§ 06 — Home

How fast do panels actually pay themselves off?

Australian solar payback times have shrunk from a decade to 4–6 years thanks to higher grid prices and lower install costs. Plug your bill, postcode and system size below and we'll work out the cash flow over 25 years.

Updated · Mar 2026·Source: BoM · AER · Clean Energy Council·Read · 6 min

Your inputs

System size

Most AU residential installs sit between 6.6 kW and 10 kW.

Capital city · for irradiance

Grid rate

¢/kWh

Feed-in tariff

¢/kWh

Daytime self-use

40%

Share of solar you use yourself (rest exported).

System cost (incl. install, after STCs)

Inputs local. Nothing sent anywhere.

The result

Payback in approximately

5.2 years

Then ~$1,384/year of free electricity for ~20 more years

Annual generation: 8,191 kWh
Bill offset / year: $1,065
Export revenue / yr: $319
25-year net return: $25,406

§ Cumulative cash flow · every 5 years
Year	Annual saving	Cumulative	Position
1	$1,384	−$5,816	paying off
5	$1,357	−$348	paying off
10	$1,323	$6,335	in the black
15	$1,290	$12,852	in the black
20	$1,258	$19,208	in the black
25	$1,227	$25,406	in the black

Generation estimates use Bureau of Meteorology mean daily irradiance per capital city × a 0.85 system-loss factor. We assume a 0.5%/year panel degradation and a flat grid rate (in reality grid rates have outpaced CPI for a decade, which makes solar look even better than this simple model).

Why payback got so much faster

A residential solar system in 2026 generates the same kilowatt-hours as it did in 2016 — but the financial calculation has flipped twice in that time. The hardware costs less, and the grid electricity it offsets costs more.

A 6.6 kW system installed under the federal Small-scale Technology Certificate (STC) scheme now lands at ~$5,500–8,000 after rebate. Grid electricity in most states has climbed past 30¢/kWh. Together, the maths now favours payback windows of 4–6 years rather than the 10+ years common a decade ago.

The single biggest variable in your own case isn't system size — it's self-consumption. Every kWh you use yourself is worth your full grid rate (~32¢), but every kWh you export is worth your feed-in tariff (~5–10¢). Pairing solar with a battery, an EV, or a daytime workload is what turns a 6-year payback into a 4-year one.

Daily irradiance · capital cities

City	Avg kWh/kW/day	6.6 kW per yr
Darwin	4.8	11,563 kWh
Perth	4.6	11,082 kWh
Brisbane	4.5	10,841 kWh
Adelaide	4.4	10,600 kWh
Canberra	4.2	10,119 kWh
Sydney	4.0	9,636 kWh
Melbourne	3.8	9,156 kWh
Hobart	3.5	8,432 kWh

Source: Bureau of Meteorology · north-facing

§ Letters & replies

Solar, answered.

Common questions about residential solar economics in Australia.

Should I add a battery?+ open

As of 2026 the maths is borderline. A 10 kWh battery costs ~$10–13k installed and pays back in ~10–12 years — close to the battery's warranty period. State subsidies (e.g. VIC's interest-free loan) can swing this. Without one, panels alone still pay back in 4–6 years.

What about feed-in tariff cuts?+ open

Feed-in tariffs have been falling — from 60¢/kWh in 2009 to ~5–8¢ today, and some retailers are moving to 0¢ at peak generation hours. That makes self-consumption (or pairing with a battery/EV) the lever that matters most for new installs.

Does direction and shade really matter?+ open

A lot. North-facing panels generate ~20% more than east/west; even 10% shade on a string can halve production. East/west splits can actually be better than pure north if your usage skews to mornings and evenings.

How long do panels last?+ open

Modern panels carry 25-year performance warranties (typically guaranteed 80% output at year 25). Inverters are the weak link — most last 10–15 years and a replacement costs ~$1,200–2,500.

Next: pair it up

§ 04 — Vehicle

How fast do panels actually pay themselves off?

Why payback got so much faster

Solar, answered.

Next: pair it up

EV vs petrol

Mortgage repayments

Salary take-home