Solar Panel Calculator

Estimate the system size (kW) and number of panels needed to offset your energy bill.

Monthly Electricity Usage (kWh)

Target Offset (%)

Peak Sun Hours (per day)

Panel Wattage (W)

Recommended System Size

6.0 kW

How to Size a Solar Array?

To determine the correct size of a solar photovoltaic (PV) system, you must account for system losses (inverters, wiring, dust), which typically reduce efficiency by 20-25% (a 0.78 derate factor).

Daily kWh Required: $$ E_{daily} = \frac{\text{Monthly kWh}}{30} \times \text{Offset} $$ System Size (kW): $$ \text{kW} = \frac{E_{daily}}{\text{Peak Sun Hours} \times 0.78} $$