Micro Inverter vs String Inverter in India

Most people in India tend to ignore the inverter brand and type and just go for the solar panels. That's a mistake. The inverter determines how much of the energy generated by your panels is utilized in your home, and the type of inverter you select (micro inverter vs string inverter) will impact your system's cost, performance and long-term operation for the next 20+ years.

What Is a String Inverter?

A string inverter is a single, central inverter that is connected to a group of solar panels (called a string). Everything that the DC electricity from that string does is routed to one box, typically located close to your meter room or ground floor, and the electricity is converted to usable AC electricity.

Most residential and commercial setups in India are set up like this. It is easy and well known to installers, simple to service, and easy to understand.

What Is a Micro Inverter? 

The opposite of a micro inverter is a string inverter. The small inverter is mounted directly behind each panel on a roof rather than a large inverter for the entire array. The conversion of DC to AC takes place directly at the panel and the AC output from each module adds up to the AC output from the switchboard.

This means that each panel functions on its own. Unlike a string inverter setup, if one panel is underperforming because of shade, dust or fault, it will not affect the performance of the other panels.

Key Differences Between Micro and String Inverters 

The two differ most on their shading tolerance. String inverter: Panels are connected in series and the entire string's output matches the output of the weakest panel. One panel on a water tank, tree branch or nearby building can cause the entire string to drop. In the case of micro inverters, each panel operates separately, and shading one panel has minimal impact on the others.

Monitoring also differs. Micro inverters usually come with an app that will provide panel-level monitoring, providing real-time data on the output of each module. The combined output of a string inverter, or the system level, is typically shown and is more coarse grained but adequate for most installations.

Efficiency in ideal conditions slightly favours string inverters. If the roof is unshaded and single oriented, a string inverter is an efficient converter of DC to AC and there is no significant drop to compensate for.

The suitability of the roof is also important. A string inverter setup becomes more complex if your roof has multiple orientations, as sections with different orientations have different power production and a poor performing section drags the entire string down. This is something that is taken care of naturally by Micro inverters as each panel functions separately.

Cost Comparison in India

This is generally the most important criteria for most Indian buyers and it is substantial.

The typical price range of string inverters for residential installations (3-10 kW) is approximately ₹22,000 to ₹40,000 per unit (excluding installation). Growatt, UTL and Polycab are popular brands, and have good networks of service providers.

Micro-inverters are sold by the unit (panel) and their cost is usually between ₹5,000 and ₹12,000 per unit depending on the brand and the wattage of the panel. The cost of this starts to add up rapidly for a 6-8 panel system with a 3 kW inverter, and can easily increase the total installation cost by 30-50% compared to a similar string inverter installation. While Enphase is the most popular micro inverter brand in India, its availability and the local servicing are still lagging behind popular string inverter brands.

Side-by-Side Comparison

Which One is Best for Your Roof?

A string inverter is more cost-effective for flat roofs, where there are no obstructions between the panels and no shadowing. It is less expensive, has a proven service network in India, and there is not much to be gained from optimising the performance of the panel.

Micro inverters are typically a good value if your roof is partially shaded by adjacent buildings, water tanks, chimneys, or trees, or if you have multiple sections of your roof oriented in different directions. The energy benefit of shading isolation can be anywhere from 5% to 25% depending on the level of shading, and the benefit accumulates over the system's lifetime.

In the case of the simplest Indian residential rooftops, a string inverter is the default and logical solution. Micro inverters are worth the extra initial price for complex roofs, partially shaded apartment terraces, or high-end installations that require detailed information per panel.

Maintenance and Long-Term Considerations

String inverters are easier to maintain, as they can be serviced from the ground without the need to go up on the roof. They generally come with a 5-10 year warranty in India, but the unit may require replacement after 25 years of a panel's life.

With the micro inverters installed throughout the roof, it's a case of having to physically go on the roof to find the fault. This involves labour costs and is weather dependent, but there is a very low failure rate historically and many owners will never require a replacement during the life of the system.

Will the choice of inverter impact the subsidy eligibility?

String inverters and micro inverters can both be eligible for net metering and the central PM Surya Ghar Muft Bijli Yojana subsidy, as long as the entire system (panels and inverter) complies with the technical and ALMM standards established by your DISCOM. The subsidy is based on system capacity and equipment certification, not the architecture of the inverter.

Frequently Asked Questions

Which is cheaper, micro or string inverters? 
String inverters, which are typically 30-50% cheaper than a string of micro inverters.

Are there more electricity produced with micro inverters? 
Yes, on shaded roofs and on roofs with multiple orientations, often 5–25%. This difference is negligible on unshaded roofs.

Can I use micro inverter + string inverter in a system? 
Although technically feasible, it is not common in Indian households as it makes the design, monitoring and warranty process difficult.

Which one would you prefer for your 3kW small home system? 
If there is any meaningful shading on the roof, then micro inverters may be worth it, even if the roof is small, but otherwise, a string inverter will likely be enough.

Do micro inverters need more maintenance? 
Repairs must be done on the roof, as opposed to string inverters that are serviced from the ground, but not more often.

For commercial roofs, which is better? 
While micro inverters are useful for small commercial installations, string inverters are the norm for large commercial installations and are often used in conjunction with power optimisers, as micro inverters become costly for installations of hundreds of panels.

There is no single best option between micro Inverters and string inverters, it depends on the type of roof you have. A clean, unshaded roof will likely not require the added expense of micro inverters, whereas a roof that is shaded, or has multiple orientations or is required for detailed monitoring will likely pay for itself over time. Before you make a choice, have your installer properly assess your roof, as the cost of a replacement inverter is much higher than that of the correct choice.