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Best Solar Inverters of September 2023 - CNET

Inverters turn the electricity generated by your solar panels into something your home can use. These are our picks for the best.

We examined the specifications of several of the most common and widely available solar inverters on the market. The SolarEdge Home Wave Inverter was our top pick. It was the most efficient inverter we looked at, meaning you'll get to use more of the energy your solar panels generate. SolarEdge also scored well for strong warranties and for an app that received high marks from users. Solar Packages

Best Solar Inverters of September 2023 - CNET

Without a solar inverter, you wouldn't be able to use solar panels to power your home. But what the heck is it?

A solar inverter's job is simple: It converts direct current, or DC, electricity generated by your solar panels into alternating current, or AC, electricity that your appliances can use. But not all solar inverters are the same. Selecting the right solar inverter for your home is tricky. That's why the solar installer usually handles the task. But installers often carry more than one inverter. Here are some you might come across during your solar journey. 

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Each inverter on this list is put through a methodology process and given a score. To develop this methodology, I read and compared dozens of inverter spec sheets, and spoke with engineers and industry experts to determine what actually matters when selecting an inverter for your home. 

Only single-phase, grid-tied and hybrid inverters for homes in the US were reviewed. DC power optimizers weren't included in the reviewing and scoring of any of the string inverters mentioned in this article. However, DC power optimizers are popular additional components you can choose to install along with your string inverter. We also want to point out that we didn't do any hands-on testing with any of the inverters on this list.

Can solar panels save you money?

Interested in understanding the impact solar can have on your home? Enter some basic information below, and we’ll instantly provide a free estimate of your energy savings.

Hands-on testing of solar equipment and companies is difficult. We examine technical specifications, talk with companies and consider customer reviews to find the best product available.

SolarEdge's Home Wave Inverter is our pick for the best inverter, earning high marks in nearly every category.

It has the highest efficiency rating of any residential inverter we've seen. And it's available in a variety of sizes, with a solid warranty. The app has very high user review scores too. SolarEdge inverters do tend to be pricey though.

The SolarEdge Home Wave Inverter is a grid-tied string inverter available in six sizes from 3.8 kW to 11 kW. It has by far the highest peak efficiency rating and CEC efficiency rating of all the inverters we've looked at. It has a peak efficiency rating of 99.20% and a CEC efficiency rating of 99%.

This means you'll barely be losing any of your generated electricity. SolarEdge's app also has the highest user review scores of any other inverter apps we've seen. This SolarEdge inverter comes with a 12-year limited warranty, with an option to extend it to 20 or 25 years at an additional cost.

Hands-on testing of solar equipment and companies is difficult. We examine technical specifications, talk with companies and consider customer reviews to find the best product available.

The best way to describe Tesla's solar products is 'well-rounded'. The same holds true for Tesla's solar inverter. It has solid efficiency ratings and app user review scores. This inverter also has the longest limited inverter warranty we've seen. But it only comes in two sizes and Tesla's customer service reputation is poor too.

The Tesla Solar Inverter is grid-tied and available in two models: 3.8 kW and 7.6 kW. It has a 12.5-year warranty, which is the longest limited warranty of any string inverter that we looked at. It has a peak efficiency of 98.60% and a CEC efficiency rating of 98%. The Tesla app's user review scores are decent, but not perfect.

The Tesla app's user review scores are decent, but not perfect. However, user review scores for the Tesla app are much higher than most other inverter apps. The Tesla solar inverter also tends to be cheaper than other string inverter options.

Hands-on testing of solar equipment and companies is difficult. We examine technical specifications, talk with companies and consider customer reviews to find the best product available.

There aren't as many microinverters to choose from in comparison to string inverters. But Enphase's IQ8 Series are the best residential microinverters we found. Each one is fairly efficient and comes with a 25-year warranty. Enphase falls short in the customer support and sizing categories. Pricing is similar to other microinverters we've seen.

Enphase has six IQ8 models. They're grid-agnostic, meaning they are grid-tied and can, with the right equipment, also power your home during an outage without needing a battery. Each microinverter is warranted for 25 years.

