Once you’ve grasped that the inverter is the brain of your solar system, the next question is which kind of brain — because there are three different architectures, and the choice has a real effect on how much power you’ll actually harvest. The good news is that one factor decides it more than any other: shade. How much your roof gets, and where, is the lens that sorts the three options. Here’s how they differ, and how to choose between them without over- or under-paying.
String inverters — the cheapest, default option
In a string setup, all your panels are wired together into one or more “strings” that feed a single central inverter.
- Cheapest and simplest, and the most common choice in New Zealand.
- The weakness: panels in a string perform as a group. If one panel is shaded, dirty, or faulty, it can drag down the output of the whole string — like a group walking at the pace of its slowest member.
- Best for simple roofs with little or no shade, where every panel gets clear sun and there’s nothing to drag the string down.
Microinverters — the best shade tolerance
Instead of one central unit, a microinverter setup puts a small inverter on each panel, so every panel operates completely independently.
- Best shade handling — a shaded or underperforming panel only affects itself, not its neighbours. On a roof where shade moves across the array through the day, this can mean noticeably more total generation.
- Panel-level monitoring (you can see each panel’s output) and usually 25-year warranties matching the panels.
- The most expensive option upfront.
- Best for complex, partly shaded, or multi-orientation roofs — anywhere panels face different directions or catch shade at different times.
Power optimisers — the middle ground
Optimisers blend the two ideas: a small device sits on each panel (giving per-panel benefits) but they still feed one central string inverter.
- Better shade handling than a plain string setup, with panel-level monitoring — much of the microinverter benefit.
- Cheaper than full microinverters.
- The central inverter remains a single, easily replaceable component (unlike microinverters, which are spread across the roof).
- Best for roofs with some shade or multiple angles, where you want better performance and monitoring than a plain string system but don’t want to pay for full microinverters.
How to choose
Strip it back to your roof:
- Simple, sunny, single-orientation roof: a quality string inverter is the cost-effective, sensible choice. Don’t pay for shade handling you don’t need.
- Shaded or multi-angle roof: microinverters (best) or optimisers (good value) will recover meaningfully more power than a string setup that’s being dragged down.
- Want panel-level monitoring without microinverter cost: optimisers are the natural middle ground.
The two mistakes to avoid are opposite ones: don’t over-pay for microinverters on a clear, unshaded roof that a string inverter would serve perfectly — and don’t let an installer put a plain string system on a genuinely shaded roof, where it’ll quietly underperform for 25 years. Match the architecture to the shade.
The verdict
Three ways to convert your solar, and shade is the deciding factor: string inverters are cheapest and ideal for clear roofs but suffer when any panel is shaded; microinverters handle shade best and monitor each panel, at a premium; optimisers sit in between. Work out how much shade your roof really gets, then pick the setup that matches — paying for shade tolerance where you need it, and saving where you don’t.
Get a free assessment and we’ll match the architecture to your roof.
Sources: Inverter architecture, shade behaviour, and warranty data per 2026 industry references. Figures vary by product and installer.