What is an Inverter?

The job of a solar inverter is to convert the direct current (‘DC’) from the solar panels into alternating current (‘AC’) used in your home and the grid (refer to the appendix for more detail on DC vs AC). The inverter also generally acts as the overall monitoring system for your solar giving you detailed statistics, through a mobile app, on how much power your solar system is generating, how much power your home is using and how much power is being sent to or drawn from the grid.

Types of inverter

There are two main types of inverter; a string inverter and microinverters. String inverters sit on the wall of your house
where as micro-inverters sit under each solar panel. String inverters make up the vast majority of the solar installations
as they are more cost efficient than micro-inverters and easier to maintain and access. As discussed earlier generally
one standard home string inverter can support up to 6.6 kW of solar panels (although larger inverters are starting to hit
the market).

However, the downside of string inverters is that if one panel in the ‘string’ is under performing due to shade or dirt then all panels are reduced to the lower level of performance. This is not an issue for micro-inverters. Think of the comparison
to your old Christmas tree lights – if one light goes out, they all go out (string inverter) vs new modern LED lights – if one
goes out the rest stay on (microinverter). So, if your roof is prone to shade then you may want to consider microinverters.

An alternative, and likely cheaper, solution to micro-inverters is to add ‘optimisers’ to a string inverter. This has the same
effect as a micro-inverters, i.e. if one panel in the string is under performing, then other panels will not be impacted.
I use a SolarEdge inverter combined with SolarEdge’s optimisation system; SolarEdge is one of the few companies
in the market to offer both inverters and optimisers.

Takeaway – If you are on a budget and your roof has no shading then a simple string inverter should suffice. However, if your budget can stretch, or your house is prone to shading, then you should consider micro-inverters or
optimisers.

What brand inverter is best?

String inverters typically range from $1,000-2,500, with the more budget brands like GoodWe and Sungrow being at the bottom of the range and more premium brands like SolarEdge. Enphase and Fronius being at the top end of the range. I have personally gone with SolarEdge for the systems I have installed but I have heard and read good things about
GoodWe and Sungrow if you are on more of a budget.

Ensure that whatever inverter you choose has Wi-Fi connectivity and a good mobile app from which you can monitor the performance of your system and the consumption of power from solar and the grid.

The team from Solar Quotes have also done a great job summarising the inverter manufacturers. As to have the team from Clean Energy Reviews.

As a minimum you should check that the inverter you are thinking of buying has been approved by the Clean Energy Council so you can be sure it meets stringent safety requirements and also qualifies for a STC rebate.

Takeaway – Once you have a quote for a solar system compare the inverter in your quote to a third party source like Solar Quotes or Clean Energy Reviews, or other more well respected sources, to ensure what the salesperson is telling you reflects reality.