This is probably the most common technical question I get from people planning a solar installation: should I get microinverters or a string inverter? And the honest answer is “it depends” — but let me actually explain what it depends on, because most guides online just list pros and cons without telling you when each one wins.

The basics in 30 seconds

String inverter: All your panels wire together in series (a “string”), and the DC power flows to a single inverter box (usually mounted on a wall near your switchboard) that converts it to AC power for your home. One inverter handles all the panels.

Microinverters: Each panel gets its own tiny inverter mounted underneath it. Conversion from DC to AC happens on the roof, panel by panel. The most common brand in Australia is Enphase.

Power optimisers (the hybrid option): Each panel gets an optimiser that conditions the DC power, but conversion to AC still happens at a central inverter. SolarEdge is the main player here. It’s kind of a middle ground.

When string inverters win

Clean, unshaded roof with consistent orientation. If all your panels face the same direction with no shading issues, a string inverter is perfectly adequate. The efficiency is comparable to microinverters, the upfront cost is lower, and you’ve got one device to monitor and maintain.

Budget is the priority. A string inverter system is typically $1,000-2,500 cheaper than a comparable microinverter setup. If your roof is straightforward, that’s $1,000-2,500 better spent on a bigger system or saved for a future battery.

Large systems. For commercial or larger residential systems, string inverters (especially three-phase models) are more practical. You’re not putting 40 microinverters on a warehouse roof.

Good string inverter brands for Australia: Fronius (my personal favourite for build quality and monitoring), Huawei (excellent value), GoodWe (budget-friendly, solid), and SMA (German engineering, premium price).

When microinverters win

Complex roof with shading. This is the big one. With a string inverter, if one panel is shaded, it drags down the entire string. With microinverters, each panel operates independently. If your neighbour’s tree shades two panels in the afternoon, only those two panels are affected — the rest carry on at full power.

Multiple roof orientations. If you’ve got panels on north AND west, or split across several roof sections, microinverters let each panel optimise independently. A string inverter would need multiple strings with potentially different MPPT channels, and the design gets complicated.

Gradual expansion. Want to start with 10 panels and add more next year? Microinverters make this trivial — just add more panels with more microinverters. With a string inverter, you need to ensure your initial inverter is sized for the expanded system, and string lengths need to be balanced.

Panel-level monitoring. Microinverters give you production data for every single panel. If one panel underperforms, you know exactly which one. With a string inverter, you see total system output but can’t isolate individual panel performance without additional equipment.

The reliability question

String inverter advocates point out that a single inverter is a single point of failure — if it dies, your whole system stops. True, but modern string inverters from quality brands have 10-15 year lifespans, and replacement is a single service call.

Microinverter advocates argue that if one micro fails, only one panel is affected. Also true, but servicing a micro on your roof requires a roof access and is more expensive per unit. And if you’ve got 20 micros, the statistical probability of at least one failure over 25 years is higher.

In practice, both technologies are reliable enough that failure rates shouldn’t be a primary decision factor. The CEC’s data on warranty claims shows no dramatic difference between the two in Australia.

What about power optimisers?

SolarEdge’s model gives you panel-level optimisation and monitoring (like micros) with a central inverter for DC-to-AC conversion (like a string system). It’s a genuine middle ground.

The downsides: SolarEdge inverters and optimisers must be used together (vendor lock-in), and the total cost is usually between a pure string and microinverter setup. Also, the optimisers add points of failure on the roof.

My recommendation

If your roof is straightforward — single orientation, minimal shading — go with a quality string inverter (I’d pick Fronius for most residential installs). Save the money for a battery or a bigger system.

If you’ve got shading issues, multiple orientations, or you want to expand later, microinverters (Enphase IQ8+ series) are worth the premium. The production gain in real-world conditions can easily justify the extra cost.

Don’t agonise over this decision. Either technology will serve you well for 15-25 years. The difference in lifetime value between a good string inverter system and a good microinverter system is typically less than 5% on a straightforward roof. Focus your energy on choosing a good installer instead.