IQ8 microinverters have a peak efficiency rating range of 97.4% to 97.6% and a CEC efficiency rating range of 97% to 97.5%. Overall user review scores for Enphase's app, Enphase Enlighten, are favorable.

Hands-on testing of solar equipment and companies is difficult. We examine technical specifications, talk with companies and consider customer reviews to find the best product available.

Growatt is the best hybrid inverter we found during our search. It's available in a variety of sizes and comes with a fair warranty and efficiency ratings. It's also cheaper than other inverters, which is surprising because hybrid inverters tend to be more expensive. But Growatt's app isn't the most user-friendly and can be a bit buggy.

Growatt's single-phase hybrid inverters are available in nine sizes from 3 kW to 11.4 kW, so you'll likely find at least one size that fits your solar panel system's wattage. A hybrid inverter is essentially a solar inverter and battery inverter combined into one unit, making it a good inverter option if you have solar storage plans in the future. Efficiency ratings are decent too, However, Growatt customers don't seem to have the best experiences using the accompanying app software. Most user complaints seem to center around buggy or failing app software and bad customer support.

Like any other type of solar equipment, not every solar inverter is right for every home. Solar is a site-specific and personalized decision process, and finding the "best" inverter for your home would be extremely difficult without an on-site consultation. We also only looked at single-phase, residential-use inverters that are included in the California Energy Commission's Solar Equipment Lists Program for this list. We did not perform any hands-on testing. 

Instead, we focused on relatively objective ways of evaluating and comparing these solar inverters to see which ones stand above the competition. Here's how we found the best solar inverters. 

The first step was determining which categories would be used to evaluate each inverter. We then gave each category a weight. The weight we gave each category reflects the importance we felt was relevant to the average consumer. After a thorough research process and speaking with some subject matter experts (who did not influence the choices we made for this list), these were the categories (and their weights) we chose to evaluate each inverter on.

We looked at 10 of the most popular inverter brands on the market and collected the data for each category to compare the numbers. Each category (for every inverter) was given a tier-style rating (from 1 to 5) to evaluate which aspects of each inverter were above average (among our list), just average or below average. 

Chilicon Power Microinverters: Chilicon Power is another microinverters option, but these are less efficient and more expensive than Enphase's IQ8 series microinverters. Chilicon Power's microinverters are also only available in two sizes and suffer from unfavorable user app scores. 

Delta Single Phase Transformerless solar inverter: Delta's solar inverter isn't a terrible option, but there are better options. The inverters that scored the highest in our list have better warranties, efficiency ratings and better overall user app scores. However, Delta does seem to have a much better customer support reputation than other manufacturers on this list. 

Fronius Primo: Fronius Primo's single-phase inverters have lower efficiency ratings and user app scores than other inverters on this list. The limited warranties on the Fronius Primo inverters are also the shortest inverter warranty periods we've seen (5 or 7 years). But it's still worth calling out their extremely wide sizing variety, with nine sizes ranging from 3.8 kW to 15 kW.

SMA Sunny Boy: The SMA Sunny Boy received an average score in nearly every category. But with other inverters receiving above average scores, average just isn't good enough. 

Sol-Ark: Sol-Ark's residential hybrid inverter is expensive, and its efficiency ratings and warranties aren't as good as other inverters on our list. The Sol-Ark app has also received poor user review scores for its software. 

Picking which type of inverter setup you want for your home's solar panel system is arguably the most important part of your inverter decision. 

"Residential solar installations can look really different depending on what the residence looks like," Rachel Kurchin, assistant research professor of materials science and engineering at Carnegie Mellon University, told CNET. "Maybe your house has a really slanted roof or maybe there are trees around that shade it for part of the day, or maybe that's not so much of an issue. Those are the kinds of things that can make a real difference in what type of inverter solution makes the most sense."

