How often should you replace a solar inverter?
Updated July 2026
A string solar inverter lasts 10–15 years, which is only about half the 25–30 year life of the panels it feeds, so plan on replacing the inverter once over the system's lifetime. Microinverters, one mounted under each panel, are built to last 20–25 years and roughly match the panel life. Either way, the inverter is the component most likely to fail first, because it runs hot power electronics all day. When it dies, production drops to zero until it is swapped, at $1,500–3,000 for a string unit.
What changes the interval
| Your situation | Interval | Why |
|---|---|---|
| String inverter (one central unit) | Every 10–15 years | The single most likely component to fail |
| Microinverters (one per panel) | Every 20–25 years | Match panel life; a failure is isolated to one panel |
| Power optimizers plus a string inverter | Inverter at 10–15 years | Optimizers outlast the central inverter |
| Hybrid or battery inverter | Every 10–15 years | More electronics, similar lifespan |
| Installed in a hot attic or garage | Nearer the low end | Heat is the top killer of inverter electronics |
| Fault codes or zero production | Diagnose and replace now | Every dark day is lost generation and savings |
The cost of skipping it
What ignoring it costs: a dead inverter is not a slow decline, it is an off switch for the whole array. Every sunny day it sits faulted is kilowatt-hours you paid for and are not banking, which quietly stretches the payback period on a five-figure system. Replacement runs $1,500–3,000 for a string unit installed. The standard 10–12 year warranty may cover the part, but often not the $300–800 of labor, and a failure at year 11 with no monitoring can go unnoticed for weeks. See how long a solar inverter lasts for the full lifespan picture.
How to do it (Solar technician · $1,500–3,000 replaced)
- Check the monitoring app weekly; a healthy inverter reports production every sunny day.
- Watch for fault lights or error codes on the unit itself, not just in the app.
- Note the in-service date and warranty term (usually 10–12 years) so a year-11 failure is no surprise.
- Keep the inverter shaded and ventilated, and clear leaves or debris from its vents.
- When it fails, get quotes for a like-for-like swap and confirm exactly what the warranty covers.
- At replacement, weigh microinverters or a longer-warranty model against another string unit.
Knowing the interval is the easy half. OnOtto reminds you at the right interval, and it won't let you snooze it into next year. Tasks persist until they're done, and completing inverter replacements schedules the next one automatically.
Put this on autopilot, free for 30 daysFrequently asked questions
Why does the inverter fail before the panels do?
Because it does the hard electrical work. Panels are passive glass and silicon with no moving parts, so they degrade slowly, losing roughly half a percent of output a year. The inverter, by contrast, switches DC into AC thousands of times a second all day long, and its capacitors and semiconductors run hot and wear out. Heat is the accelerant, which is why an inverter baking in an unshaded attic or on a sun-blasted wall tends to land at the short end of the 10–15 year range.
Should I switch to microinverters when mine fails?
It is worth pricing. Microinverters last 20–25 years, so you likely never replace them again, and a single failure only takes one panel offline instead of the whole array. They also handle partial shade better. The tradeoffs: more units mounted on the roof means more potential fault points up high, and the upfront cost is higher. If your string inverter has already failed once and your roof sees shade, microinverters or optimizers often make sense on the second round.
Does the warranty cover the replacement cost?
Read the terms, because part and labor are usually separate. Most string inverters carry a 10–12 year parts warranty, sometimes extendable to 20–25 years for a fee. That covers the hardware, but the $300–800 of labor to diagnose, uninstall, and mount the replacement is frequently on you unless you bought a labor plan. If the original installer is out of business, you may also need to source the part yourself. Knowing your term and end date is half the battle.
How do I tell a failed inverter from a run of cloudy days?
Cloudy days cut production; a failed inverter zeroes it. Pull up the monitoring app and look at a clearly sunny day: if the panels are lit and the app shows no output, or shows a fault code, the inverter, not the weather, is the problem. On the unit itself, a red fault light or a blank display is the tell. If a single panel or two drop out while the rest produce, that points to one microinverter or optimizer rather than the whole inverter.