to locate and use.
• PV Disconnect Switch: Also located on the side for added convenience.

Overall, the GridBOSS boasts a really clean design, with its wiring and components housed behind a single front door. This door even includes snap-locks for a secure hold, as well as padlock loops for added security.

Why Consider the GridBOSS MID?

When EG4 launched their earlier 18kPV Inverter, the company quickly realized that installers and homeowners were spending between $2,000 and $2,500 just to meet code requirements. This process involved purchasing multiple switches, transfer systems, and wiring cables—all from different manufacturers. The GridBOSS MID simplifies this entire process by consolidating everything into one, wall-mountable device.

At a price of $1,749 (with our SOLARLAB50 discount code), the GridBOSS MID is significantly more affordable than piecing together these individual components. And it’s not just about saving money—it’s about simplifying the installation and maintenance process.

We’ve previously praised EG4 for having a real customer-oriented brand philosophy, and the GridBOSS seems to continue that trend. There are plenty of other brands that we suspect would not put so much effort into helping their customers save money on accessories. EG4 could have also leaned more into the fact that the GridBOSS cleans up solar setups, which would have enabled them to charge a lot more than $1,749. 

EG4 could have also made the decision to package the GridBOSS and FlexBOSS 21 together, or even combine them into a single unit. Knowing that those with fully off-grid setups wouldn’t exactly need what the GridBOSS offers, they kept the two units completely separate. Again, this shows that they prefer to allow their customers to only buy what they need, rather than forcing them to spend extra on something that offers little value for their particular setup.

Basically, we’re just impressed that the brand seems to take an active interest in helping those who have purchased their inverters save some money.

Taking a Look at the Smart Load Ports: Potential Game-Changers

One standout feature of the GridBOSS MID is the four smart load ports it comes equipped with. These allow you to plug devices and appliances in for intelligent load shedding. Here’s what that actually means and how these ports work:

Imagine you have an 18kPV Inverter with a 12,000W output. If your household appliances exceed that limit—say, your water heater, air conditioner, and all of your kitchen appliances are running at the same time—the GridBOSS MID prioritizes essential loads. In other words, whatever you have plugged into your smart load ports will be deactivated until the irregular spike in power usage drops back down to normal levels.

For example:

• You could have it set up so that your water heater will be temporarily shut off while your kitchen appliances are all running. This would make sense because the water inside your water heater will stay warm for quite a while, even if it’s not actively being heated.
• Once the higher-than-normal power demand from your kitchen appliances drops, the GridBOSS automatically restores power to the water heater to make sure you have enough hot water.

This intelligent load management prevents overloads and optimizes energy use, making it a forward-thinking feature for more sophisticated solar setups. Whether you’re grid-tied or off-grid, this type of hands-off power management can be a really helpful feature.

Flexibility and Scalability

With three hybrid inverter ports, the GridBOSS MID supports massive solar systems without requiring multiple units. For example, you can connect three FlexBOSS 21 Inverters to a single GridBOSS MID, creating a centralized, streamlined setup. This not only reduces installation complexity but also minimizes costs, as you don’t need separate transfer switches or bypass systems for each inverter. 

Having such enormous scalability is also really practical for those planning to expand their setup in the future. Even if you just have a single inverter now, you have the option to purchase and install more in the future, without having to pick up an additional GridBOSS MID.

Our Final Verdict: Is the EG4 GridBOSS MID Worth It?

Even just from this first look at the unit, we think it’s pretty obvious that the EG4 GridBOSS MID is an incredibly well-thought-out device that solves real-world problems for solar installers and homeowners alike. It simplifies installations, reduces costs, and offers advanced features like smart load management—all while maintaining a sleek exterior and well-organized internal design.

At under $2,000, it’s $700 cheaper than the average cost of a manual transfer and bypass switch setup for something like an 18kPV Inverter, and it includes features that go above and beyond what you’d get with that more complicated, multi-component arrangement. 

Although we’d like to test out the GridBOSS MID more thoroughly in the future, it seems that EG4 is continuing to set the bar high for innovative, cost-effective solar solutions. Whether you’re just getting started with solar or already have a solar power system you’d like to clean up, we believe the GridBOSS MID is definitely worth considering.

🛒 Shop the EG4 GridBOSS MID & FlexBOSS 21: 

GridBOSS MID: https://signaturesolar.com

Use Code: THESOLARLAB50 for $50 Off

FlexBOSS 21: https://signaturesolar.com

Use Code: THESOLARLAB50 for $50 Off