How the savings are worked out
Bill saving = output × share used at home × usage rate
Feed-in credits = output × share exported × feed-in tariff
Payback = price ÷ yearly saving
Every kWh you use yourself saves the full usage rate on your bill, while exported power earns only the feed-in tariff, often 2 to 7 cents. That is why running the dishwasher, washing machine, pool pump or hot water in the middle of the day makes solar pay back faster.
Yearly output of a 6.6 kW system
| City | Average daily output per kW | 6.6 kW system per year |
|---|---|---|
| Perth | 4.4 kWh | about 10,600 kWh |
| Brisbane, Adelaide | 4.2 kWh | about 10,118 kWh |
| Sydney | 3.9 kWh | about 9,395 kWh |
| Melbourne | 3.6 kWh | about 8,672 kWh |
| Hobart | 3.5 kWh | about 8,432 kWh |
Daily output figures are the typical averages published in the Clean Energy Council's solar consumer guide.
Worked example
A 6.6 kW system at an average 4 kWh per kW per day makes about 9,636 kWh a year. Using 40% at home at 32 cents saves $1,233.41, and exporting the rest at 5 cents earns $289.08: $1,522.49 a year. At $5,500 after the rebate it pays back in about 3.6 years.
The upfront rebate comes from small-scale technology certificates (STCs) under the federal Small-scale Renewable Energy Scheme, and it shrinks each year until the scheme ends in 2030. Installers usually take it off the quoted price.
See what your appliances cost to run with the electricity cost calculator.
Frequently asked questions
How much does a 6.6 kW solar system save a year?
Roughly $1,300 to $1,700 a year at today's prices, depending on your city, how much power you use during the day and your feed-in tariff.
How many kWh does a 6.6 kW system produce a day?
About 23 to 29 kWh a day on average, depending on the city: about 26 kWh in Sydney and 24 kWh in Melbourne.
How long does solar take to pay back in Australia?
Commonly 3 to 6 years for a home system, faster if you use most of the power yourself.
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Last updated October 2026.