Calculate the real output of a panel after temperature, soiling and age derating.
Panels are rated at 25 °C but run far hotter in sunlight, so a 45 °C cell temperature alone costs about 7 per cent. Degradation adds roughly half a per cent per year permanently. Hot climates deliver less output per installed watt than temperate ones despite more sunshine, which is why temperature coefficient matters when selecting panels.
Solar Panel Output
Output = rated × (1 − temperature loss − degradation − soiling)
Output = rated × (1 − temperature loss − degradation − soiling) Panels are rated at 25 °C but run far hotter in sunlight, so a 45 °C cell temperature alone costs about 7 per cent. Degradation adds roughly half a per cent per year permanently.
Hot climates deliver less output per installed watt than temperate ones despite more sunshine, which is why temperature coefficient matters when selecting panels.
This calculator takes 5 inputs: Panel rated power, Cell temperature, Temperature coefficient, Soiling loss, Panel age. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.