Work out solar requirement for building instantly with clear inputs, formula shown and shareable results.
Building codes increasingly mandate rooftop solar as a percentage of connected load. The capacity follows directly, panel count is capacity divided by module rating, and daily generation applies peak sun hours with a performance ratio of about 0.8 for inverter, temperature and soiling losses. Roughly eight square metres of roof are needed per kilowatt peak.
Required capacity
kWp = connected load x mandated share
Generation
Daily kWh = kWp x peak sun hours x 0.8 performance ratio
Preliminary estimate only. Mandated solar provision, structural roof capacity and grid connection terms must be confirmed with the authority and a qualified engineer.
kWp = connected load x mandated share. Building codes increasingly mandate rooftop solar as a percentage of connected load.
Panels are rated at 25 °C and 1000 W/m². Real modules run hotter, get dirty, and inverters lose a few percent, so 75-85 percent of nameplate is what is actually delivered.
This calculator takes 4 inputs: Connected electrical load, Mandated solar share of load, Peak sun hours, Panel rating. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.