We advise people to install a system that’ll generate at least ½ your Winter daily usage. If you can install a larger system, that will probably be beneficial (depending on your energy use), and you will be more likely to still receive a feed-in tariff during the Winter. If you think you might like to have a battery in future, then ideally your system will be 5kW or larger.
Most homes have an average daily usage of 14-15 kWh
1kW of solar panels will generate approximately 4kWh of electricity p/day
So, a 5kW solar system will generate about 20kWh on a clear, sunny day
A typical 2021 system will pay for itself within 3-5 years (in the form of lower bills).
Typical costs for a 5kW system are currently:
$5500-8000 (with a single inverter for the entire system - works less efficiently, but this may not be an issue on a north-facing roof with no shading)
$8000-9500 (with individual inverters on every panel - more efficient but more expensive)