Upgrading Your Old Solar System Perth 2026: What the Right Move Is for Your Install Year

Perth has one of the highest rates of rooftop solar adoption anywhere in the world, and a very large portion of those systems were installed before 2018. If yours is one of them, there is a good chance it was sized for a different era, installed to a different set of rules, and running on equipment that is now at or approaching the end of its useful life. Upgrading an old solar system is a common Perth project, and getting the sequence right matters.

The right upgrade path depends on when your system was installed. The answer is different for a 2012 system, a 2016 system, and a 2020 system. Understanding why matters before you start getting quotes or making decisions.

Perth’s Three Solar Eras

The history of residential solar in Perth roughly splits into three periods, each with different system sizes, equipment standards, and compliance requirements. Knowing which era your system belongs to is the starting point for any upgrade conversation.

Pre-2015: Small Systems, Ageing Equipment, Full Replacement

The early wave of Perth solar installations, roughly 2010 to 2014, happened when solar panels cost substantially more per watt than they do today. At that price point, most households installed small systems: 1.5kW, 2kW, or 3kW was typical. The thinking at the time was that a small system would cover a portion of daytime usage and pay for itself reasonably quickly at the electricity prices of the era.

Those systems are now 11 to 15 years old. Panels from that period have been degrading for well over a decade. Even well-performing panels lose output year on year. The panels available in 2010 to 2014 were not the high-efficiency, low-degradation products available today. Inverters from that era are at or well past their typical 10 to 15 year lifespan. Many of those older string inverters had no monitoring capability. There was no app to check generation, no alerts when output dropped, and no way to see whether the system was performing to expectation.

For systems installed before 2015, the answer is almost always full replacement. The equipment is aged, the system is undersized for today’s household energy needs, and compliance with current wiring rules and grid connection requirements means the old installation cannot simply be patched or extended. A full replacement starts fresh, with modern panels, a right-sized system, a hybrid inverter, battery storage, and real monitoring.

• Typical system size: 1.5kW to 3kW.
• Inverter age: 11 to 15+ years — at or past end of useful life.
• Monitoring: Little to none on older string inverters.
• Panel output: Significantly degraded after 11-15 years of Perth heat and UV exposure.
• Right move: Full system replacement with solar, battery, and hybrid inverter.

2015 to 2018: Larger Systems, But Compliance Requirements Have Changed

From around 2015 onward, solar panel costs had come down enough that households started installing larger systems: 5kW, 6kW, and 6.6kW became much more common. The investment made more sense at lower prices, and the systems installed in this period were genuinely useful, covering a meaningful portion of household consumption.

Those systems are now 8 to 11 years old. The inverters are reaching the upper end of their typical lifespan. Panels are still generating, but have lost output through years of degradation. Critically, the electrical wiring standards that governed solar installations changed significantly with the AS/NZS 3000:2018 Wiring Rules, which became mandatory from January 2019.

In practice, this means a system installed between 2015 and 2018 was installed to the wiring rules current at the time, rules that have since been superseded. When you modify an existing solar installation, the work must comply with the current standards. Adding a battery, replacing an inverter, or adding panels to a 2015-2018 system does not simply mean connecting new equipment to an old installation. It triggers a compliance assessment against current wiring rules. In many cases, the cost and complexity of bringing the existing wiring up to standard makes a full system replacement the more practical and cost-effective path.

Add to this the grid connection requirements introduced from May 2026, which require any new or upgraded system to support remote disconnection capability or accept a 1.5kW export limit, and the case for a full replacement over a partial upgrade becomes clear. A new installation is designed to meet all current requirements from the ground up. A partial upgrade to an older system often needs significant additional work to reach the same outcome.

• Typical system size: 5kW to 6.6kW.
• Inverter age: 8 to 11 years — approaching or at end of typical useful life.
• Wiring rules: Installed under pre-2019 standards — current standards apply to any modification.
• Grid connection: Post-May 2026 upgrade requirements apply to any modified system.
• Right move: Full system replacement in most cases — more cost-effective than patching to compliance.

Post-2018: Battery Addition or Inverter Upgrade

Systems installed from 2019 onward were built to current wiring rules, and depending on the inverter choice, may already be battery-ready. For these systems, the upgrade conversation is different, and the options are genuinely flexible.

If You Have a Hybrid Inverter

A hybrid inverter is designed to connect directly to a battery. If your 2019 or later system has a hybrid inverter, such as a Fronius GEN24 PLUS, SigEnergy, Sungrow hybrid, or similar, adding a battery is straightforward. The inverter already has the battery management capability built in. The addition is a battery and the cabling to connect it.

