Comparison

Solar String Inverters vs Microinverters

String inverters convert DC from a series of modules. Microinverters convert at each module. Compare shading, layout, monitoring and cost.

Electrical & Power · Last reviewed October 17, 2026

Short answer: a string inverter is often the lower-cost choice for a simple, unshaded roof with one orientation. Microinverters, or a string inverter with module-level optimizers, help when the roof is shaded, has several orientations or may be expanded later.

	String inverter	Microinverter
How it works	Modules in series feed one inverter, often high DC voltage	Each module has its own inverter, with AC wiring on the roof
Shading and mismatch	The string follows its weakest module, unless optimizers are added	Each module operates independently
Roof layout	Strings are best with similar tilt and orientation	Flexible, with different orientations and lengths
Monitoring	System or string level, module level with optimizers	Module-level data as standard
Maintenance access	Inverter is at a convenient place, one device to service	Devices are on the roof, so service means roof access
Expansion	Limited by the inverter size and the string design	Add modules one at a time
DC voltage on the roof	High, with rapid-shutdown requirements	Low DC, with the AC trunk cable on the roof
System cost	Lower cost per watt in many systems	Higher cost per watt, which may be offset by extra energy where shading is present
Failure effect	An inverter fault stops the whole array	A fault affects one module

How to choose

Look at shading through the year, using a site survey or a tool. Meaningful shading favors module-level electronics.
List the roof planes and orientations. Several planes complicate strings.
Think about expansion and the future of the roof, including replacement.
Compare installed cost and estimated energy, not only the inverter price.
Check the code requirements for rapid shutdown and the warranty terms of each option.

Common mistakes

Choosing microinverters for a simple unshaded roof without checking whether the extra cost pays back.
Choosing a string inverter for a heavily shaded roof, then losing energy to mismatch.
Not planning access for inverter replacement, either on the roof or at the wall.
Forgetting that string voltage must stay within the inverter limit in cold weather.

Related tools and labs

Calculators, labs and simulators are part of the All-Access Pass.

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Questions

Are microinverters more reliable?

They remove a single point of failure, but there are many more devices on the roof, in heat. Warranty terms and the maker track record matter more than the topology.

What are power optimizers?

DC devices at each module that let a string inverter work with module-level control. They are a middle option between string and microinverters.

Educational material. Examples use simplified, hypothetical inputs and are not a design, a construction document or professional engineering advice. Confirm requirements with the codes and standards adopted where the work is built and with a licensed engineer.

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