String Inverters: Everything you need to know

Key points

  • String inverters convert DC electricity to AC electricity at a central unit.
  • They work best in unshaded areas on a southern facing roof with a uniform pitch. 
  • If even one panel is in a shaded area, string inverter setups will have significantly reduced power production across the entire system. 
  • String inverters are significantly more affordable, but they lack panel-level monitoring capability. 
  • Typically, string inverters have a lifespan of 8 to 12 years. 

What is a string inverter?

String inverters are the most cost-effective inverter option available in the U.S. today. 

They come in the form of a centralized unit installed in close proximity to your main service panel and electricity meter. 

In most setups, there will only be one string inverter, along with 6 to 12 individual panels grouped into a series string. 

This is completely dependent on the size of the solar power system, but most larger setups will use alternative types of inverters. 

Why would I want to use a string inverter? 

Numbers assume a 1500 square foot house in California with 15 to 18 panels, no labor, permits or additional costs included. Inverters typically cost around 6% to 10% of the total solar installation cost. Assuming installation price of 15,000, with 11,280 kWh in yearly usage. 

String inverters are typically seen as a short-term, cost-effective solution due to their lower cost and equipment requirements when compared to microinverters. 

One string inverter can handle the energy of 5 to 10 panels, meaning you can save on your solar system cost because you are buying one string inverter instead of 5 to 10 microinverters. 

It is important to note that a string inverter can only perform as well as its lowest-producing panel. 

If one panel is blocked from debris or shade, your entire system will reduce its solar output. 

String inverters work best on standard, southern facing roofs that are unshaded and in an area that minimizes the risk of debris falling onto the panel. 

How does a string inverter work?

The solar panels on your roof are arranged into groups connected by strings. 

You are able to connect multiple strings of panels to one centralized unit, the inverter. 

It converts the DC electricity that your panels produce into usable, AC electricity that can be used to power your home. 

String inverters have been on the market for decades, and they have a commanding market share for both commercial and residential projects. 

They are a reliable technology, but they may not always be the best option for your home. 

Modern solar inverter and panel technology allow your system to produce power even if a panel is shaded. 

Without any sort of electrical monitoring at the panel level, string inverters will only optimize power output at the string, or system level, not with each individual panel. 

This means that if you have a property with a non-standard roof, or one with lots of periodic shading, then a string inverter setup may not be right for you. 

Despite this, many homeowners opt for string inverters because of their low cost and simple installation. 

Pros and cons of a string inverter


  • Cost: The biggest advantage of string inverters is their lower cost. Installing one single-string inverter in your solar system is far cheaper than installing micro-inverters. You’ll save money on labor and equipment upfront, which is hugely attractive for most homeowners. 
  • Easy to troubleshoot: Solar panels are typically one of the most reliable components in a solar system. Because you only need a single string inverter to convert DC electricity from your array to AC power, the most likely point of failure is the string inverter itself. This makes troubleshooting simple when things go wrong. 
  • Lower probability of wiring issue: String inverters have the simplest installation process out of all inverter types. This means that there is a lower likelihood of a wiring issue in the initial setup compared to other types of inverters.  


  • Efficiency in partial shade: One of the biggest drawbacks of string inverters is that if one solar panel’s output is affected, the entire series will go through the same power drawback. If your property gets shade for a significant part of the day, then this can have a major impact on power output. 
  • More difficult system expansion: If you buy a new electric car down the road, you may want to increase the size of your solar array at some point. Once you exceed the upper threshold of 10-12 panels, you’ll need to route any new panels to a separate string inverter, which comes with additional complexity and cost. 
  • System monitoring: If you want panel-level monitoring, it simply isn’t possible with a standard string inverter system. You’ll be able to see aggregate solar production, you want to be able to see any impacts from issues like cracks, defects, debris, or shading on individual panels. 
  • Shorter lifespan: The vast majority of string inverters are warrantied to last between 8 and 12 years. On the other hand, most microinverters have a 25-year warranty, making string inverters one of the shortest-lasting inverter types. 

String inverter vs microinverter

Micro-inverters do offer a clear advantage when it comes to power production, and give you access to individual level panel monitoring that can help you troubleshoot system issues with ease. 

In the event of an issue, they have the ability to rapidly shut down, protecting your system from catastrophic energy related damage. 

With an average of 25 years for their lifespan, micro-inverters are the clear winner for their time as well. 

The inverter is the most complex, failure-prone component in a solar system. Microinverters put dozens of inverters in low-access locations on your roof. 

This presents a pretty significant issue if there is a system issue, as maintenance and repairs can be complex and time consuming. 

Ultimately if you have the budget for them, microinverters are a better choice over string inverters for most Americans.  

It is always worthwhile to get a solar consultation before making such a significant investment. 

String inverter rapid shutdown

Rapid shutdown is an electrical safety requirement set out by the NEC (National Electrical Code) that mandates the ability for a homeowner to be able to swiftly de-energize their solar panel system. 

Why was it mandated? The main reason was to keep first responders safe in case of a fire in your home. 

If firefighters need access to your roof, they risk electrocution if solar panels are not shut down. High DC voltage levels can be extremely harmful to human health. 

Simply turning off a solar inverter system is not enough to actually de-energize your setup. 

Now, with that in mind, there is an important element to note here: many string inverters do not have rapid shutdown capabilities. 

String inverters are particularly risky because multiple solar cells are connected in a series, leading to extremely high voltages in excess of 1,500 V. 

While newer string inverters typically come with the ability to go through a rapid shutdown, this is a critical element that you want to ask about before purchasing a string inverter system. 

Should I purchase power optimizers for my setup? 

Power optimizers help to solve many of the problems that traditional string inverters bring, but at a pretty high cost. 

They are affixed to the back of each panel to condition the voltage before sending it to a central inverter. 

This allows you to get some of the benefits of a microinverter, like better performance in partially shaded conditions, and individual panel-level monitoring. 

In many cases, customers who add power optimizers to their solar array setup can expect to see an energy production improvement of about 25%. 

Is a string inverter worth it?

Right for you if…

May not be right for you if…

  • You want a cost-effective setup
  • Your roof is standard and faces south 
  • Your property isn’t highly shaded 
  • You don’t have many trees or any objects that could cause debris to land on your panels 
  • You don’t want panel-level monitoring
  • You have the budget for a microinverter setup
  • You have a non-standard roof with some shading 
  • You want panel-level monitoring 

It’s no secret that the most complex electronic device in a solar panel system is the inverter. 

Our experts at Spark Change have almost a decade of experience in solar technology, and we can confidently say that the most issue-prone component is the inverter. 

Despite the claim that most micro inverter setups allow panel-level monitoring, in many cases, they ask you to pay a higher subscription fee in order to get access to that feature. 

In many cases, the installer is the only one who will have access to the advanced monitoring. 

It is very difficult to diagnose an issue with a single inverter when you only have access to system-level monitoring. 

Ultimately, if you have a standard, south-facing roof in an unshaded, debris-free area, a string inverter is a great option for you and your family. 

If you want to learn more about inverter technology to find the right system for you and your home, connect with our team at Spark Change for an assessment.