This is one of the highest-return upgrades available to Perth households right now. Your panels are already generating. Every kilowatt-hour that currently goes to the grid at the low DEBS off-peak rate of 2 cents could instead be stored and used in the evening, when grid electricity costs more than 30 cents. The CHBP federal battery rebate and WA state battery rebate both apply to a battery addition on an existing solar system, making the investment more accessible than ever.

If You Have a Standard String Inverter

A standard string inverter cannot connect to a battery directly. For households with a post-2018 system and a string inverter, the options are to replace the inverter with a hybrid model (which then enables battery addition), or to install an AC-coupled battery system that connects separately from the inverter. Your energy consultant will assess which path suits your system configuration and goals.

• Typical system size: 6.6kW to 10kW and above.
• Inverter age: 5 to 7 years — well within useful life.
• Wiring rules: Installed under current or near-current standards.
• Right move: Battery addition (if hybrid inverter), or inverter upgrade to hybrid then battery.

The May 2026 Grid Connection Rules

From 1 May 2026, any new or upgraded solar or battery system connected to the Western Power network must either support remote disconnection and reconnection by Synergy (the CSIP-AUS standard), or accept a fixed export limit of 1.5kW.

Systems installed before 1 May 2026 are not affected. They continue operating under the rules that applied when they were installed. But any upgrade after that date, whether a battery addition, inverter replacement, or full system installation, must meet the new requirements.

This means equipment specified for any post-May 2026 upgrade must be CSIP-AUS compliant. It also means systems capped to the 1.5kW export limit may not be eligible for DEBS export payments, which is a significant consideration in system design. Positive Energy Solutions specifies CSIP-AUS compliant equipment as standard, so your new or upgraded system is designed for DEBS eligibility from day one.

For a full explanation of the May 2026 changes and what they mean for Perth households, see our guide: WA Solar Battery Rules 2026.

What a Full System Replacement Gives You

For households whose system falls in the pre-2015 or 2015-2018 era, a full replacement is not just the compliant path. It is also the best energy outcome. A modern solar and battery system is a fundamentally different proposition from what was available a decade ago.

• Right-sized for today: a system designed around your actual current consumption, including any heat pump, EV charger, and other modern loads, rather than a 2012-era household. Panels today are 460W versus the 200-250W panels common in the early wave, so the same roof space produces substantially more energy.
• SunPower P-series panels: Positive Energy Solutions installs SunPower P-series panels exclusively: TOPCon shingled-cell, glass-glass construction, a 30-year warranty covering product, performance, and labour, and IEC 61701 maximum severity salt mist certification. A step change from budget or mid-tier panels installed in the early solar wave.
• Hybrid inverter: battery-ready from installation day. Your system is designed to accept battery storage now or when you are ready, without needing further inverter work.
• Battery storage: covered by the CHBP federal rebate and WA state battery rebate. Store self-generated solar energy for use in the evening, rather than exporting at 2 cents per kilowatt-hour.
• Real monitoring: modern inverter systems provide generation, consumption, and battery data through an app. Every installer Positive Energy Solutions works with also registers your system with Omnidian, a dedicated after-sales service company that monitors performance independently, investigates any issues, and coordinates warranty or service action on your behalf.
• Current compliance: CSIP-AUS compliant, meeting current wiring rules and grid connection requirements from day one.

Rebates Available on a Replacement or Upgrade

Whether you are doing a full system replacement or adding a battery to an existing post-2018 system, multiple rebates are available to reduce the upfront cost.

• Small-scale Technology Certificates (STCs): The federal solar panel rebate applies to new panels as part of a full replacement. Applied as an automatic discount at point of sale — no paperwork required from you.
• Cheaper Home Batteries Program (CHBP): The federal battery rebate applies to battery installations, including batteries added to existing solar systems. Positive Energy Solutions is an approved CHBP supplier and manages the application.
• WA State Battery Rebate: A separate WA government battery rebate that can be stacked with the CHBP for eligible households. Your energy consultant will confirm eligibility.
• Plenti Interest-Free Loan: For eligible households, the WA state government no-interest loan through Plenti can cover upfront costs. Positive Energy Solutions initiates the application as part of your project.

For a full breakdown of what is available, see our hub post: Solar Rebates and Incentives WA 2026.

