Solar vs Grid Electricity: What 10 Years of Doing Nothing Actually Costs an Australian Home

Written by Bec Ramirez·Published 16 May 2026·9 min

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Most people compare solar quotes the same way they compare TVs. Cheapest one wins, get it installed, move on with life.

Almost nobody compares quotes against the alternative. What the next 10 years of grid bills will actually cost you if you do nothing at all.

That is the bit that goes missing from every conversation I have with homeowners. They will spend three weekends agonising over a $500 difference between two quotes, then casually accept paying close to $28,000 to their electricity retailer over the next decade like it is just weather.

It is the renting vs mortgage decision, basically

Here is the framing that I think makes the most sense.

Staying on grid electricity is renting. Every month, you pay the retailer for power, you get nothing at the end of it, and the rent goes up roughly every year. You do not own anything. You are not building toward anything. You are just keeping the lights on.

Putting solar on the roof is more like a mortgage. There is an upfront cost (much smaller than people think in May 2026, but still a cost). After that, the monthly outgoing drops dramatically. Eventually the system pays itself off and the savings keep coming for another 15 plus years. You actually own the thing that is producing your power.

Renters do not get a payback period because they never owned the asset. That is not a criticism of renting a house. But applying the same logic to your electricity is worth thinking about....

The 10-year cost of doing nothing

Let us do the maths on the "do nothing" scenario first, because that is the number that most homeowners never bother calculating.

A typical NSW household uses around 16 to 18 kWh per day. At current Default Market Offer rates of around 33 to 38 cents per kWh, plus daily supply charges of around $1.20, that comes out to roughly $2,200 in year-one bills. Some households higher, some lower, but $2,200 is a reasonable midpoint for a family home.

Now apply electricity price inflation. The Australian Energy Regulator increased the Default Market Offer by 8.5 per cent in 2023 and 21 per cent in 2024. The 2025 increase was smaller, around 7 per cent. There is no scenario where prices reverse. Networks are being upgraded, ageing coal plants are being replaced, and integrating renewables costs real money.

Even using a conservative 5 per cent compounding assumption (which is well below what the last 5 years actually delivered), a $2,200 bill in year one becomes:

• Year 5: about $2,810
• Year 10: about $3,580

Sum the lot up across the decade and you get a total electricity outgoing of approximately $27,800. That is the cost of doing absolutely nothing. The cost of being a renter on the grid for the next 10 years.

And that figure is conservative. Use the actual 5-year tariff trajectory (closer to 8 per cent per year on average) and the 10-year total runs north of $34,000.

What the solar side of the ledger looks like

Here is where it gets interesting. In May 2026, the cost of getting solar on the roof in NSW is the lowest it has ever been in real dollars.

A quality 6.6 kW system in NSW typically costs $4,500 to $7,500 out of pocket after the STC rebate is applied at point of sale. Add a 10 kWh battery and the federal Cheaper Home Batteries rebate ($372 per kWh) plus the NSW Peak Demand Reduction Scheme credit takes a combined solar plus battery package down to surprisingly low numbers. Some households qualify for genuine zero-upfront packages through the NSW solar plus battery rebate program.

A 6.6 kW system in Sydney generates around 27 kWh per day on average across the year. Without a battery, a typical household self-consumes 30 to 40 per cent of that (the rest gets exported for a small feed-in tariff). With a 10 kWh battery, self-consumption jumps to 70 to 90 per cent, and the bill savings get serious.

Realistic year-one bill outcomes for a NSW household:

• 6.6 kW solar only: bill drops from around $2,200 to around $600 to $900 (savings of $1,300 to $1,600)
• 6.6 kW solar plus 10 kWh battery: bill drops to $100 to $400 (savings of $1,800 to $2,100)

Those savings also compound, because the unit price of grid electricity keeps rising. Each year the same amount of self-consumed solar is worth more in avoided bill. By year 10, a system that saved $1,600 in year one is saving closer to $2,600.

Side by side over 10 years

Even on conservative numbers, the solar plus battery position is roughly $20,000 ahead of the do-nothing position over the decade. The solar-only position is $12,000 ahead. Both stay ahead well beyond year 10, because the panels keep generating for another 15 to 20 years and the savings keep compounding.

But what if I sell the house before payback?

Common worry, and the answer is reassuring.

A working solar system lifts a property's sale price by more than the remaining payback amount in most cases. Multiple Australian property data analyses have shown solar-equipped homes selling for $5,000 to $20,000 above comparable non-solar homes, depending on system size and whether a battery is included.

So even if you sell in year 3 of a 6-year payback, the system has typically already paid itself back through the sale price uplift, and you have had three years of reduced bills on top.

The other thing worth saying: solar plus battery is increasingly becoming an expected feature for buyers in the $700k plus bracket. The market is gradually moving from "nice extra" to "why does this place not have it." That trend will only accelerate as electricity prices keep rising.

What the quote does not tell you

Going back to the opening point. When you compare solar quotes, you are comparing how much you pay today to a solar installer. That is one number, and it matters.

But there is a second number that nobody is putting in front of you. The amount you pay your electricity retailer over the next 10 years if you decide not to act. For a typical NSW household, that is the better part of $30,000. Going up.

The solar quote is not the cost of solar. The solar quote is the cost of stopping the meter from going up at the rate it has been for the last 5 years and is forecast to keep going.

Renting or buying. That is the actual decision.

If you want to see what the numbers look like for your specific home (your usage, your roof, your suburb), the easiest way is to get a couple of quotes and put them next to your last 4 quarters of electricity bills. The maths usually tells its own story. See what rebates apply for your state if you want to start there first.

Written by

Bec Ramirez

Aussie Mum & Energy Expert

Helping families navigate the switch to solar with practical, real-world advice. Bec focuses on the financial side — rebates, bill savings, and financing options — so everyday Australians can see real value from going solar.

Learn more about Bec Ramirez