Which Are The Best Solar Inverters?
Last Updated: 17th Mar 2022
So you’ve got quotes for a few different solar power systems. Everyone says they sell the best solar inverter – no surprises there. So how do you decide what brand and model to select in 2022? Our solar inverter reviews can help you choose what’s best for you – these reviews offer unbiased information based on the feedback of thousands of Australians using different makes and models.
However, it’s good to first have some background information on what this important device does, the major manufacturers that produce them and various other aspects to consider. This guide will provide you with all the information you need in 2022 to pick the best inverter for your requirements.
What Is A Solar Inverter?
A solar inverter is a box of electronics through which all the all the solar power produced by your panels will pass through before being transported to your home for use by your appliances; or in the case of surplus energy generated, to the mains grid. It really is the workhorse of the system.
The device also contains important safety shutdown electronics such as Anti-Islanding Protection.
For this and other reasons, it very important you choose a solar inverter up to the job and one that offers the best performance for your money.
Recommended Solar Inverter Brands
I’m guessingyou don’t know one brand of solar inverter from another – you certainly aren’t alone. The simplest, quickest way I can think of how to describe how each brand stacks up is to compare them to cars – because I’m also guessing most of you will know the difference between a Mercedes, a Ford and a Hyundai.
If you’re in a hurry and you don’t want to “geek out” over the technicalities– this chart I created will teach you enough to be dangerous when talking to shonky sales people or evaluating quotes:
If Solar Inverters Were Cars…
You can read more about the above brands (and many others), along with feedback from Australians who have had them installed in our solar inverter reviews section.
Towards the end of this page is a chart containing solar inverter brands I recommend in 2022.
Now let’s get technical.
If after all that you’re still yearning for a deeper understanding, then continue reading…
Types Of Solar Inverters
The following describes each type:
a) String Inverters
This is the most common type of inverter for residential use. All the solar inverters above (apart from Enphase) are string inverters. On a residential solar power system you generally have one per installation. It is called a string inverter because you connect strings of solar panels to it. These are wall-mounted, usually close to your meter box.
You can compare inverters side-by-side here.
b) Central Inverters
These are massive inverters used for solar systems in the hundreds of kilowatts or even megawatts of capacity. They look like big metal cabinets and can handle up to megawatts of capacity per enclosure. You won’t find these as part of home installs; they are only used for large commercial installations or utility scale solar farms.
Microinverters are tiny solar inverters about the size of a paperback book. You need one per solar panel. You can read about the advantages of microinverters here –the main one being is they optimise each panel individually, delivering more energy. Microinverters can be particularly useful if you have partial shade conditions, although some more recent string inverters are proving to be handling these conditions better than they used to. The best microinverter brand is Enphase, in my humble opinion.
d) Optimised string inverters
Optimiser based systems provide similar performance benefits to microinverters, but by using a slightly difference technology. An optimiser system requires a string inverter, but you then attach optimisers on the back of the solar panels, optimising each panel’s output under a variety of conditions.
Huawei and SolarEdge optimisers require you to optimise every panel in an array, but Tigo brand optimisers don’t (and are inverter agnostic), which keeps costs down. The Tigo option is particularly handy if you only have a couple of panels impacted by shade.
e) Hybrid Inverters
Also known as multi-mode inverters, a hybrid inverter enables you to plug batteries into your solar power system. The hybrid inverter interfaces with the battery using a technique called ‘DC coupling‘, and its electronics coordinate the charging and discharging of the battery.
There is a fairly limited choice of hybrid inverters on the Australian market right now, but the range will grow as battery storage becomes more popular. We’ve listed all the makes and models we know about on this hybrid inverter comparison table. Check it out if you are considering buying batteries with your solar power system.
f) Battery inverters
If you want to retrofit batteries to your solar power system, or simply keep your battery system separate from your solar panels (i.e. not going through the same inverter), then a separate battery inverter is a good (but expensive) choice. This simply converts your battery power into 230V AC and feeds it into your switchboard instead of grid power where possible.
