Sizing a solar system for a small business starts with understanding annual electricity consumption measured in kilowatt-hours (kWh). A simple way to estimate is to review 12 months of utility bills to calculate average monthly and annual use. Once you have annual kWh, divide by the expected annual kWh produced per kW of solar in your location (often between 1,000–1,600 kWh per kW depending on sun exposure and climate).
For example:
Factors that influence system size include roof or site space, orientation and shading, peak demand needs, recommended offset percentage (e.g., cover 50–100% of use), and budget.
A professional site assessment is recommended because roof condition, structural capacity, and electrical panel limitations can affect feasible system size. Many businesses also evaluate partial coverage or phased systems to match cash flow and operational needs.