Solar Inverters: Pros And Cons Of String Inverters Vs. ...

Solar inverters have one core function: convert the direct current (DC) solar panels generate into an alternating current (AC) used in your home. There are two main types of home solar inverters:

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• Microinverters attach to the back of each panel and are best for complex solar installations.

• String inverters connect strings of panels in one central location and are best for simple installations.

Microinverters have become the most popular inverter option because they are compliant with National Electrical Code and safety standards. String inverters need to be paired with DC optimizers or rapid shutdown devices to be up to code. 

There are pros and cons to each type of solar inverter, and the right one for you ultimately depends on your system design. 

How much do solar panels and inverters cost?

Solar inverter types

There are two main types of solar inverters for home solar installations:

• String inverters

• Microinverters

Each one converts energy from your solar panels into electricity your homes can use, but how they get it done is a bit different.

String inverters

A string inverter is installed on your home, typically close to your main service panel or electric meter. The electricity generated by a string of solar panels is sent to the inverter, where it&#;s converted to AC current and sent to your home appliances. 

Because of how the solar panels are wired together, if there is an issue with one panel in the string, the energy production of all the panels strung together will be impacted. For example, if one panel in a string is shaded and produces less energy, all of the other panels in the string will match that shaded panel. 

There is typically only one single string inverter installed for a residential solar installation, and they are very popular for solar systems installed on simple, unshaded roofs.

String inverters are often paired with DC power optimizers to meet electrical code standards. Power optimizers are attached to the back of each panel and track the panel&#;s peak output. The optimizers can then regulate voltage before the power gets sent to the string inverter, maximize the amount of energy the system produces, and reduce the impacts of shading.

Microinverters

Microinverters perform the same basic function as string inverters, except they are installed underneath each solar panel on your roof. Some microinverter models allow you to attach two or four panels to each unit.

With a microinverter, the DC to AC conversion is completed right at the back of the panel. 

While standard string inverters will cap the electricity production of each panel by the lowest-producing panel in a string, microinverters don&#;t have this problem since they function in a parallel circuit.

A microinverter takes full advantage of the production of each individual panel. Each solar panel and microinverter combination can &#;do their best&#; and contribute as much power as they can. Microinverters work best for complex solar installations on multiple roof faces.

Hybrid inverters. Solar systems paired with battery storage may use a hybrid inverter that connects the panels, the battery, the grid, and your home together in one unit. Hybrid inverters are efficient and allow for a streamlined design. However, they are becoming less common as more batteries are being sold with built-in inverters.

Pros and cons of solar inverters

Every home solar panel system needs inverters to operate. But the right one for you depends on the system&#;s design. Let&#;s take a closer look at some of the advantages and disadvantages of each inverter type.

String inverter pros and cons

Pros

• Easy to troubleshoot

• Low cost

• Simple system design

Cons

• Efficiency in shade or single-panel issues

• Difficult system expansion

• 10-year lifespan

• Additional equipment needed for rapid-shutdown requirements

• Inverter issue impacts entire system

One of the biggest benefits of string inverters is their simplicity. Often, if there is an issue with a solar system, it has to do with the inverter. With string inverters, there&#;s only one, so troubleshooting and repairing the issue is easy, and no one has to get on your roof to repair it.

String inverters are also cheaper than other inverter options, but keep in mind that you do often have to pair the system with optimizers or rapid shutdown devices, which will increase the cost.

The downside to string inverters is that issues with one panel can impact the energy production of the other panels it&#;s wired to, lowering how much electricity your home has to use and eating into your solar savings if not addressed right away. DC optimizers do help with this issue, but having to get additional equipment is a bit of a hassle. Also, if there is an issue with the string inverter, your whole system will be offline until it&#;s repaired.

Because of how the panels are wired together and the voltage requirements of string inverters, they aren&#;t the best choice for complex system designs that have panels on multiple roof faces and aren&#;t great if you try to add more solar panels in the future. Plus, string inverters have a short lifespan of 10 years &#; solar panels last for at least 25. So, you&#;ll likely have to replace your string inverter at least once.

