Replacing your solar inverter in Perth: what's involved and what it costs

Replacing a string inverter in Perth is usually a half-day job for a licensed electrician, and it typically lands somewhere between $1,500 and $3,500 installed depending on the size of your system. A straight like-for-like swap needs no new network approval. The appointment is also the cheapest chance you'll get to add a battery, because the electrician already has your system open.

If your panels have stopped generating and the inverter screen is blank or showing a red light, the inverter is the most likely culprit. Panels usually outlive the inverter by a decade or more, so a mid-life system that goes dark is nearly always an inverter problem, not a panel one.

Perth has a large cohort of systems installed between 2009 and 2015, when the federal solar bonus scheme drove rapid uptake. Those early string inverters, often Fronius, SMA, ABB or Power One, are now 10 to 16 years old. Replacing them has become routine. Here's what to expect.

How do you know the inverter has failed?

Age is the usual driver. Inverters tend to fail before the panels do, so on a system that's a decade or more old, the inverter is the first thing to suspect when output drops.

A few signs point to a dying or dead inverter:

• A blank screen or a red fault light, with generation stopped entirely. This is the clearest sign.
• Persistent fault codes, especially as the hardware ages. Common ones include grid frequency out of range (which can be a false positive as components drift), a DC isolation fault (insulation resistance dropping), a temperature shutdown (thermal management struggling), and fan failure. The cooling fan is often the first part to wear out.
• A sudden, no-warning stop. Plenty of inverters die abruptly rather than fading. One day the system is fine, the next it's off.

Perth's summers make it harder. High enclosure heat accelerates component ageing, so units here tend to reach the end of their working life sooner than the same model in a cooler climate. For a deeper look at that timeline, see our guide on how long a solar inverter lasts in Perth.

One thing worth checking before you pay for a replacement: some home and contents policies cover inverter failure, particularly when the cause was a power surge. It's worth reading your policy before you assume the cost is all yours.

What does replacing a string inverter actually involve?

For a qualified Perth electrician, a straight swap is a well-worn job. It runs in five steps:

1. Disconnect and isolate. The electrician turns off the AC isolator at the switchboard and the DC isolator at the inverter. Here's the catch that makes this specialist work: the DC wiring from the panels can't be fully de-energised in daylight, because the panels keep generating as long as the sun is on them. It's done with the right protective equipment and safe procedures.
2. Remove the old unit. The failed inverter comes off the wall. Anything over about 15 kg needs two people.
3. Mount and wire the new unit. The replacement goes up, usually in the same spot, and the DC and AC wiring is reconnected. Monitoring is set up either through the existing generation meter or over WiFi.
4. Recommission. The system is powered back on and checked so it's generating and reporting correctly.
5. Certificate of compliance. The electrician issues an updated electrical certificate of compliance for the work.

The hands-on part is quick. For a standard home system, expect a few hours of labour.

Do you need a new Western Power approval?

For a like-for-like replacement, no. Swapping in an inverter of the same or smaller capacity does not need a fresh network connection application. A like-for-like warranty replacement is specifically exempt.

Where it changes is capacity. Under the WA connection rules that took effect in May 2026, a standard residential connection allows up to 30 kVA of inverter capacity in total, with single-phase inverters capped at 10 kVA. If your replacement lifts your capacity, that's treated as an upgrade rather than a swap, and it may need a new application. Your installer will confirm which side of the line your job sits on. We cover the process in more detail in our Western Power connection approval guide and the new WA inverter rules from May 2026.

What does an inverter replacement cost in Perth?

As a rule of thumb, a replacement string inverter runs from about $1,500 to $3,500 installed, scaling with system size. Small single-phase systems sit at the lower end; larger three-phase systems sit at the top. Those figures include labour and exclude GST, and they move with your installer and where you are in the metro area.

The reliable way to know your number is a written quote. Prices shift by brand and by how accessible your switchboard and mounting location are, so a fixed table can mislead more than it helps. Get the quote in writing, and ask what warranty comes with the replacement unit.

Can you switch inverter brands, or should you stay with the same one?

You can switch. Panels and inverters talk to each other only through standard DC voltage and current, so any compatible string inverter works with your existing panels. You are not locked into replacing a Fronius with a Fronius.

The main trade-off with switching is monitoring. If you move from, say, an SMA Sunny Boy to a Fronius Primo, the monitoring app changes and your old generation history doesn't come across. That's a minor annoyance, not a technical barrier.

Staying with the same brand has its own small upside. Some installers find the wiring simpler when the form factor matches, and a familiar unit can be quicker to fit. Fronius and Sungrow both have solid Australian service networks, which matters if you ever need warranty support. If you're weighing the two, our Fronius vs Sungrow comparison goes through it in detail.

Should you add a battery while the system is open?

This is the part most people don't think about until the electrician has left, and by then the moment has passed. An inverter replacement is the ideal time to add a battery, for one practical reason: the AC and DC systems are already disconnected and open. Doing both in one visit saves a return trip and cuts the combined labour cost.

You've got a few routes:

• Upgrade to a hybrid inverter. Instead of another string inverter, fit a hybrid unit with built-in battery management. It costs more than a plain string replacement but less than a string inverter plus a separate AC-coupled retrofit later. Our hybrid inverter guide walks through the trade-offs.
• Keep a string inverter and add an AC-coupled battery. A Powerwall-style AC-coupled battery works with any existing PV system, whatever the inverter brand. This keeps your options open if you're not ready to commit to a battery today.

If a battery isn't on the cards right now, our guide on adding a battery to an existing solar system in Perth covers doing it as a standalone job later.

What warranty should the replacement inverter carry?

Warranties differ by brand, so check the specific unit rather than assuming a category number:

• Fronius comes with a 5-year standard warranty that extends to 10 years for free once you register the unit online. On recent stock, that 10-year cover is the default from commissioning.
• Sungrow carries a 10-year standard warranty across its residential range in Australia.

A 10-year warranty is worth seeking on a replacement, since you don't want to be back here again in five years. Ask your installer to confirm the term in writing before the job goes ahead.

Under the New Energy Tech Consumer Code, a compliant Approved Seller provides a minimum whole-of-system warranty, and Australian Consumer Law guarantees apply on top of any manufacturer term. If your original inverter failed under warranty and the installer has since closed down, the claim passes to the manufacturer's Australian distributor rather than disappearing.

The short version

Replacing a string inverter in Perth is a standard job, a few hours of labour, and typically $1,500 to $3,500 installed depending on system size. A like-for-like swap needs no new network approval; a capacity increase counts as an upgrade and may. The replacement visit is the best-value moment to add a battery or move to a hybrid inverter, because the system is already open. Get the warranty term in writing, and aim for 10 years.