What To Look For In A Good Solar Inverter
a) Can it be used in Australia and is it approved?
The first thing to look for when choosing a solar inverter is to see if it complies with the relevant Australian Standard (AS4777). You can quickly do this by checking out the Clean Energy Council’s approved products list.
All grid connected solar inverters certified for Australia should be on this list. If one you’re considering isn’t – don’t buy it (unless you live for danger!). The other reason for buying a solar inverter on the approved products list in the case of a full solar power system purchase is in order for your system to be eligible for Australia’s major solar subsidy, it must be on the list at the time of installation.
It’s also worth looking at the company behind the product – how long have they been around and what is their expertise?
b) How much should I pay in 2022?
This is a difficult question to answer, as grid connected inverters are mostly offered as part of a solar power system package. This component can represent around 20% of the cost of a system.
5kW solar inverter costs start at $1,000 for budget, single-phase models (e.g. Sungrow) and up to $2,000 for the premium single-phase models (e.g. Fronius or SMA).5kW is the most common size and can accept up to 6.6kW of panels. I explain more about this below.
If you want a 3-phase, 5kW inverter you should add about $400 to those prices.
But whatever you do,never buy the cheapest solar inverter on the market! The really cheap products have no chance of lasting 15 years plus in Australia. Trust me on this. It is difficult and expensive to design and manufacture a good solar inverter that will endure; particularly in Australia’s often harsh conditions. Never buy a bottom of the range product from a no-name brand. It is false economy as it just won’t last (rather like the companies selling them!).
c) What is the best solar inverter size (capacity) to buy?
There is often some confusion around this question.
In general, at a minimum the inverter needs to be able to handle the maximum power that your solar power system can generate. That usually means that if you want a 5kW solar power system, you get 5kW of panels and a 5kW solar inverter to suit. Simple eh? Actually, it can get a little more complicated than that. Let me explain.
Because of system losses in the panels, your solar inverter can actually be rated at up to 25% less (in AC kW) than your panel array – in some situations.Confused? So were a number of installers for some time! The Clean Energy Council guidelines for solar inverter sizing changed a while back, and I provide a detailed explanation of when ‘undersized’ inverters are allowed here.
A final word of caution:Be aware that solar inverters are rated in “DC input” and “AC output” terms. Make sure yours is also rated to suit the output of your solar panels in DC! (The previous link explains how to check this)
Some retailers will offer you a larger solar inverter so you can add extra panels at a later date. Before making a decision to buy one of these, you need to consider the following:
Solar panel technology is changing so rapidly that your current solar panels may not be available when you want to upgrade. Your inverter may not be able to accommodate the mismatch of solar panels, which may mean you’ll need to buy a new one. A way to overcome this potential problem is to perhaps consider a multi-string or a MPPT expandable solar inverter (see below).
In general, the best advice is to install as many solar panels as you can afford (and fit on your roof), and purchase a solar inverter to suit the maximum power of the system.
What about the physical size of the solar inverter?
Grid connected inverters come in a variety of shapes, sizes and weight. The smallest string inverters are around the size of a large briefcase. The larger are around the size of a small travel case.
They are generally located as near as practicable to your electricity meter and should always be located in the shade for best performance. Note that this can also be a requirement of warranty. If you don’t have a suitable shady spot, then you should have a simple shade cover made for it.
The best advice is to have a look at the solar inverter (or check out its specification sheet) and see whether it will fit near your electricity meter and what it will look like when installed.
d) Is it weather-proof?
Most grid connected inverters are weather-proof (generally IP65 rated) so they can be located in areas that may have some exposure to the elements. Other solar inverters are not weather-proof and may require the addition of a weather-proof cage (at extra cost to you) if the inverter is to be exposed to weather.
As a general rule, your solar inverter is a box of sensitive electronics and the better it is protected from heat and weather, the better it will perform and the longer it will last. It can also be a condition in the warranty that the unit is not installed where it will be subject to direct sunight.
