Most homeowners we visit in Dee Why, Mona Vale and Charlestown want one number: how many years until the system pays for itself. For a well-sized solar-only setup in NSW that's typically 3 to 5 years, and a solar-plus-battery system usually lands between 6 and 9 years once you factor in the current rebates.

Solar-only payback: the quick win

A quality 6.6kW system installed in Sydney runs roughly $5,500 to $8,500 after the federal STC rebate, depending on panel and inverter brand and the difficulty of the roof. A 10kW system sits closer to $9,000 to $13,000. The STC discount is applied at the point of sale, so you don't chase it later - but the value of those certificates steps down each year, so the rebate is worth slightly less every January.

On a typical Northern Beaches home with a $400-$600 quarterly bill, a 6.6kW system offsets $1,200 to $1,800 a year. That's where the 3-to-5-year figure comes from. The single biggest factor in your favour is self-consumption: every kilowatt-hour you use while the sun's up is worth 25-35c off the grid, versus the 4-7c feed-in tariff you now get for exporting it.

Feed-in tariffs have fallen hard over the last few years. Designing a system to export big volumes no longer makes sense - we size for what you actually use during daylight, and shift loads like the dishwasher, pool pump and hot water onto a daytime timer where we can.

Battery payback: longer, but the incentive helps

A battery stores your cheap daytime solar so you're not buying expensive grid power at night. The catch is that batteries cost more per dollar saved than panels. A 10kWh battery is roughly $9,000 to $14,000 installed before incentives, and on its own it might only save $600 to $1,000 a year.

That's why the NSW battery incentive matters. It knocks a meaningful chunk off the upfront cost, and there's an additional benefit if you connect the battery to a Virtual Power Plant afterwards. Run the maths with the incentive and a properly sized battery and payback drops from over a decade down to that 6-to-9-year range - well inside the 10-year warranty on most quality units.

Our honest view: get the battery if you want overnight independence, blackout backup and protection against rising grid prices, and you've got the daytime solar to actually fill it. If the only goal is the fastest possible payback, solar alone wins. The incentive narrows that gap considerably, which is the reason to act while it's on the table rather than waiting.

What actually changes your payback

Three things move the number more than panel brand ever will. First, your usage pattern - a household home during the day pays off solar faster than one that's empty until 6pm. Second, your network: Ausgrid and Endeavour both have export limits that can cap a large system, especially in pockets with constrained infrastructure. Third, your roof - shading from a single neighbouring gum tree across an afternoon can cost you 15-20% of a string's output.

Here's the tradesperson detail most quotes skip: your switchboard. Plenty of older Northern Beaches homes still have ceramic fuses or no main switch rated for the job, and many don't have room for the extra breakers a solar and battery install needs. Sorting that out can add $800 to $2,500, and a quote that ignores it isn't a real quote. We also check whether your meter is a single-phase or three-phase setup and whether it needs reconfiguring for solar - a metering reconfiguration delay can hold up your first export credit for weeks if it's not booked early.

The most common installation mistake we're called to fix is an oversized inverter paired with an undersized cable run, or panels crammed onto a shaded west face just to hit a headline kW figure. Both wreck your real-world output and quietly blow out the payback you were promised.

A realistic example

Take a Frenchs Forest family on Ausgrid, $550 a quarter, mostly evening usage. A 10kW solar system at around $11,000 saves them roughly $1,600 a year - call it a 7-year payback on solar alone, faster if they shift more load to daytime. Add a 13kWh battery with the NSW incentive applied, and the combined system pays back in about 8 years while cutting their grid bill close to zero and keeping the lights on through outages.

Those figures shift with your roof, your network limits and how the rebates stand when you sign. The general shape holds: solar pays back quick, battery pays back slower but the incentive currently makes it sensible.

Get your own numbers

Payback is specific to your bill, roof and switchboard - generic online calculators ignore the gotchas that cost real money. We'll come out, check your meter and board, look at shading and your daily usage, and give you honest figures with the current rebates already factored in.

Book a free on-site assessment with Impressive Electrical & Solar and we'll tell you exactly what your payback looks like before the incentive steps down.