The Best Grid-Tied Inverters for Solar Power Systems (2018 Edition)

The Best Grid-Tied Inverters for Solar Power Systems (2018 Edition)

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We recently published our recommendations of 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 grid-tied inverters you can buy in 2018.

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 2018:

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

  • Price: $186 apiece, which includes a mandatory Q cable for each panel. Total cost comes to 78 cents/watt.
  • 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:

  1. You want to start with a small system and be able to expand down the road.
  2. 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 Microinverter for these applications. As of the time of publication (September 2018), these currently range from $145-$215 apiece. You would pair them with a panel ranging up to 300 watts, which will cost you another $250+.

Each inverter and panel pairing works out to around $450 (fluctuating by ~$100 depending on which products you pick). This does not include the cost of mounting or wiring the system.

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 5-6 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

  • Price: $1775 (23 cents/watt)
  • 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

  • Price: $1475, plus mandatory P400 optimizers at $67 per panel. Works out to 41 cents/watt for a 24-panel system.
  • 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 line, a string inverter with optimizers.

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: SolarEdge StorEdge

  • Price: $2575, plus mandatory P400 optimizers at $67 per panel. Works out to 55 cents/watt for a 24-panel system.
  • Peak Efficiency: 98%
  • Individual Panel Monitoring? Yes
  • Best for: grid-tied systems with energy storage, which protects against power outages and allows you to store power and use it later.

Our last recommendation is the SolarEdge StorEdge inverter system. It’s a grid-tied inverter that is configured to work with energy storage. The StorEdge inverter is available in two sizes: 3.8kW and 7.6kW. It works with SolarEdge optimizers and has all of the same features as that system.

If you want to add battery backup to protect against power outages, you’ll need a storage-ready inverter to manage your system.

Energy storage systems have been gaining steam in recent years. In California (the state we call home), 20% of all grid-tied solar systems included an energy storage solution.

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 either time of use (TOU) charges, residential demand charges, or where the utility won’t buy your power.

Many utility providers charge higher rates during peak usage periods (typically evenings, when everyone is home from work or school). With a storage solution, you can store energy you generate for use during peak periods.

You can even sell excess energy you generate back to the utility company for a profit. This solution is popular in areas with unreliable power grids and variable utility rate plans.

The great thing about the StorEdge system is that you can expand into energy storage at any time. It works as a standard grid-tied inverter, and if you choose to add batteries later, it can easily adapt into a storage-ready inverter by adding 1 or 2 of the LG Chem RESU10H batteries.

Another good pick for storage-ready inverters is the Magnum MicroGT. It provides backup power like StorEdge does, but in microinverter form. It’s also configured to work with a broader range of batteries, whereas the StorEdge limits you to one battery (the LG Chem).

However, the MicroGT doesn’t comply with rapid shutdown requirements in California and Hawaii, which prevents us from recommending it in all applications. But it’s definitely a strong contender.

These are both great picks if you need energy storage now, or think you’ll opt into that choice down the road.

This article was updated on 10/2/2018. For our most current prices, take a look at the inverters page in our shop.

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