Microinverter pros and cons

Pros

• Meets rapid-shutdown requirements

• Easy system expansion

• Panel level monitoring

• Individual panel performance doesn't impact others

• 25-year lifespan

• Make it easier to add panels to an existing system

Cons

• Difficult to repair

• Expensive

• More points of failure

Microinverters have quickly become the most popular choice for residential solar installations - and for good reason! They don&#;t require additional equipment to meet electrical code requirements, can be used for intricate system designs, and don&#;t have the same shading issues as string inverters. Because microinverters output AC power from each solar panel, it makes it easier to add more solar panels to an existing system. Microinverters also have a 25-year lifespan, so you don&#;t have to worry about getting them replaced after 10 years.

But, when there is an issue with microinverters, it can be difficult to repair. First, the defective microinverter has to be properly identified on your roof. Then, an installer needs to get up there, find, and fix it. This is much more difficult than troubleshooting a string inverter on the side of your house. The upside is that if there is an issue with one microinverter, the rest of the system can keep operating and powering your house with solar energy.

Also, there is exponentially more equipment used in a microinverter system than a string inverter system. This means there are more points of potential failure and a higher price tag.

What are the top solar inverter brands?

If you&#;re getting solar quotes, it&#;s highly likely that you&#;ll see one of two brands listed for inverters - Enphase or SolarEdge.

Enphase is far and away the number one choice for microinverters. Its products are trusted by installers nationwide, and the company has a good reputation when it comes to customer service. Regarding microinverters, we would stick with Enphase because of its reputation. You don&#;t want to cut corners when it comes to your inverters. 

SolarEdge is one of the most popular choices for string inverters and DC optimizers. SolarEdge is another brand that has been around for a long time that installers feel comfortable working with. We have seen some reports of less-than-great customer service, but it&#;s not an accident that their systems are popular.

Learn more: Enphase vs. SolarEdge inverters

There are some other brands you may come across when looking at inverters, like:

• SMA 

• GoodWe

• Fronius

While not as popular, these are still trustworthy brands that can keep your solar system up and running.

Microinverters vs. string inverters: which is best for your home?

The right inverter for you ultimately depends on your home and the type of solar installation you get.

If you have a simple roof, your panels are only getting installed on one side of your home, and you don&#;t have a ton of issues with shading, we would recommend getting a string inverter and DC optimizers. The optimizers give you the benefit of maximizing your panel&#;s power production, but you still enjoy the ease of having just one inverter and the lower price point.

Microinverters are the better choice if your system design is more complex, like if you have panels on more than one roof plane. Also, if your panels receive partial shade throughout the day, you&#;ll definitely want to go with microinverters. It may be a slightly higher price in the end, but you&#;ll get more savings by maximizing each individual panel&#;s power production.

See how much solar panels will save you

Key takeaways

• Inverters convert DC electricity to AC electricity, which your home appliances use.

• String inverters are standalone boxes ideally suited to unshaded solar panel arrays on roofs with uniform pitch.

• Microinverters are affixed to the back of every solar panel and maximize the output of each solar panel independent of the production of any neighboring panel, making them smart to use on partially-shaded solar installations.

• String inverters do not have native rapid shutoff capabilities on their own, whereas microinverters do.

• String inverters, while more affordable, do not have panel-level monitoring capabilities and come with a shorter lifespan of 8 to 12 years.

If solar panels are the brawn of your solar energy system, the inverter is its brain, and they work together to ensure you get the maximum amount of electricity. Most people are familiar with solar panels because they&#;re the most visible part of a solar power system, but the solar inverter is an equally important component to consider, as it allows electricity from the sun&#;s rays to be converted into useful electricity for your household.

In this guide, we&#;ll look at what a solar inverter does, how solar inverters work, why you need solar inverters, and how much a solar inverter costs.

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How A Solar Inverter Works

Solar panels generate Direct Current (DC) electricity, but your home runs off of Alternating Current (AC) electricity, so you have a problem: Your household needs some help to use the energy from the sun. That's where a solar inverter steps in.

So what is an inverter? A solar panel inverter&#;s primary purpose is to transform the DC electricity from solar panels into usable AC electricity for your home. Because of this, you can also think of the solar inverter as a solar converter.

Since most appliances use AC power, your solar power system has to convert this DC energy to useful electricity before it can be used to power those appliances. The brain behind this conversion is your inverter, which allows your solar power system to provide energy to your electronic devices.

For a more thorough explanation of this process, check out How Does Solar Energy Work?

