The ratio of photovoltaic panels to roof area

Here’s an easy calculation you can do: Multiply the square footage of your roof by .75 to account for the required solar setback. (More on that below.). Here’s an easy calculation you can do: Multiply the square footage of your roof by .75 to account for the required solar setback. (More on that below.). A standard 4kW solar PV system requires about 20 m² of roof space, resulting in approximately 150-170 kWh per m² of installed roof area annually. [pdf]

Which PV inverter ratio should I choose

DC/AC ratio refers to the output capacity of a PV system compared to the processing capacity of an inverter. It’s logical to assume a 9 kWh PV system should be paired with a 9 kWh inverter (a 1:1 ratio, or 1 ratio). A PV to inverter power ratio of 1.15 to 1.25 is considered optimal, while 1.2 is taken as the industry standard. [pdf]