The 10kW off-grid solar system is considered a magic number for a simple reason: in Australia, the average household requires 16-20kWh of power per day. Taking the winter average solar panel production in a region like Ballarat, Victoria, as an example, one kW of solar panels produces around 2kWh of electricity per day. In off-grid living, the target is not the average solar production throughout the year, but rather the winter period, which is the time of lowest solar energy generation. As a result, 20 / 2 = 10kW. It’s important to note that rebate systems actually encourage the installation of more solar panels, as any extra panels generate additional rebates. Interestingly, a 10kW power inverter is also a good number for most households. When connecting a house to the grid, for example in Ballarat, the power company will allow a maximum demand of 40A, which is roughly equivalent to 10kW. Additionally, a battery bank of around 10kWh would be suitable as well, as it covers half a day of demand, but 10kWh would be the absolute minimum for a battery bank.