When it comes to home solar installation, homeowners have three types of solar inverter to consider: string inverters, string inverters plus DC power optimizers, or microinverters. Each inverter setup comes with upsides and downsides. Here's what you should know.

As the name implies, string inverters connect a set of solar panels, also called a string, to a singular inverter. The inverter will convert the DC electricity from every solar panel connected to that string. But if a solar panel in that string is partially shaded, blocked or facing maintenance issues, it jeopardizes the performance and efficiency of all the other panels on that string. To prevent this, many homeowners will also choose to install DC power optimizers with their string inverter. 

DC power optimizers are installed on each panel individually and take into account the performance of each panel in the string separately. This means that if one panel is shaded or shuts down, all the other panels will still perform normally. DC power optimizers are recommended if your roof is partially shaded or not at the best angle for catching sunlight. 

"With a microinverter, there's one for every panel, so it would be a big pain if you had to replace a bunch of microinverters because there might be potentially as many of them as you have panels," Kurchin said. "Whereas with a central string inverter, that would typically not be on the roof. So the labor and safety considerations of replacing it are not as arduous. That thing's going to last like 10 to 15 years. And then it'll probably have to be replaced only halfway or so through the lifetime of the panels." 

Note that certain manufacturers require the installation of DC power optimizers with their string inverters. String inverters are also usually cheaper than microinverters. However, installing DC power optimizers with your string inverter will cost extra. DC power optimizers and string inverters typically come with separate warranties too. 

Homeowners who choose to install microinverters will have a much different solar setup. Instead of one large inverter box that connects to multiple solar panels, a microinverter is, well, a "micro" inverter that gets installed on each individual solar panel in the array. Since microinverters operate on the panel level, they are good for complicated solar installations, partially shaded roofs or roofs that might not be an optimal angle for solar. Microinverters also allow for easier system expansion.

"It's much easier to expand your system later on," Kurchin said. "So for example, if you only have the money upfront to install panels on half the roof and you wanted to put up more of them later, it's a lot easier to add on more panels with microinverters. Whereas normally when you buy a system with the DC optimizers and the central string inverter, the inverter would be sort of sized to the system that you already have." 

Because microinverters are considered roof equipment, they also tend to be covered under warranty for much longer than string inverters. The industry standard for microinverter warranties is 25 years. However, because they are installed on the roof, they are harder to repair and replace. 

"The disadvantage for a homeowner about microinverters is that each microinverter is mounted behind each module up on the roof of your house. And when one stops working, you're gonna have to send someone up on the roof of your house into the middle of an array of modules," Roger French, a professor at Case Western Reserve University's department of material science and engineering, told CNET. "That's actually a big problem for lots of people." 

Choosing an inverter for your home can be tricky. In most cases, an installer will handle this for you. Along with selecting a reputable installer, there are a few other things to look for when choosing an inverter.

Knowing what kind of solar panels and equipment you want for your home is only one half of the battle. Finding the right solar installer for the job is the other half. Solar is a huge investment, and you want to make sure that your system is installed correctly the first time around. 

"I think the biggest decision a homeowner can make is who's going to install their system. So having certified companies with the right qualifications with a track record in the area, and you know they're going to install it correctly," Kristopher Davis, an associate professor of materials science and engineering at the University of Central Florida, told CNET. "And if there is a problem, they'll be around years from now so they can provide service."

When searching for a solar installer, look at their track record and how many solar projects they have installed. Try to find an installer that has experience working with the type of roof that you have and the type of install you're looking for. If you plan to have a solar battery installed, pick an installer that has experience with that as well. 

A reputable installer will conduct a roof inspection beforehand and an energy audit to find out what type of solar set up is ideal for your home. Your installer should also walk you through all your options and be able to answer all your questions clearly, no matter how difficult those questions might be. 

"I would defer to their track record. When someone's a brand new installer, that's when they make more mistakes. And if they've been installing a lot of systems for many years, that's one of the best things about them," French said. 

