How Many Solar Panels Do I Need For My Home?

The honest answer to 'how many panels' starts with a different question: how many units of electricity does your home actually consume in a year? Your monthly bill, divided by your effective tariff, gives a workable estimate of annual consumption in kWh.

Once you know annual consumption, divide it by the annual generation a single kilowatt of capacity delivers at your location. In much of northern India this lands somewhere in the region of 1,300–1,500 kWh per kW per year, before shading and system losses are applied.

That gives you system capacity in kW. Panel count is then simply capacity divided by the wattage of the module used. With 550 W modules, a 5.5 kW system needs roughly ten panels, plus allowance for spacing, walkways and service access.

Roof area becomes the constraint only when it is smaller than what the required capacity needs. If that happens, higher-efficiency modules or a re-scoped system size are the usual answers.