String inverter vs microinverter: how to choose the best architecture for your customer's project

There is no absolute "best" architecture — there is the best one for that roof, that budget and that customer. Choosing between a string inverter and microinverters is a technical and commercial decision at the same time. This guide organises the criteria so you can defend the choice with arguments, not guesswork.

How each one works

With a string inverter, several modules are wired in series into a string that delivers direct current to a single central inverter. It is the cheapest architecture per watt and dominates projects with clean, well-oriented roofs. A microinverter converts DC to AC at each module (or every two). That brings independence: one module's performance does not drag the others down. There is also the middle path of the power optimizer, which keeps a central inverter but performs MPPT per module.

When the microinverter is worth it

Microinverters shine on roofs with partial shading (chimneys, water tanks, trees), multiple orientations and in residential projects that value safety (no high-voltage DC on the roof) and module-level monitoring. They also make future expansions easy — just add another module plus micro. The cost per watt is higher, but generation and longevity can make up for it.

When the string inverter is the right choice

For large roofs with a single orientation, no shade, and for commercial and industrial projects, the string inverter delivers the best cost-benefit and keeps maintenance centralised. In large systems, the saving per watt is decisive. Use the technical comparison of the three architectures to explain the differences to the customer.

String vs microinverter: side-by-side