Size a rooftop solar array from consumption, sun hours and panel rating.
Peak sun hours already fold in latitude and climate, so annual yield per installed kilowatt is a single multiplication. System losses of around 18 per cent are typical and cover inverter, temperature and soiling effects. Offsetting much beyond annual consumption rarely pays unless export rates are favourable, because the surplus is sold at far less than the retail price avoided.
Solar Panel
Annual yield per kW = peak sun hours × 365 × performance ratio
Annual yield per kW = peak sun hours × 365 × performance ratio Peak sun hours already fold in latitude and climate, so annual yield per installed kilowatt is a single multiplication. System losses of around 18 per cent are typical and cover inverter, temperature and soiling effects.
Offsetting much beyond annual consumption rarely pays unless export rates are favourable, because the surplus is sold at far less than the retail price avoided.
This calculator takes 5 inputs: Annual electricity use, Average peak sun hours, Panel rating, System losses, Share of use to offset. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.