Certain installers will also offer a performance guarantee to make sure your system was installed correctly and is still operating correctly after a certain amount of time has passed. Davis says you should also see if the installer can help you understand how to monitor your solar panels. If there's a big drop in energy production, you'll want to know what the process is like if something goes wrong and who to contact. Davis says if your installer doesn't have answers for those types of questions, that's a red flag.

Weigh all your options and get quotes from multiple installers in your area for the best price possible. Getting a mix of quotes from national and local installers will give a decent price variety. 

Your solar inverter needs to be compatible with the rest of your solar panel system. Off-grid or partially off-grid systems are going to require a different type of inverter than one that is for purely on-grid purposes. Most solar inverters will fall into one of these three categories. 

Grid-tied inverter: Grid-tied solar inverters are the most common inverter type you'll come across. As the name suggests, these inverters require a grid connection to operate and are capable of pulling power from the grid as well as feeding power to the grid. However, if the power grid ever goes down, a grid-tied inverter will automatically shut off too, which leaves you prone to power outages even with solar panels. To avoid outages, a solar battery and additional equipment needs to be installed. Grid-tied inverters are normally cheaper than hybrid and off-grid options, too.

Hybrid inverter: A hybrid inverter is a solar inverter and a battery inverter combined into a single unit, designed to offer an on-grid and off-grid power solution. However, you can still install a hybrid solar inverter without a battery. Solar batteries need a battery inverter to be able to power your home. Some solar batteries on the market come with their own built-in (or integrated) battery inverter. But if a solar battery doesn't come with a built-in battery inverter, you'll need to install a compatible third-party one. A hybrid inverter could be an option in this situation. Just keep in mind that hybrid inverters are typically pricier than regular grid-tied solar inverters.

Off-grid inverter: An off-grid inverter is designed for off-grid solar panel systems. These draw power from solar batteries to operate and to keep the power on during the day and at night. This type of inverter cannot be connected to the grid and should only be installed if you have plans to live completely disconnected from the power grid. You'll likely also need multiple batteries to truly live free from the power grid. 

When it comes to inverters, size matters. It's important that your inverter is sized properly with your solar panel system to avoid efficiency and power reduction issues. Your inverter's maximum AC power output should match your solar array's maximum energy production (DC power). If your solar panel's DC energy production is greater than your inverter's maximum AC power output rating, it can result in solar inverter clipping, limiting how much energy is actually delivered to your home. You'd lose out on chunks of electricity generated by your solar panels. 

Your inverter's wattage should match the wattage of your solar panel system. If you have a 7,000-watt solar panel system, your inverter size should be at least 7,000 watts, too. But when it comes to solar products, you'll likely see kilowatts (kW) used as a unit of energy measurement more than watts. That's fine -- the same rule still applies with kW. If you have a 7 kW solar panel system, your inverter size should also be at least 7 kW (7,000 watts). Getting a solar inverter with a much larger wattage than your solar array can cause efficiency and performance issues. 

An installer will properly size your inverter with your solar panel system based on the size of your solar array and the amount of sunlight your home receives throughout the day. 

As with any expensive purchase, you'll want to know your inverter's warranty, along with the specifics on what costs are covered and what costs you'll be paying out of pocket. Most solar inverters come with a limited warranty. The limited warranty will typically cover five to 12 years (depending on the manufacturer). Most manufacturers will cover an inverter or part replacement under the limited warranty, butwill not cover the labor cost to install the part or the associated shipping fees. Shipping and labor costs are more likely to be covered under an extended warranty, which comes at an additional cost. These extended warranties can cover anywhere from 15 to 25 years. 

Make sure to carefully read through an inverter's warranty document to see what costs will be covered. 

Inverters with multiple components will typically come with separate warranties for each component. DC power optimizers are a component that is frequently purchased with string inverters, but since these are two separate components, the string inverter and DC power optimizers will likely have separate warranties. Roof equipment, like DC power optimizers and microinverters, will normally have longer warranty coverage than wall equipment. Twenty-five years is the industry standard for microinverter and DC power optimizer warranties. 

