Commercial solar inverters explained

Solar panels produce direct current, but the equipment in a commercial building, along with the grid, runs on alternating current at 230 or 400 volts. The inverter sits between the two, converting DC into grid-compatible AC many thousands of times a second. Without it, the electricity your roof generates cannot power a single socket.

A modern commercial inverter does more than convert. It tracks the maximum power point of each panel string so output stays high as sunlight changes, records generation data for monitoring, and disconnects safely if it detects a grid fault or a problem on your side of the meter.

String inverters connect a series (a string) of panels to a single unit, with several strings feeding several inverters across a larger roof. They are cost-effective, easy to service one at a time, and suit most commercial rooftops. Central inverters handle very large arrays through one big unit and tend to appear on ground-mounted or industrial-scale sites.

Microinverters take a different approach, fitting one small inverter to each panel so shading or a fault on one module does not drag down the rest. They cost more per watt but can make sense on roofs with dormers, chimneys or awkward shading. The right choice depends on roof shape, shading and how you want to monitor performance.

Panels are often warranted for 25 years or more, but inverters work harder and typically carry a 5 to 12 year warranty. Over a 20-year system life you should budget for at least one inverter replacement. Good installers plan for this from the start, choosing units with accessible mounting and clear monitoring.

Under a funded route such as a PPA, inverter replacement and maintenance usually sit with the funding partner rather than your business, because they own and operate the system until the nominal £1 buyout. Confirm exactly what the agreement covers so there are no surprises when a unit reaches the end of its life.