How the calculation works
System size (kW) = daily energy ÷ (peak sun hours × efficiency). Number of panels = system size × 1,000 ÷ panel watts.
Frequently asked questions
How much roof space do I need?
About two square metres per panel, so ten 400 W panels need around 20 m².
What are peak sun hours?
The hours per day with sunshine equal to full strength. Many sunny regions see about 4 to 6.