Microinverters convert the electricity directly under each module, string inverters centrally for the whole system. For the typical single-family home roof, the string or hybrid inverter remains the standard – reliable, cheaper, battery-friendly. Microinverters specifically play out their strength: on heavily shaded or angled roofs, where module-by-module conversion brings real extra yield. (As of: July 2026)
Key points in brief
- The difference is the place of conversion: centrally in the basement (string) or decentrally under each module (micro).
- Microinverters decouple the modules the strongest – a shaded module does not pull the others down with it.
- The price for this: higher costs per kWp and many devices on the roof – a service case there means roof access instead of a trip to the basement.
- Proven sequence for shading: first smart string planning, then power optimisers, only then microinverters.
- Whoever has or is planning a battery usually fares easier with the hybrid inverter.
What is a microinverter – and what does it do differently?
Every solar system needs the conversion of direct into alternating current – the task of the inverter. The only question is where it takes place.
With the string inverter, the widespread standard, it happens centrally: Several modules connected in series (a «string») deliver their direct current to a device in the basement or technical room that serves the whole system. With the microinverter, this task moves to the roof: Under each module (or each pair of modules) sits a small device that converts its electricity directly into alternating current. From the roof then comes no more direct current line, but grid-ready alternating current.
From this one difference – central or per module – follow practically all strengths and weaknesses of both concepts.
The direct comparison
| String inverter | Microinverter | |
|---|---|---|
| Conversion | central, one device | decentral, per module |
| Shading | Modules of a string influence each other | Modules completely decoupled |
| Monitoring | System or string overall | visible per module |
| Costs per kWp | lower | higher |
| Service case | one device, accessible in the basement | many devices, on the roof |
| Battery connection | simple (hybrid device) | more complex (AC-coupled) |
| Typical application | Standard single-family home roofs | heavily shaded, angled small areas |
Simplified comparison, as of: July 2026. The planning on the specific roof is decisive.
Where microinverters are really strong
Shading is their home game. In a string, the modules influence each other – if one falls into the shade, the chain suffers. Microinverters dissolve this dependence completely: Each module works for itself, the shaded one delivers less, all others unhindered onwards. On roofs over which a hard shadow wanders daily – chimney, dormer, neighbouring building – this is a real extra yield, not a brochure argument. The effect of shade and the countermeasures at a glance: Shading in solar systems.
Angled roofs profit doubly. Where small sub-areas point in three, four directions, string planning becomes tedious – too few modules per direction for clean strings. Module-by-module conversion turns the patchwork into a functioning whole; every area produces independently what it can.
The monitoring per module is a pleasant side effect: Failures and underperformance can be narrowed down to the individual module, instead of being searched for in a string comparison. For everyday life this is convenience, not a must – what the system really needs in operation is also achieved by good string monitoring.
The honest other side: What speaks against microinverters
The price. Many small devices together cost more than a central one – per kilowatt-peak the micro solution is noticeably above the string device. On an unshaded south-facing roof one buys this surcharge without ever seeing the equivalent value: Where there is no shade, there is nothing to decouple.
The service case takes place on the roof. The inverter is the component of the system that is typically replaced once in the life of the system – with the string device this is an appointment in the basement, done in hours. With the micro concept, the devices sit under the modules: A defect means roof access, possibly module dismantling, depending on the situation scaffolding. The manufacturers counter with long warranties, and individual failures only shut down one module instead of the whole system – but the effort per repair remains structurally higher. This trade-off belongs in every honest consultation, because it only shows itself in year ten, not on the day of sale.
Battery plans speak for the hybrid route. A battery storage unit docks most simply to a hybrid inverter – one device for system and battery. With microinverters, the electricity is already alternating current on the roof; a battery then needs its own AC coupling with an additional device. Feasible, but more complex – whoever is planning the battery or wants to keep it open should calculate this into the overall picture.
First plan, then technology: the proven sequence
The most important classification at the end, because it is often skipped in the sales conversation: Microinverters are the third answer to shading, not the first. The proven sequence:
1. Smart planning – Lay module placement and string division so that shaded areas form their own strings. Costs no additional technology and solves many cases alone. 2. Power optimisers – module electronics on the string device that makes individual modules more independent: the middle way for targeted problem areas. 3. Microinverters – the strongest decoupling for roofs where the first two levels are not enough.
Whoever offers you microinverters for an unshaded standard roof should be able to justify this sequence – «state-of-the-art technology» is not a justification, but a surcharge without a mandate. The reverse is also true: On the right roof, microinverters are not a gimmick, but the solution that turns a difficult surface into a good system.
The question of microinverters in our consultations usually comes with them from the internet – read somewhere, sounds superior, why don't you offer that to everyone? Our answer regularly begins on the roof instead of in the catalogue: Only the shadow progression over the day and the seasons shows whether there is a problem at all that module-by-module technology would have to solve. For most roofs in the region the finding is: cleanly planned strings are sufficient, the money is better invested in one, two additional modules. And then there are the other cases – the chimney in the middle of the south surface, the neighbouring house, the three small sub-areas – where we ourselves advise module-by-module optimisation. The technology is good; it just has to fit the roof and not the brochure.
Frequently asked questions
Are microinverters more reliable than string devices?
Both concepts are mature. The difference lies in the error pattern: If a string device fails, the system stands still – but the replacement in the basement is done quickly. If a micro device fails, only one module is missing – but the repair takes place on the roof. Reliability decides less here than the question of which error pattern you prefer.
Can I combine string and microinverters?
On the same roof fundamentally yes – for example micro devices for a shaded sub-area, a string device for the main area. This needs clean planning for connection and monitoring; whether it is worthwhile depends on the individual case. More frequent is the simpler solution: Optimisers for the problem modules on the string device.
Do I still need a central inverter with microinverters?
No – the conversion is completely done with the module devices; alternating current comes from the roof. But the remaining components of the system are still needed, from the connection to the metering and monitoring concept.
What happens in the event of a defect under the module?
The affected module fails, the rest continues running – the failure is visible exactly to the module in the monitoring. Roof access by the specialist company is needed for the replacement; depending on the situation with scaffolding or fall protection. Therefore the service question belongs in the purchase decision, not only in the warranty case.
Are microinverters worthwhile for small systems?
For very small or angled areas they can be the most practical solution – there string planning often fails due to too few modules per orientation. For the normal single-family home system without special shading, the string concept remains the more economical choice.
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Which technology fits your roof?
We assess shadow progression and roof geometry on site and quote the solution that your roof needs – string, optimiser or micro, with justification instead of brochure.
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Sources: Manufacturer documentation (string, hybrid and microinverters, general system concepts); empirical values from the planning and installation practice of ecoEn GmbH, Region Zurich.
Last updated: 9 July 2026 · Author: ecoEn editorial team
