The inverter question trips up a lot of buyers. Most installers quote a standard string inverter because it's simpler and cheaper. In many situations, that's absolutely the right call. But there are cases where paying more for microinverters or DC optimisers genuinely pays off.
How a String Inverter Works
A string inverter takes DC power from a "string" of connected panels and converts it to AC power for your home. It's a single unit, usually wall-mounted near your switchboard, and it's the most common setup in Australian homes.
The limitation: the whole string performs at the level of its weakest panel. If one panel is shaded, dirty, or slightly underperforming, it pulls down the output of the entire string. It's like having a multi-lane motorway where a breakdown in one lane slows the whole road.
How Microinverters Work
Microinverters are small inverters — one per panel, attached to the underside of each panel on the roof. Each panel operates independently. Shade on one panel doesn't affect the others. If one microinverter fails, only that panel's output is lost — the rest of the system keeps running normally.
The leading brand is Enphase, which dominates the Australian microinverter market. Enphase microinverters carry a 25-year warranty — matching the panel warranty, which means no mid-life inverter replacement cost.
The trade-off: microinverters cost roughly $1,000–$2,500 more than a string inverter for a typical 6.6kW system.
DC Optimisers: A Middle Path
A third option — DC optimisers (like those from SolarEdge) — sit behind each panel to independently maximise each panel's output, then feed into a central string inverter. You get most of the shade-handling benefit of microinverters with a slightly lower upfront cost than a full microinverter system. The SolarEdge HD-Wave inverter with power optimisers is a popular mid-tier option in Australia.
When a String Inverter Is the Right Choice
For most Australian households, a quality string inverter (Fronius, SMA, Sungrow) is the right answer. It's proven technology, well-supported, lower upfront cost, and performs excellently on unshaded roofs.
Choose a string inverter if:
- Your roof is mostly unshaded throughout the day
- All your panels face the same direction
- Budget is a primary consideration
- You're adding a battery that integrates well with the inverter brand
When Microinverters or Optimisers Are Worth the Premium
Spend the extra money if:
- Partial shading: If trees, a chimney, a dormer window, or a neighbour's building shades part of your roof at any time of day, microinverters or optimisers will genuinely improve your output and payback.
- Multiple roof orientations: If you want panels on north, east, and west faces at the same time, microinverters handle mixed orientations better than string systems.
- Long system life focus: The 25-year microinverter warranty eliminates the ~$2,000 inverter replacement cost at year 12. For a set-and-forget installation, this matters.
- Panel-level monitoring: If you want to track each panel's performance individually (useful for catching faults early), microinverters with Enphase Enlighten provide this natively.
The Honest Recommendation
Don't let anyone upsell you on microinverters if your roof is shading-free and straightforward. But if you have any shading, or your panels will face multiple directions, the extra cost earns its keep. Get a shading analysis done as part of your quote — a good installer will model the impact and show you whether the upgrade is financially justified.
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