Microinverters: What you need to know

Inverters are an essential component of any solar panel system. They're responsible for converting direct current energy (DC) generated by your solar panels into usable alternating current (AC) electricity for your home's appliances. There are a few options when choosing an inverter solution for your solar panel system. In this article, we'll review one of the more popular types of inverter technologies: microinverters.

Microinverters are installed at the individual solar panel site, differentiating them from centralized string inverters (where there's typically one inverter for the whole solar system). Most solar panel systems with microinverters include one microinverter on every panel.

Because each microinverter operates at the panel site independently of the other inverters in the system, microinverters are classified as module-level power electronics (MLPE). MLPEs are the best option for complicated installations or those with marginal shading. With traditional string inverter technology, panels only can produce electricity at the level of the lowest-performing panel on the same string. This isn't a problem with microinverters – because panels have their own inverter, solar panels will continue performing efficiently even if one panel isn't producing as much electricity as the others.

The size of each microinverter depends on the size of the panel and the amount of electricity it's capable of producing (as determined by your geography, the tilt, the direction it's facing, and more). If your solar panel produces more electricity than its microinverter can convert at a given moment, "clipping" occurs, resulting in power losses.

Microinverters are useful in many solar installations but also have their drawbacks. Here are some of the important pros and cons of using microinverters to keep in mind:

Top pros and cons of microinverters

Pros of microinverters

Microinverters are an excellent investment for most solar shoppers – especially if you have a complex roof or one with partial shading. Because microinverters operate at the panel level, they don't require power optimizers for rapid shutdown compliance and optimization. Additionally, if something's wrong with one microinverter, this won't shut down your whole system, just the panel attached to that single inverter. If one of your panels is underperforming, you can identify and have your installer diagnose and fix the issue quicker than if you just had one central inverter.

It's also easier to add more solar panels to your system in the future if you have microinverters because you won't have to worry about the power output of a central inverter matching up with your new system size. Unlike string inverters, most microinverters are warranted the same amount of time as the panels they're attached to – 25 years – so you can expect them to last longer as well.

Cons of microinverters

While you'll likely have better overall system performance with microinverters, this comes at a cost. Generally, microinverters are more expensive than string inverters, so you have to weigh if the long-term performance benefit outweighs the upfront cost. String inverters typically sit on the side of your house. At the same time, microinverters are located on your roof, meaning that if one needs to be fixed, the maintenance will be more difficult (and more costly if labor isn't covered under your warranty).

As previously mentioned, the other thing to be aware of with microinverters is clipping: often, the power output rating of your microinverter is lower than that of the panel itself. So, when your solar panel's output exceeds the microinverter's production, you get clipping and don't get the full power output of your solar panel.

There are many reasons to consider installing microinverters. For one, they allow for individual panel performance monitoring. With microinverters, you can compare how each panel is performing independently rather than solely evaluating the system's performance alone. This can mean quicker equipment servicing, as it's easier to identify if a particular panel or microinverter is failing.

Microinverters are also a good solution for more complicated installations with panels facing different directions or tilting at varying angles. If you have some panels facing east and others facing south, using microinverters on each panel will allow them to perform to their maximum ability when sunlight hits them, as they will not be impacted by the production issues other panels in the system might experience.

Microinverters are typically more expensive than other inverter options. The additional upfront cost for the added monitoring and production benefits can be well worth it. If you have an easy installation on a single roof plane facing south with no shade, a lower-cost string inverter system can be an effective solution.

The three most common inverter options are microinverters, string inverters, and power optimizers. Here's how microinverters compare to the other two popular inverter types:

String inverters vs. microinverters

The most significant difference between string and microinverters is that when using a string inverter to wire your panels, depending on the size of your solar system, you only need to use one or two string inverters (usually referred to as "strings"). This makes troubleshooting more manageable if your system fails, as all 6-12 panels of the inverter supports are wired to just one destination. Given the minimal wiring requirements, string inverters are also cheaper to install and maintain than microinverters. That being said, the simplified wiring scheme can also make it more expensive to expand your solar system in the future. It also means that underperforming solar panels will affect the whole circuit rather than just its own output.

Power optimizers vs. microinverters

Unlike micro and string inverters, power optimizers don't immediately convert direct currents to alternate currents. Instead, they "condition" it and send it to a centralized inverter. These module-level power electronics, or MLPEs, are very similar to microinverters because they can monitor individual solar panel performance and allow for flexibility in building a solar system on a marginally shaded roof.

Dive into our comparison of microinverters and power optimizers to learn more.

When comparing your microinverter options, there are a few main factors to keep in mind:

Efficiency

Just like solar panels, microinverters have varying efficiencies. An inverter's efficiency measures how much energy is lost in heat during the conversion from DC to AC electricity. Higher efficiency microinverters lead to higher overall system efficiencies and more solar electricity production.

Size

Microinverters come in varying sizes, each designed to handle different voltages of electricity. Larger microinverters will often be more expensive; however, you don't want to install a microinverter that's too small for the associated panel's energy output, as that will result in too much clipping. Manufacturers of microinverters often list guidelines for the maximum DC wattage a solar panel should have when connected to their products.

Warranty

Most microinverter options available today come with a 25-year warranty, protecting you against potential manufacturing defects or undue degradation. However, even two different microinverter manufacturers that offer the same warranty term may provide different levels of coverage as part of the warranty. It's essential to read and compare warranty agreements when choosing solar equipment.

Price

Although they are not typically the most expensive component of a solar panel installation, it's still important to weigh the price you'll pay for microinverters. Higher efficiency microinverters with longer warranties often come with higher price tags but can be worth it depending on your solar panel system setup and your preferences.

Rapid shutdown requirements

When a rapid shutdown occurs, microinverters can shut down automatically in compliance. Each module has software to shut down in sync with these rapid shutdowns, so no extra hardware is needed.

Many manufacturers offer microinverter products; here are a few of the more well-known names:

Enphase

Enphase, headquartered in California, is the market leader in microinverter technologies. Their IQ series is a popular option for residential solar panel installations. In addition to manufacturing standalone microinverters, the company partners with multiple solar panel manufacturers to offer AC modules. They also manufacture energy storage and monitoring systems to pair with their microinverter products.

SunPower

SunPower, a leader in high-efficiency solar panel modules, purchased the microinverter company SolarBridge in 2014. However, in 2018 the company sold its microinverter business to Enphase. SunPower's AC modules, used in their Equinox systems, now employ microinverter technology built and designed by Enphase.

APSystems

APSystems was founded in California in 2010. Unlike many microinverter solutions, their microinverters are designed to connect to more than one panel. One APSystems microinverter can connect with up to four panels.

Solar panel systems last more than 25 years, so making a confident decision when choosing your equipment is important. On the EnergySage Marketplace, you can receive up to seven solar quotes to compare online. Given your unique situation, local installers will provide custom quotes and propose an inverter solution. These quotes will include information about your inverter options, including but not limited to warranty, type of inverter, manufacturer, and more.