A 3kW system may suit a smaller home with modest daytime electricity use, while 5kW or 6.6kW systems generally provide more generation for larger households, higher usage or future electrification. The right size depends on your electricity bills, roof space, panel orientation, shading, budget and whether you plan to add a battery, electric vehicle or heat pump. Your distributor may also apply export limits, so a larger system does not always mean you can send all surplus power to the grid. Ask an accredited solar installer for a design based on your interval usage data and local network rules.