Solar panels produce direct current, but homes and the grid use alternating current. The inverter converts one into the other, and it is one of the most important components in a solar system. The type of inverter you choose affects performance, monitoring, safety features and long-term maintenance.
What an Inverter Does
Besides converting electricity, an inverter manages the system's output, tracks the maximum power point of the panels and shuts down when the grid goes down, as required by safety standards. Most also provide data on production and may communicate with batteries and smart meters.
String Inverters
A string inverter connects a series of panels wired together and converts their combined output in one central unit, usually mounted near the electrical panel. They have been used for many years and typically cost less per watt. Because panels in a string share a current, shading or a problem on one panel can reduce the output of the whole string. They work best on simple, unshaded roofs with panels facing the same direction. Inverter replacement is often needed once or twice over the life of the panels, since many carry shorter warranties than the panels.
Microinverters
A microinverter is attached to each panel and converts power right at the source. Each panel operates independently, so shading or soiling on one has less effect on the rest. Microinverters also allow panel-level monitoring and often work well on roofs with multiple orientations. Their drawbacks include higher upfront cost and having many electronic components on the roof, which can be harder to access for service. Many carry long warranties, commonly up to 25 years.
Power Optimizers
Power optimizers are mounted on each panel and condition the DC power before sending it to a central inverter. They offer panel-level monitoring and mitigate shading losses, with the central inverter handling the final conversion. Costs fall between string and microinverter systems. They are often paired with certain inverter brands, so compatibility matters.
Hybrid and Battery-Ready Inverters
If you plan to add storage, a hybrid inverter that manages both solar and a battery can simplify the system. Other designs support batteries through separate inverters. Mention any future plans during the quoting process.
Questions to Ask Your Installer
- Why is this inverter type recommended for my roof and shading conditions?
- What are the equipment and workmanship warranties, and who handles claims?
- Does the system include panel-level monitoring and rapid shutdown, as required by code?
- How would the system perform during a grid outage, and can it support a battery later?
- What is the expected lifespan and replacement cost of the inverter?
Choosing the Right Option
For a simple, unshaded roof and a tight budget, a string inverter can be a good choice. For complex roofs, shading or a desire for panel-level data, microinverters or optimizers may be worthwhile. Quality and installer expertise matter as much as the technology. Get written quotes that identify the exact equipment and warranty terms so that you can compare systems on equal footing.