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

Perth has a large cohort of solar systems installed between 2009 and 2015, when the Federal government's solar bonus scheme drove rapid adoption. These systems' string inverters — typically Fronius, SMA, ABB, or Power One units — are now 10–16 years old and entering end-of-life territory. Inverter replacement is becoming routine maintenance in Perth. Here's what to expect.

What triggers an inverter replacement?

Age-related failure is the most common driver. String inverters are typically warranted for 5–10 years and have a practical service life of 10–15 years in Perth's climate. The Perth climate is particularly tough on inverters — enclosure temperatures regularly reach 50–60°C in summer, accelerating component degradation.

Fault codes: Inverters approaching end of life often throw persistent fault codes:

• Grid frequency out of range (can be false positives as hardware degrades)
• DC isolation fault (insulation resistance degrading)
• Temperature-related shutdown (thermal management failing)
• Fan failure (cooling fan worn out — often the first failure mode)

Sudden failure: Many inverters fail suddenly rather than with advance warning. If generation stops entirely and the inverter display is blank or showing a red indicator, the inverter has likely failed.

Insurance claim: Some home and contents or home insurance policies cover inverter replacement after sudden failure. Check your policy — if the failure was caused by a power surge, it's more likely to be covered.

What inverter replacement involves

A string inverter replacement is straightforward for a qualified Perth electrician:

1. Disconnect and isolate: Turn off the AC isolator (at the switchboard) and the DC isolator (at the inverter). The DC isolator disconnects the panels — however, the DC wiring from panels to the inverter CANNOT be fully de-energised during daylight hours, as panels continue generating as long as they're illuminated. All work is done with appropriate PPE and safe working procedures.

2. Remove old inverter: Unmount the failed unit. If it's over 15kg, this requires two people.

3. Install and wire new inverter: Mount the replacement unit in the same location (or a new location if the wall surface has deteriorated). Connect DC wiring from panels, AC wiring to switchboard. The inverter communicates with the existing generation meter on the roof (if present) or is configured for monitoring via WiFi.

4. Recommission: Power on and verify the system is generating and reporting correctly.

5. Certificate of compliance: The electrician issues an updated electrical certificate of compliance for the installation.

Does inverter replacement require a new Western Power NCN? Generally no — replacing a like-for-like inverter (same or smaller export capacity) does not require a new NCN application. If you're increasing the inverter capacity (e.g., upgrading from a 5kW to a 10kW inverter), a new NCN may be required. Confirm with your installer.

Inverter replacement cost in Perth (2026)

| System size | Replacement inverter brand | Installed cost range | |---|---|---| | Up to 5kW | Fronius Primo, Goodwe GW5000, Sungrow SG5.0RS | $1,000–$1,600 | | 6–8kW | Fronius Symo (3-phase) or single-phase options | $1,400–$2,200 | | 10kW | Fronius Symo 10.0-3-M, Sungrow SG10RT | $1,800–$2,800 | | 13.3kW (3-phase residential) | Fronius Symo 15.0 or Sungrow equivalent | $2,400–$3,500 |

Prices are installed (labour included) and exclude GST. Prices vary by installer and location within Perth.

Labour for the replacement itself is typically 2–4 hours for a standard residential system.

Should you stay with the same brand?

You don't have to replace a Fronius with a Fronius, or an SMA with an SMA. The panels and inverter communicate only through standard DC voltage and current — any compatible string inverter can be installed with existing panels.

Brand switching consideration: If you have an SMA Sunny Boy and want to switch to Fronius Primo (or vice versa), the monitoring platform changes — your historical data in the old platform won't transfer. This is a minor inconvenience.

Staying with the brand: Some installers recommend the same brand for familiarity, and the technical wiring may be simpler if the form factor matches. Fronius and Sungrow both have strong Perth service networks.

The battery co-installation opportunity

Inverter replacement is an ideal time to consider adding a battery. Why:

• Electrical access is already open: The electrician has already disconnected the AC and DC systems. Adding a battery while the system is open for inverter replacement saves a return trip and reduces the combined labour cost.
• Hybrid inverter upgrade: Instead of replacing with another string inverter, you can upgrade to a hybrid inverter (e.g., Sungrow SH10RT, Goodwe GW10K-ET) that has built-in battery management. This costs more than a string inverter replacement but less than a separate battery + retrofit AC-coupled setup.
• AC-coupled battery: Alternatively, keep a new string inverter and add an AC-coupled battery (Powerwall-style) — these work with any existing PV system regardless of inverter brand.

Warranty considerations on replacement

When replacing an inverter, confirm the warranty on the replacement unit:

• 5-year warranty: Standard on entry-level inverters; acceptable but not ideal for a second replacement
• 10-year warranty: The better choice for longevity — Fronius offers 10-year extended warranty options; Sungrow units come with a 10-year standard warranty in some configurations

If your old inverter failed under its original warranty and the installer has gone out of business, the warranty claim passes to the manufacturer directly — contact the manufacturer's Australian distributor.

Perth string inverter replacement is a standard 2–4 hour job, costing $1,000–$3,500 installed depending on system size. No new NCN is required for like-for-like replacement. The replacement appointment is a practical opportunity to co-install a battery or upgrade to a hybrid inverter with built-in battery capability. Confirm warranty terms on the replacement unit — 10 years is worth seeking.