Solar Sizing Calculator – Rooftop PV Capacity & Panel Estimate
Use the solar sizing calculator to perform a quick preliminary calculation from project dimensions and engineering assumptions. Review inputs and verify final results against project requirements.
Introduction
Estimate preliminary rooftop solar capacity from electricity consumption and solar-resource assumptions, helping users understand approximate panel and system requirements.
Basic Solar Sizing
A simplified sizing approach relates required energy production to average daily consumption, solar irradiation or peak-sun-hour assumptions and system losses.
System Losses
PV output is affected by temperature, inverter efficiency, wiring losses, shading, dust, orientation and module degradation. A practical sizing calculation should include an overall performance factor.
Panel Count
Once the required DC capacity is estimated, panel count can be approximated by dividing system capacity by the nominal wattage of one panel, then rounding up.
Rooftop Constraints
Available roof area, orientation, tilt, shading, structural capacity and local grid rules can limit the practical system size.
FAQs
Q: Does higher panel wattage always mean a smaller system? A: It may reduce panel count, but total system capacity is still determined by energy demand and site conditions.
Q: Does this calculate exact annual generation? A: No. Detailed generation requires location-specific solar data and system modelling.
Disclaimer
Use the result for preliminary planning. Final PV design should include site survey, shading analysis, electrical protection, structural review and applicable utility requirements.