What are the best solar inverters in 2021?
- Best micro-inverter: Enphase IQ7+
- Best string inverter: SMA Sunny Boy
- Best string inverter with optimizers: SolarEdge HD-Wave
- Best inverter for grid-tie + energy storage: Outback Skybox
We recently published our recommendations for our favorite off-grid inverters you can buy for solar applications.
It quickly became one of the most popular articles on our site. So now we’re back with its counterpart: a review of the best solar inverters you can buy for grid-tie systems in 2021.
These are the inverters you would use in a traditional home or office system – any property that has access to power lines and can connect to the utility grid.
We put together a video to highlight our picks. You can also keep reading for more detailed analysis, current prices and key product specs.
Here’s our review of the best grid-tied solar inverters you can buy on the market in 2021:
Best Grid-Tied Microinverter
Best String Inverter with Optimizers
Best Grid-Tied String Inverter
Best Storage-Ready Grid-Tied Inverter
Why Do I Need an Inverter?
If you’re just getting into solar, let me quickly explain what an inverter does.
The inverter is like the brain of your solar system. It manages the flow of power throughout your system.
When panels collect energy from the sun, they generate DC (Direct Current). But home appliances use AC (Alternating Current).
At its core, the inverter has a simple job: it converts captured DC power into usable AC power.
Beyond that basic functionality, some inverters have extra features that make them more suitable for specialty applications. Let’s take a look:
Best Microinverters for Grid-Tied Systems: Enphase IQ7+
- Wattage: 290W
- Peak Efficiency: 97.6%
- Individual Panel Monitoring? Yes
- Best for: starting with a small system and expanding in the future. Also great if you have multiple places to build on your roof and want to split the system into sub-arrays.
The concept of microinverters is simple: pair an inverter with every panel.
The benefits are fairly easy to understand as well. There are two cases where you should use microinverters:
- You want to start with a small system and be able to expand down the road.
- You want to monitor each panel independently.
In some ways, when you pair a microinverter with a panel, you’re creating a self-contained single-panel solar energy system. Each will produce power regardless of how many panels you have.
We recommend the Enphase IQ7+ Microinverter for these applications. As of the time of publication (January 2021), these are $147 apiece. You also need a mandatory Q Cable for each microinverter, which adds $18 per panel.
You’ll typically pair them with a panel ranging between 235 to 440 watts, which will cost you another $150-$225 or more depending on panel selection.
Each inverter and panel pairing works out to around $350 (fluctuating by ~$50 depending on which products you pick). This does not include the cost of mounting or wiring the system.
Recommended Panel Pairings For The IQ7+: Astronergy 335W or Mission Solar 310W
So how does the math look when you’re trying to build a full-sized system?
Let’s say it would take a $10,000 system to completely offset your energy bill, but right now, your budget is only $3,000.
If you want to cancel out a portion of that bill right away, you might get about 8-10 panels with microinverters on them. You’d start saving money on electric bills right away, and you can easily add on to it a few years down the road until you hit your target of 100% energy offset.
The ease of installation is another nice side benefit. Microinverters use standard AC wiring, which is cheaper and easier to work with.
In all, microinverters make it possible to get started with solar and build out your system at your own pace. But that scalability comes at a slightly higher price than other options.
If you have the budget to build a complete system from the start, we’d recommend going with a more cost-effective option: a string inverter.
Best String Inverter: SMA Sunny Boy
- Wattage: 7700W
- Peak Efficiency: 97.5%
- Individual Panel Monitoring? Not by default (you can add optimizers for extra cost, but you lose the Secure Power Supply feature by doing so.)
- Best for: complete grid-tied systems in full sunlight.
A string inverter is a single unit that hooks into a string of solar panels. Our recommendation in this category, the SMA Sunny Boy, is sized to support strings in the range of 6-14 panels.
String inverters are your least expensive option, and they thrive in the right conditions.
The main issue with string inverters is that when shade falls on one panel, the efficiency drop translates to the other panels in the string. So if you have 10 panels in a string, and one gets shade, all 10 will drop to the reduced output of the shaded panel.
But what if you have space to build a system that will never fall under shade?
If you have land with plenty of unobstructed space, this is going to be the cheapest and most effective inverter for most systems.
If you live on a city block with buildings or trees casting shadows on your panels…not so much. You’d never get close to the expected output from your system.
But if you’re sure you have enough room to build away from obstructions, go with the SMA Sunny Boy inverter. It’s a reliable string inverter that is far cheaper than other options assuming you meet the requirements.