Inverter efficiency is a measure of how efficient your inverter is at converting your solar panels' DC electricity into AC electricity to power your home. The higher your inverter's efficiency, the less electricity you lose over time. However, it's important to note that an inverter's efficiency will never be 100%. This is because some energy is lost to heat or is used by the inverter during the conversion process. Energy can also be used to power the inverter when it's on standby.

Experts also say inverter efficiency does matter to a degree. But what matters more is choosing the right type of inverter, like string inverters or microinverters, and solar set up for your home

"With efficiency, I wouldn't go so far as to say it's a red herring, but generally pretty much all inverters nowadays are 95-plus percent efficient," Kurchin said. "So that's unlikely to be kind of a make or break for any real practical application."

There are two different inverter efficiency ratings to pay attention to: peak (maximum) efficiency and California Energy Commission (CEC) efficiency, with CEC efficiency being the more helpful of the two ratings. 

Peak efficiency: An inverter's peak efficiency (also known as maximum efficiency) rating indicates how efficient the inverter is at converting the solar input (DC) energy into home electricity output (AC) energy when it's operating at its optimal (or rated) capacity. In other words, this is a measurement of your inverter's efficiency when it's performing at its best. 

CEC efficiency: California Energy Commission efficiency is most commonly referred to as CEC efficiency and is a weighted efficiency rating that reflects the inverter's performance range across various DC input amounts. An inverter isn't always going to operate in "optimal conditions." You're going to have periods of indirect sunlight throughout the course of the day. CEC efficiency is a weighted efficiency rating that takes into account different load factors at different voltages, which gives you a more accurate representation of how efficient your inverter is actually going to be on an average sunny day. 

"The actual efficiency of your inverter is going to be some sort of weighted efficiency based on how much power is going into it at different times and at different efficiencies, at those different powers," Kurchin said. "And so the CEC efficiency rating is trying to get some sort of general estimate for that by making measurements of the inverter at different percentages of its rated power."

To get its CEC efficiency rating, the inverter is tested by a third-party, California Energy Commission-approved laboratory. Check out the CEC Solar Equipment List Program for a comprehensive list of CEC-tested products.

Europe also has a similar weighted efficiency rating called the "European efficiency rating." This rating has the same premise as the CEC efficiency rating, but weighs in different assumptions during the calculation. 

Your inverter is the central hub, or "brain" of your solar panel system. With the correct software in place, your inverter will be able to continuously collect data on your home's energy consumption and how much electricity your solar panels are producing. Most inverter manufacturers create an app that allows you to monitor this data. More advanced inverter software will usually include features that help users control their power loads, avoid time of use rates and store your energy data to help predict your monthly energy bill and ways you can save. Long story short -- the more ways you can control and interact with your solar panel system, the better. 

However, these apps are not without their flaws. Some solar monitoring apps can be buggy and might not always update you with your solar system's data when they're supposed to. Reading through user reviews on app stores can give you a decent understanding of what you'll be experiencing when using a specific solar app. 

The "best" solar inverter for your home depends less on the inverter manufacturer and more on what your home's specific energy needs are. Your solar panel system size and the conditions on and around your roof play vital roles in determining what type of inverter setup is best. Experts emphasize picking a solar installer with a good track record of the type of solar install you're looking for. 

Read more: Want something smaller than a whole-home solar system? See our picks for the best portable solar panels and solar generators.

What is the best solar inverter?

Experts told CNET that finding the best solar inverter isn't as important as finding a reputable and reliable installer who will source equipment that works for your needs. That said, CNET's pick for best solar inverter is the SolarEdge Home Wave Inverter.

How long do solar inverters last?

String inverters are typically under warranty for 10-12 years, and will most likely have to be replaced during the lifespan of the solar panel system, which is typically warrantied for 25 years and can last longer. Microinverters usually come with 25 year warranties.

Where should a solar inverter be installed?

Microinverters are installed with each panel up on your roof. String inverters are typically installed near ground level, which makes them easier to access for maintenance purposes.

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Best Solar Inverters of September 2023 - CNET

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