Check these aspects on the specification sheets or ask your retailer where they intend to install your solar inverter.
e) How good is the warranty?
Typically, grid connected inverters have a lifespan ranging from 10 to 20 years. You should expect most good quality units to last 10 years minimum.
Solar inverters have warranties ranging from 5 to 12 years with an increasing number of manufacturers offering pay for service warranty extension. Most retailers are now offering 8 to 10 years warranty. Obviously, the longer the warranty the more protection you have.
Some manufacturers (like Fronius) are offering a “5 + 5” year warranty – where parts and labour are covered under warranty for the first 5 years, but only parts are covered for years 6-10 – so if your inverter conks out in year 7, you’ll need to pay around $200 in labour costs to replace the unit.
So check out the warranty of the unit and balance this against other features of your system to help you make an informed decision as to which is the best solar inverter for you.
f) Is the inverter expandable?
This is an important consideration if you’re intending to expand your solar power system in future.
The best solution at present would be to consider a multiple MPPT (Maximum Power Point Tracking) inverter. These solar inverters have multiple MPPT trackers allowing you to add additional solar PV arrays at a later date or to install arrays at different orientations. This will enable you to easily add a new string of panels (even if the new panels are not exactly the same as the original modules) to your current system.
Some solar panels have a small MPPT inverter attached to the rear of the module, typically called micro inverters. These potentially enable different models of solar panel to be incorporated in the same solar power system, overcome shading issues and make individual solar panel monitoring possible.
g) What about the display?
Most solar inverters have display lights indicating whether the unit is on, off or in standby. They can also have digital displays (often scrolling displays) that indicate someor all of the following information:
Some of this information (e.g the total amount of energy generated) is also available on your meter.
Some meters also offer a data-logging feature enabling you to download information to a computer, or transmit it over Bluetooth or your Wi Fi network. This means you can see your power information on your PC, smartphone or on a special in-home display.
I personally don’t want to look in the meter box (or wait for the bill) to see if my system is performing properly. I want to have a remote monitor in the house that I can check every day. So I think remote monitoring / data logging is a must.
If your supplier wants to charge you more than about $250 for remote monitoring, then you may want to consider doing it yourself.
h) How efficient is a grid connected inverter?
Inverter efficiency is a measure of how well a device converts the electricity it receives from the solar panels into power available to your home or to export to the mains electricity grid. Most grid connected transformer based solar inverters (very, very few of these are sold these days) have an efficiency of around 93% or better, while transformerless devices are typically around 95% or better.
Efficiency would only be a factor if two similar solar inverters had significantly different efficiency.
How To Spot A Bad Solar Inverter
Most solar inverters supplied by reputable retailers in Australia are OK. But there are some horrible devices that have somehow manage to pass Australian compliance testing.
Before you consider buying a very cheap solar inverter – check out my ever growing list of solar inverter reviews. These reviews are submitted by Australians who have owned the inverter for at least 12 months. If there are lots of 1 and 2 star reviews, this usually means the components are failing in the first 12 months. Not a good sign!
Also take a look at my solar inverter comparison table that compares features of lots of popular brands and models available in Australia.
It’s also worth checking some of the forums (such as Whirlpool) that discuss such topics.
Note: walk away if there is no written warranty offered on the solar inverter or no specification sheet is supplied. Make sure the organisation issuing the warranty has an Australian office – you don’t want to be calling Shanghai (or Munich) to get a new one!
Best Solar Inverters In 2022
The following chart shows solar inverter brands I recommend in 2022, the best in each category ranging from “budget” models on the left, to top-of-the-line on the right. See the criteria I based these recommendations on.
Early in 2022, I also asked installers in the SolarQuotes network their opinion, both in terms of high-end and budget products. Find out what they voted the best solar inverters in 2022 here. These are products they would be happy to install on their own homes.
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