Depending on the model, the Sunny Boy inverters have either 2 or 3 inputs, which means you’ll have either 2 or 3 strings of panels wired to your inverter.
The SMA Sunny Boy also comes with a neat feature: a 2000 watt Secure Power System (SPS). The SPS is a feature unique to the SMA brand.
The SPS acts like a small backup power source in case of outages. While it’s not a long-term solution, the SPS powers a dedicated 120v outlet that can power up to 2000 watts during the day if there is solar power available.
You can also buy optimizers and pair them with the inverter. This will help mitigate the shade problem, but as a tradeoff, you lose the SPS functionality.
It makes sense to add the optimizer if you previously built an SMA system, then needed to retrofit the array due to new obstructions. Adding optimizers onto the panels would be easier and more effective than ripping out and replacing your whole inverter.
However, if your goal from the start is to get the most output from a partially-shaded array, we would recommend a different inverter for that purpose.
Best String Inverter w/Optimizer: SolarEdge HD-Wave
- Wattage: 7600W
- Peak Efficiency: 99%
- Individual Panel Monitoring? Yes
- Best for: a broad variety of grid-tied solar applications. You get the convenience of centralized design, paired the flexibility of panel-level monitoring. It’s the best mix of features and price.
Our best-selling residential grid-tied inverter is the SolarEdge HD-Wave line, a string inverter with optimizers. The classic HD-Wave line received a major update in 2019 with the introduction of the SetApp feature, which allows you to program and monitor your system from a phone app (rather than on the LCD screen).
This is our go-to grid-tied inverter option because it offers the best of both worlds. You get the lower cost of a central string inverter combined with the individual panel monitoring offered by microinverters.
For that reason, it works in a broad range of applications. In most cases, it’s simply the best combination of features and cost you can find in a grid-tied inverter.
The system is shade-tolerant thanks to the optimizers attached to each panel. And it’s cheaper than microinverters once you scale to at least 8 panels (the minimum string size compatible with SolarEdge inverters).
In the end, SMA and Enphase are tailored to a specific application. The SMA Sunny Boy needs full sunlight, and Enphase microinverters are more appropriate if you start with a small system.
For other grid-tied applications, our default recommendation is the SolarEdge line. It’s the workhorse of the industry: nothing too flashy about it, just versatile, reliable and easy to use.
Our most popular size is the SolarEdge 7.6 kW HD-Wave inverter, but they come in a range of 3.0 kW to 11.4 kW options for residential systems, with higher capacity options available for commercial use.
Best Grid-Tied Inverter With Storage Capacity: Outback Skybox
- Wattage: 5000W
- Peak Efficiency: 97%
- Best for: grid-tied systems with energy storage, which protects against power outages and allows you to store power and use it later.
If you want to add battery backup to the mix, you’ll need a storage-ready inverter to manage your system.
Aside from protecting against emergency outages, energy storage has another purpose. You can take control of your power, storing it for later or sending it into the grid.
This is used in areas where the utility bills have time of use (TOU) charges or residential demand charges. Energy storage allows you to store and consume the power your generate. You can even sell excess energy back to the utility for a profit.
Our recommendation in this category is the Outback Skybox. It’s our favorite battery backup option because it checks all the boxes:
Ease of Installation
All components (inverter, remote control, breakers/load center and PV inputs) are included in one unit. Since all connectors for the PV array, the utility grid, and a backup generator are present in the main console, you only have to mount a single unit during installation.
This makes it far easier to install than other systems, which require you to mount and wire anywhere from 3-6 different components together for interconnection. The ease of installation is one of the Skybox’s key selling points.
It works with any standard 48V battery bank. It’s more flexible than the competing StorEdge option from SolarEdge, which is only compatible with a single battery (the LG Chem).
Backup Generator Input
It has an input for a backup generator, in case you need to build a hybrid generator + solar system.
Works Without Batteries As a Standard Grid-Tie Inverter
It allows you to start as a pure grid-tie system and add batteries later without any additional parts or configuration changes. Other products don’t have this flexibility. Outback’s own Radian system requires
The Skybox’s versatility makes it our preferred pick for energy storage systems.
An Alternate Energy Storage Pick: Magnum MicroGT
Another good pick for storage-ready inverters is the Magnum MicroGT. It provides backup power
However, the MicroGT lacks the functionality to offset time-of-use charges and sell energy back to the grid. It also does not comply with the new smart inverter requirements in California and Hawaii.
These drawbacks prevent us from recommending the MicroGT all situations. The Skybox is simply a more complete and versatile product.
This article was updated on 1/2/2021. For our most current prices, take a look at the inverters page in our shop.