Microinverters vs. Regular (String) Inverters: What’s the Difference?

Knowing which inverter type to go with as you install your solar panels is essential. There are two main inverter types: microinverters and string inverters. As each have their own advantages and disadvantages, knowing the difference between the two can aid you in making the right decision on your quest to go solar.

Beginning with the obvious question, why do you even need an inverter? Solar panels generate what is known as DC (direct current). Your house and everything in it runs on AC (alternating current.) Inverters turn DC into AC, so you can use the power generated by your panels.

Micro-inverters

Microinverters are becoming increasingly popular in the market and for an obvious reason. Microinverters allow for solar panels to perform individually, meaning if one isn’t generating sufficient energy, the rest still can. This is because a microinverter functions in a parallel circuit, which allows for each panel to perform individually, while making a group contribution towards the overall power generated.

Regular (String) Inverters:

As opposed to microinverters, string inverters function in a series circuit. This implies that solar panels will work together in a series which is known as a string. The string inverter is connected to every string of panels attached to your house or building. These are typically the least popular inverters today, simply because of the risk of losing power from one bad panel.

String Inverters w/ Power Optimizers:

In this configuration, each panel contains an optimizer that ensures optimal panel level production. Then these panels are connected to a compatible String Inverter. In this configuration, even if one panel is shaded, the string performance doesn’t degrade. This is often regarded as the best option for a residential house, as the price is much less than a microinverter, and more efficient than a string inverter. A string inverter and power optimizer setup will run about $0.30/Wp – a cheap price considering each panel essentially works on its own in the string.

When to Go with Micro-inverters

Making the choice to go with a micro-inverter vs. a string inverter can be difficult, as each have their advantages and drawbacks. For residential uses, microinverters are gaining popularity. The main advantage of a microinverter is that each panel works on its own.

Why is this important? Assume that a single solar panel is covered by a shadow and isn’t generating much power. With a microinverter this is no issue, since the other panels will operate separately and continue to generate maximum energy.

The biggest problem with microinverters are the price. The average price for a microinverter goes for around $0.44/Wp (watt-peak), which is significantly higher than a string inverter.

Microinverters are also safer as they eliminate the need for high voltage Direct Current (DC) wiring. This means that the solar panels using microinverters are less likely to start a fire as compared to those who are using string inverters.

Another great advantage of a microinverter is the smaller size. They are normally a lot easier to set up, and can be done so safely and easily by a homeowner while string inverters typically can’t.

When to Go with String Inverters

String inverters have been the go-to inverter for the past 40-or-so years. Unlike a microinverter, string-inverters work in a series. As previously mentioned, between six and ten panels work together in this string. The entire series can only work as efficiently as the least efficient panel (if one panel doesn’t work, none of them work.) So, how could this be beneficial?

The normal issue people have with string-inverters are that shadows cover one of them, meaning the series functions as if they are all covered by panels. Suppose you are in an area with nothing to block any of the panels though. In a case like this, going with something as simplistic as a string inverter may be a better option.

Even more enticing is the price of a string inverter. While the price of a microinverter is $0.44/Wp, a string inverter will only run you about $0.18/Wp.

A major downside to a string inverter is the failure aspect. If a panel is not working efficiently for an unknown reason, it can be difficult to find the problem since all 6-10 panels are working together as a whole.

When to Go with String Inverters with Power Optimizers

String inverters with Power Optimizers are greatly considered one of the best options for a residential setup. So long as you have a compatible string inverter, the setup is the same as any other solar panel. The cheap price of $0.30/Wp is appealing for the average consumer as well, coming it at over half the cost of a microinverter.

Like a microinverter, each panel basically works by itself even though it is still in a string. You’re getting a more efficient energy transition than a string inverter, paying only a few cents extra per Wp. If you live in a residential area, these may be a great suit for your solar setup.

What’s the Best Option for You?

String inverters have been the traditional option for the past 40 years, but times are changing. That is not to say that you should go with a microinverter simply because it is up-and-coming, but they are typically a lot more efficient in a residential area. Microinverters essentially negate the risk of the entire system failing because of a simple shadow, at the cost of a higher watt-peak.

Perhaps a great middle ground for you is the string inverter + optimizer option. They essentially strike a perfect balance between performance and price, as the price difference between a string inverter and microinverter is quite hefty. Given the downsides, many residential systems don’t rely solely on string inverters.

Each situation is unique and should be treated as such, but consider a string inverter + power optimizer if you are simply looking for a residential solar panel setup. PowerScout can help you in making the right solar decision for your situation. Contact us today to see the best options for your solar setup.