Are you interested in learning more about OEM solar inverters manufacturer? Contact us today to secure an expert consultation!

Also, when a solar-powered home is connected to the grid, the inverter for home energy acts as the middleman between your home and the electric grid. This is called a grid-tie inverter. A grid-tie inverter allows your home to have uninterrupted power, no matter how much energy your solar panels are generating.

In a situation where your solar power system is producing more electricity than your home is consuming, the photovoltaic inverter can feed that extra power back into the grid. Or you might be in a situation where your panels are producing some power, but not enough to run your entire home, so the inverter mixes the solar power with grid power.

At night, when solar panels aren&#;t producing electricity, your home may need 100% of its energy from the grid, or the inverter might be able to mix some grid power with some energy stored in solar batteries.

Either way, it&#;s the grid-tie inverter&#;s responsibility to make sure your home has all the power it needs in any of these scenarios, and you don&#;t notice a change as it switches between them.

DC vs AC Electricity

The best way to answer, &#;What does an inverter do?&#; is to understand the difference between DC and AC electricity.

Direct Current (DC) electricity involves the flow of electric charge only in a single direction. On the contrary, Alternating Current (AC) electricity is where the current's flow changes direction (or alternates direction).

In the US, the electric grid uses 60 hertz AC, which means the electricity switches direction 60 times per second.

When the sun&#;s rays hit your photovoltaic (PV) panels, they trigger the movement of electrons in the solar cells. This movement is in one direction, which leads to the generation of DC electricity. The circuits inside your solar panels collect this current and feed it to the solar PV inverter, which turns the DC electric current into AC electricity.

Benefits of a Solar Inverter

While your solar PV inverter allows you to get usable current from the sun&#;s rays, that's not all it&#;s capable of. A solar panel inverter can help maximize your energy production, monitor your system&#;s output, communicate with the utility grid, and detect faults that might otherwise damage your solar power system.

Maximizing Energy Production

Solar inverters track your solar array&#;s voltage to maximize the power that the solar panels operate at, so you can generate the most and cleanest electricity possible.

Grid-tied home solar inverters also output a more pure sine wave (a measure of how smoothly the direction of current changes) compared to low-cost inverters that generate a modified sine wave, which ensures the smooth and efficient functioning of your sensitive appliances.

Monitoring System Output

It's exciting to see your solar power system generate thousands of watts on a sunny day, so naturally, most homeowners want a way to monitor the performance of their investment.

Most solar panel inverters come with some way of viewing how much energy they are currently producing, and some even allow you to track your solar system&#;s performance through a mobile app or website.

If things aren&#;t working as they should, some home inverters check the performance of your solar power system automatically and alert you if it detects an issue with any component. You can also use the home inverter&#;s performance tracking to periodically check how your system's components are working yourself, and make sure it&#;s generating the correct amount of electricity.

Communicating With the Utility Grid

In case of a temporary power outage, solar inverters ensure electricity is not transmitted from your panels to the external power lines. That way, any line worker who may be checking or repairing the grid will be protected from injury.

If you have a full solar battery bank, or your household doesn't require all of the solar electricity being generated, the inverter can also feed the surplus electricity into the grid to help you generate net energy credits.

Fault Detection

Aging and degradation of your electrical wiring and solar equipment can have the potential for hazardous electrical faults, like ground faults or arcs, if not properly maintained. If such an event occurs, the solar power inverter will quickly detect the issue and shut down, thereby protecting the rest of the system, and alerting you about a service need before any additional damage occurs.

See how much you can save by going solar with Palmetto

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My electric bill is

$290

/mo

Comparing Different Types of Solar Inverters

The solar power inverters your solar company will use depends on the complexity of your roof, the extent and frequency of shade on your roof, the purpose of your solar power usage, your residential area's utility guidelines, the manufacturers they have contracted with, and other factors.

The four main types of solar power inverters are string inverters, microinverters, power optimizers, and hybrid inverters, and each has advantages and disadvantages.

String Inverter

Also called a 'central' inverter, a string inverter is suitable for more simplistic solar power system designs. An array (group) of solar panels is connected into a 'string,' and you can connect several strings to one central inverter. The electrical energy flows from the panels into the central inverter, which then converts the DC electricity into AC electricity before making it available to power your home.

