String inverters, microinverters or optimisers: which is right?

If the panels are the muscle of a solar system, the inverter is the brain. There are three common approaches, and which is right depends on your roof and your budget.

String inverters

The traditional setup: your panels are wired together in a ‘string’ that feeds a single inverter, usually mounted on a wall. They’re cost-effective, reliable and well-proven — the default for a simple, unshaded roof where all panels face the same way. The catch: because panels are linked, shading or a problem on one panel can drag down the whole string.

Microinverters

Here each panel gets its own tiny inverter. Every panel works independently, so shading on one doesn’t affect the rest, and you get panel-level monitoring. They shine on complex roofs, multiple orientations, or where shading is unavoidable. They cost more, but for the right roof they earn it.

Power optimisers

A middle ground: optimisers sit on each panel to manage it individually, but still feed a central inverter. You get much of the shade-tolerance and panel-level monitoring of microinverters, often at a slightly lower cost.

How to choose

• Simple, unshaded, single-orientation roof? A string inverter is usually all you need.
• Shading, dormers, or panels facing different directions? Microinverters or optimisers will produce more.
• Want panel-by-panel monitoring? Microinverters and optimisers give it; string inverters give string-level.

There’s no single ‘best’ — only the best fit for your roof. A good designer recommends based on your situation, not just what they always fit. If you want an independent view, that’s what we’re here for.