Solar inverter repair and replacement
The inverter is the part that fails. Panels are glass and silicon with no moving parts and routinely outlast their warranties; the inverter is working electronics sitting in sustained inland heat, and it is the component that ends most systems' production.
Which kind do you have?
Three architectures dominate residential solar, and the difference matters enormously to your repair bill.
String inverter
One box, usually mounted on the garage wall or beside the main panel, converting the output of the whole array. Simple and inexpensive, with one significant weakness: when it fails, the entire system stops. Every homeowner who says "my solar just quit all at once" has a string inverter. Typical service life runs roughly ten to fifteen years, and heat shortens it.
Microinverters
A small inverter under each panel, Enphase being the most common brand. One failure takes out one panel's worth of production, which is why the failure mode here is gradual: output drifts down over years rather than stopping dead. You may not notice without monitoring.
String inverter with power optimizers
Typically SolarEdge. Optimizers on each panel feed a central inverter. Either component can fail, with correspondingly different symptoms — an optimizer failure looks like the microinverter case, a central unit failure looks like the string case.
Why inland California is harder on inverters
Electronics degrade with heat, and the inland valleys deliver a great deal of it. A garage-mounted inverter through a run of hundred-degree days is operating near the top of its thermal envelope for months at a stretch. Add the dust that settles on cooling fins across the inland valleys, and units here can reach the end of their useful life noticeably earlier than the same model in a coastal climate.
None of this makes solar a bad investment locally — the same sun that cooks the inverter is why inland California arrays produce so well. It does mean you should expect at least one inverter replacement over the life of a system, and budget for it rather than being blindsided.
Reading the signs
- A blank screen or no lights. No power reaching the unit, or the unit has failed entirely. Check whether the AC disconnect or breaker has tripped before assuming the worst.
- A red fault light or error code. Note the exact code. It is the single most useful thing you can tell a technician on the phone and it often narrows the diagnosis before anyone drives out.
- Ground fault or arc fault indication. A safety shutdown, frequently caused by damaged wiring or moisture intrusion rather than the inverter itself. This one is genuinely worth treating as urgent.
- Production far below normal. A partial failure — one string down, or several microinverters out. It will not announce itself, so it usually surfaces via the utility bill.
- Frequent restarts. The system produces, then drops out, then recovers. Often overheating or a grid voltage issue.
Do not open the inverter. A solar array produces dangerous DC voltage whenever the sun is on it, and it cannot be switched off at the panel. There is no homeowner-serviceable part inside the enclosure. Reading the display and checking the breaker is the full extent of safe DIY here.
Repair or replace
Modern inverters are largely sealed assemblies, so component-level repair is uncommon in residential work. The real decision is usually about the replacement unit.
If the failed unit is still inside its manufacturer warranty — typically ten to twelve years for a string inverter, longer for many microinverters — the replacement hardware may cost you nothing and you pay for labor and the warranty claim. This is why identifying the manufacturer and install date early is worth real money.
If it is out of warranty, you are buying a new unit. Ask about a like-for-like replacement versus an upgrade; a newer inverter may offer better monitoring or battery readiness, but it also has to be compatible with your existing array and permitted correctly.
What it costs
Planning ranges for California. Get a written quote before authorizing anything.
- Diagnostic visit: $150 to $400, frequently credited toward the repair.
- String inverter replacement, out of warranty: roughly $1,500 to $3,500 installed, depending on size and brand.
- String inverter replacement, under warranty: labor and claim handling only, commonly $500 to $1,200.
- Microinverter replacement: $250 to $500 per unit installed, since panels must be lifted to reach them.
- Power optimizer replacement: $200 to $400 per unit installed.
Replacing a string inverter usually requires a permit and an electrical inspection. A contractor who skips that step is not saving you money, they are creating a problem for the next time you sell the house.