A string inverter is the easiest to maintain since it's usually located in the basement, garage, or other easy-to-access location. It's also the cheapest, as you only need one inverter to accommodate several strings of panels across several roof planes. Lastly, a string inverter is usually more durable, since it&#;s a simpler setup that performs a more basic function.

The downside of a string inverter is that underperformance in one panel can affect the other panels in that string. Since a string inverter can&#;t optimize for the performance of each panel, it's not a good match for roofs that have regular shading. Additionally, a string inverter doesn't work well in complex system designs where panels aren&#;t easily matched together into strings.

A string inverter is usually the best option if you want a lower-cost solution, and your property's roof is a basic layout and receives consistent sunrays.

Microinverters

Unlike string inverters (which are central) microinverters are distributed, and a small inverter is installed next to each solar panel. Instead of power flowing from all panels to a single inverter before being converted, this system transforms DC to AC electricity right at the panel.

Microinverters are a good choice for homes where the solar array's design is complicated or the roof has consistent shading. They maximize each panel's performance at the site to mitigate the effects of shading, and you can monitor your system's output at every panel.

Another benefit of microinverters is that they can make it easier to expand your system size in the future, since each new panel comes with its own inverter. With a string inverter, the inverter is usually sized for the number of panels that will be installed initially, so it&#;s not designed to handle additional electricity generation.

The downside of microinverters is that they&#;re more expensive than string inverters. Additionally, because they are located on the roof, maintenance can be more challenging if they need to be serviced.

Microinverters are best for maximum energy output on a complicated roof, where panels face various directions, or areas that have issues with shade.

Power Optimizers

Power optimizers are a compromise between string inverters and microinverters. Like a string inverter, the energy from your panels goes to a central inverter. However, power optimizers are located next to individual panels, just like microinverters.

Power optimizers work by optimizing the electricity voltage (thereby conditioning the DC electricity) before sending power to the string inverter. By maximizing each panel's output, they can mitigate the effects of shading on any individual panel.

If your home has a complicated roof (think roofs with chimneys, gables, and other obstructions) then power optimizers can help optimize your system for those challenges as well.

The main downside to power optimizers is the increased cost over a basic string inverter, although they do typically cost less than microinverters. And like microinverters, power optimizers can make maintenance more complicated.

Power optimizers are the best option if your roof is more complicated, and you're looking for improved performance without having to invest in microinverters.

Hybrid Inverter

Hybrid inverters are the newest addition to the world of solar energy inverters. The hybrid inverter is a combination of a PV inverter and battery inverter, and you can get it in a straight string and optimized string configuation.

The main advantage of a hybrid inverter is that it can convert electricity in both directions, so it can convert DC electricity from solar panels to AC for the home, and it can also convert AC electricity from the grid to DC power to do things like charge a solar battery or an electric vehicle.

Homeowners looking at energy backup options are embracing this technology since you can install it just like a traditional inverter, and then you don't incur a lot of additional cost when it comes time to add a battery to your system.

Once you have that battery, you can pull energy from the grid to charge it up, so you can store energy when it&#;s more affordable, and then use it when rates are higher and solar power isn&#;t providing 100% of your energy demands.

With the increasing use of Electric Vehicles (EV), some hybrid inverters also come with the added benefit of being able to help charge EVs. Since you can connect an EV charger directly to the hybrid inverter, you don&#;t have to pay more money for main panel upgrades.

Again, the main downside here is cost, and hybrid inverters are also similar to string inverters, so they don&#;t adapt as well to more complicated roof designs or shading.

Hybrid inverters are a good option for people who are considering energy storage options or have plans to add an electric vehicle that they want to charge with the sun.

Solar Inverter Efficiency

During the inverter's DC to AC electricity conversion, some energy gets lost in the form of heat. Higher quality solar power inverters are more efficient, so they convert more electricity and don&#;t have high losses during this conversion process.

Conversion efficiency varies by brand, but most quality inverters are around 97% to 99% efficient, so the energy loss is relatively minor. That said, shading and other factors can have an impact on energy system efficiency, and your photovoltaic inverter plays a role in minimizing those losses.

Solar Inverter Sizing

Inverter manufacturers usually specify the input energy that their products can handle, plus their maximum power output. For instance, a string inverter whose maximum input energy is 4,000 watts can handle up to 4,000 watts of energy from solar panels.

