The question we get most on the Northern Beaches is simple: "Is my solar still pulling its weight, or am I throwing money away?" If your system is six or more years old, the honest answer is usually that it could be doing a lot more for you – and the fix is often cheaper than a full replacement.

Here's how we read the signs on a quote visit, what's actually worth spending money on, and what we'd leave alone.

The clearest signs it's time

Your output has dropped. If your app or meter shows you're generating noticeably less than a few summers ago for the same weather, panels or wiring are degrading. Good panels lose roughly 0.5% a year, so a 5–10% drop over a decade is normal – a 30% drop is not.

Your inverter keeps tripping or faulting. String inverters typically last 10–12 years. If yours is throwing isolation or grid-fault errors, restarting constantly, or has gone silent, that's the single most common reason a system underperforms in Sydney.

You're exporting most of your power for 4–7c/kWh. Feed-in tariffs have collapsed across Ausgrid and Endeavour networks. If you're sending the bulk of your generation to the grid during the day and buying it back at 35–45c at night, your system is sized for an era that's gone.

Your system is small. A 1.5kW or 3kW system from 2013 made sense then. Today most Dee Why and Mona Vale homes we visit use far more – air con, a heat pump, maybe an EV – and a 6.6kW or 10kW system pays for itself faster than ever.

The metering and switchboard gotchas

Here's something only an installer tends to flag: a lot of older systems were never reconfigured for net metering. We still find homes on a gross meter, or with an old import-only meter, where the solar isn't being credited properly at all. If you've never seen a feed-in credit on your bill, that's the first thing we check.

The other one is the switchboard. Plenty of homes in Frenchs Forest and Charlestown still have ceramic fuses or no main switch for the solar supply, which doesn't meet current standards. If we're adding capacity or a battery, the board often needs an upgrade first – budget $800–$2,500 depending on what's there. We'd rather tell you that on the quote than surprise you on install day.

A common mistake we inspect for: panels installed flat or facing the wrong way to suit the roof rather than the sun, and DC isolators mounted in full weather without proper enclosures. Cracked, water-ingressed isolators are a known fire risk on older jobs and a clear sign the original install was rushed.

Repair, upgrade, or replace?

If your panels are sound but the inverter has died, a straight inverter swap is the cheapest path – usually $1,500–$3,000 for a quality replacement. We'll match it to your existing array and check the strings are still healthy first.

If your system is small and the panels are old, replacing the lot often makes more sense than patching it. New panels are far more efficient per square metre, and the federal STC rebate still knocks several thousand dollars off a new install – though that subsidy steps down each year and ends in 2030, so the discount shrinks the longer you wait.

If your panels are fine and you're just bleeding value to cheap feed-in tariffs, the real upgrade is a battery, not new solar. Storing your midday generation and using it at night is where the savings now sit.

Is a battery the actual upgrade you need?

For most homes we visit with a working 5–10kW system, the answer is yes. With the NSW battery incentive cutting upfront cost and feed-in tariffs as low as they are, self-consuming your own power is the strongest return going.

One catch worth knowing: not every old inverter is battery-ready. Some need a separate hybrid inverter or an AC-coupled battery, which changes the price. We check inverter compatibility on the spot so you're not quoted for something that won't physically work with your setup.

A realistic ballpark for a quality battery in Sydney is $8,000–$14,000 installed after incentives, depending on capacity and whether the switchboard needs work. We'd always size it to your actual evening usage rather than sell you the biggest unit on the shelf.

Get a straight answer on your system

If any of this sounds like your setup – dropping output, a tired inverter, tiny export credits, or a switchboard that's seen better days – it's worth a proper look before you spend on anything new. We'll inspect the panels, inverter, metering and board, tell you what's genuinely worth upgrading, and what we'd leave alone.

Book a free on-site assessment with Impressive Electrical & Solar across Sydney, the Northern Beaches and Newcastle, and we'll give you the honest version.