Net Annual Production
The total electricity (kWh) a solar system generates over a full year, accounting for all seasonal variations, weather, and system losses.
Why It Matters
Net annual production is the single most important number for calculating solar savings and payback. It should be verified against the installer's projections after the first year of operation.
Related Terms
Specific Power (kWh/kWp)
The energy output per unit of installed capacity over a period (typically one year). Expressed as kWh per kWp (kilowatt-peak). A good residential system in the U.S. achieves 1,200-1,800 kWh/kWp annually.
Performance Ratio (PR)
The percentage of a solar system's theoretical maximum output that is actually achieved, accounting for all real-world losses (temperature, shading, soiling, wiring, inverter). Typical: 75-85%.
Production Guarantee
A written guarantee from a solar installer specifying the minimum kWh of electricity the system will produce annually. If actual production falls short, the installer compensates the difference.