🔆 Array Size Calculator for Solar & Energy
Estimate array capacity for an energy target.
This free tool helps you turn project measurements into a practical planning estimate. Enter values in Vaelden’s interactive calculator, review the result, and confirm important assumptions against supplier data, measurements, codes or qualified advice before committing materials or money.
Open the Array Size calculator →
How to calculate array size
Method: Required array capacity = daily energy target ÷ peak-sun hours ÷ system efficiency
- Start from measured consumption or the portion you realistically want solar to cover.
- Use annual-average solar resource for a first-pass size.
- Check roof area, orientation, export limits and inverter constraints before choosing panels.
Worked example
Using these planning inputs:
- Daily energy target: 24 kWh/day
- Peak sun hours: 4.2 h/day
- System yield: 80 %
Indicative array size: 7.14 kW
Reality check: An energy-matched array is not automatically the best financial design; daytime load shape and export tariffs matter.
Method status and references
Screening model. This reverses the simple peak-sun-hours estimate. It does not replace site weather, roof, network or equipment modelling.
Before you calculate
Use consistent units and the best measured inputs available. Real materials, equipment, site conditions and tolerances can change the result. Vaelden shows planning estimates; regulated, structural, electrical, plumbing, pressure and other safety-critical work still requires appropriate local compliance and professional advice.