In the real world, you'll rarely achieve your inverter's nameplate power rating (achieved at Standard Test Conditions, or STC). In fact, your typical daily activities might end up as much as 20% below the name plate power rating.

To keep costs down, solar power inverters are often selected that have a maximum input power that is lower than your solar panel&#;s maximum output. This results in some clipping at maximum power production, where the system isn&#;t designed to handle the maximum amount of power that the panels can produce, since you&#;ll rarely see that power level on most days.

Inverter Clipping

One crucial step when designing a solar power system is to make sure the photovoltaic inverter size is matched with the solar array size for optimum power conversion. You may be surprised to learn that it&#;s usually not an exact match, and just because you have 5kW of solar panels doesn&#;t mean you&#;ll pair them with a 5kW inverter.

Typically it&#;s more cost-effective to pick an inverter that is designed to handle less electricity than the maximum amount of power that the solar panels can generate. When the panels are generating extra electricity that the inverter can&#;t handle, it&#;s called clipping, since that extra electricity is lost to the system.

If you think of electricity production as a wave, where it ramps up during the day as the sun gets higher in the sky and provides more direct sunlight, inverter clipping just means the very top of the wave gets cut off.

That said, it makes sense to &#;throw away&#; this extra electricity because a solar panel array rarely produces its maximum output. It&#;s better to design the system to handle the normal amount of power that&#;s to be expected, even if it means losing a little bit of capacity on extremely productive days. If you design a system that can handle the maximum amount of power generation, most of that production capacity goes unutilized on typical days.

Local Solar Inverter Regulations

A good solar installer will know if your locality has specific rules governing the utilization of solar energy, and any rules and interconnection regulations concerning net metering. For instance, qualifying for net metering in many states requires your solar system to adhere to a stipulated maximum size or maximum amount of energy production as a percentage of your typical consumption.

The system&#;s size limit typically depends on your inverter's (not your panel&#;s) maximum energy production, since that determines the total amount of power your installation can feed back to the grid.

How Much Does A Solar Inverter Cost?

Narrowing down the price of a solar PV inverter to a single number is tricky because every system design is different. Photovoltaic inverter requirements depend on the overall system design, and the size can be scaled up or down depending on your home&#;s energy demands.

In addition, installers typically buy in bulk and have direct relationships with suppliers, so their costs may be different than what you&#;d pay to buy direct.

String inverter prices typically range between $1,000 and $2,000 or more, which includes cost factors like the system's size, the type of solar agreement, the seller, and any features specific to your locality.

Power optimizer prices typically range between $50 and $200 or more, but keep in mind that you&#;ll need to purchase one power optimizer per panel, and you also need an inverter to connect them into.

Microinverters are more expensive than string inverters, and can cost $1,000 or more above what a comparable string inverter would cost for the same size system. Keep in mind that string inverter sizing can be adjusted with a lower incremental cost, so a string inverter that&#;s twice as big isn&#;t necessarily twice as expensive. In contrast, microinverters need to be installed on every panel, so double the number of panels will likely cause your inverter cost to double as well.

How Long Does A Solar Inverter Last?

String inverters typically have an expected lifespan of 10 to 15 years, though if it&#;s mounted in a cool and well-ventilated location and maintained properly, it can last up to two decades.

Microinverters and power optimizers entered the industry more recently, so there&#;s less data around their expected lifespan. That said, most manufacturers are confident that their products can outlast the 20- to 25-year warranties that come with the products.

What Inverter Is Right for My Home?

If you're looking to invest in a solar power system for your home and trying to decide what inverter option is right for you, an easy way to get started is with our free Solar Savings Estimator.

You'll get an estimate of the money you would save with home solar, and it factors in typical installation requirements for your region, like the type of inverter that is normally recommended.

You'll also get connected with a solar expert who can review the different solar options that make sense for your home, including inverter options, and help you select the one that's right for your family&#;s needs.

See what solar can do for you:

My electric bill is

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/mo

About the Author

Cory O'Brien

Senior Director - Growth Marketing

Cory brings over 8 years of solar expertise to Palmetto, and enjoys sharing that knowledge with others looking to improve their carbon footprint. A dog lover residing in Asheville, NC with his wife, Cory graduated from UCSB. If you run into him, ask him about the company he founded to rate and review beer!

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