Related guides

• Before Your Solar Is Installed in Perth: What to Expect From Sign-Off to Installation Day
• How Much Solar Battery Storage Do I Need? Perth 2026 Guide
• How to Choose a Solar Installer in Perth: What to Look For (and What to Watch Out For)
• How to Read a Solar Quote in Perth: What Should Be There, What to Question, and Why Two Quotes Are Never the Same

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Frequently Asked Questions

How do I know when my system was installed?

The installation date is typically on the electrical certificate of compliance issued at the time of installation, or on a sticker on the inverter. Your Synergy account may also show the date your solar connection was established. If you are not sure, Positive Energy Solutions can assess your system during a site visit, and give you a clear picture of what you have and what condition it is in.

Will I lose my old feed-in tariff if I replace my system?

If your system is on the Renewable Energy Buyback Scheme (REBS), the tariff that applied to early solar installations, replacing your system will move you to the current Distributed Energy Buyback Scheme (DEBS). REBS offered a flat rate that was more generous in nominal terms. But given the small size of those early systems and the much higher electricity costs today, the value of moving to a larger, battery-equipped system that maximises self-consumption typically outweighs the loss of the REBS premium. Your energy consultant will model the numbers for your specific situation before you commit to anything.

Can I claim the battery rebate even though I already have solar?

Yes. The CHBP and WA state battery rebate both apply to battery installations on existing solar systems. You do not need to install new panels at the same time. If you have a post-2018 system with a hybrid inverter and are considering adding a battery, you can access both rebates. Positive Energy Solutions manages the applications as an approved supplier.

My old inverter has died — what should I do?

A failed inverter on a pre-2015 or 2015-2018 system is typically the point where a full system replacement makes the most economic sense. Replacing only the inverter on an older system needs a compliance assessment against current wiring rules, the new inverter must be CSIP-AUS compliant, and you still end up with ageing panels on an undersized system. In most cases, the cost difference between an inverter-only swap and a full system replacement with battery, after rebates, is much smaller than it first appears. Speak to a Positive Energy Solutions energy consultant before committing to an inverter-only repair on an older system.

Do I need to notify Synergy when I replace my system?

Yes. Any modification to your solar connection requires notification to Synergy and a new Western Power grid connection application. Positive Energy Solutions manages both the Synergy notification and the Western Power application as part of every installation — you do not need to deal with either directly.

Can I add more solar panels to my existing system?

Adding panels to an existing system counts as an upgrade, and triggers compliance with current wiring rules and grid connection requirements. For pre-2018 systems, this typically makes a full replacement more practical. For post-2018 systems, it depends on your current inverter capacity and roof space. Your energy consultant will assess your system and advise on the best approach for your specific situation.

What happens to my old panels and inverter?

Old equipment is removed as part of the replacement installation. Solar panels can be taken to panel recycling facilities — the federal government has established a national recycling pilot program to handle end-of-life panels. Your installation team will advise on disposal options at the time of your project.

Ready to Find Out Where Your System Stands?

Whether your system is 15 years old or 5, Positive Energy Solutions can assess what you have, explain your options clearly, and design the right upgrade for your household. For older systems, that usually means a full replacement sized correctly for today — with better panels, battery storage, real monitoring, and every available rebate applied.

About the Author

Jason Wiktorowicz
Sales Manager, Positive Energy Solutions | Perth, WA

Jason has been at the centre of Western Australia’s energy transition for over a decade. As Orchestration Lead on Project Symphony — WA’s largest virtual power plant pilot — and Stream Lead on Project Encore, he worked directly with AEMO, Western Power and Energy Policy WA to shape how distributed energy resources connect and operate on the SWIS. That work included developing and rolling out CSIP-AUS, now mandatory for all new WA grid connections. He also led Emergency Solar Management (ESM), the first program of its kind in WA, VPP for Schools (VPP4S), which provided direct market benefits through Supplementary Reserve Capacity, and REBAR, the WA Residential Battery Rebate scheme.

His earlier career spanned Synergy, Infinite Energy and Curtin University’s Sustainability Policy Institute, where he co-authored peer-reviewed research on net-zero urban precincts, solar integration and peer-to-peer energy trading, published in the journal Urban Planning in 2018.

At Positive Energy Solutions, Jason leads sales with a focus on system design accuracy and long-term performance. Positive Energy Solutions installs solar and battery systems, EV chargers and heat pumps, and holds partner accreditations with Fronius, SigEnergy, iStore and SunPower. Connect with him on LinkedIn.