The calculator estimates energy needs from the appliances you select and the backup duration you choose. It uses typical assumed running wattage and duty-cycle values to estimate average energy consumption over time, then applies an allowance for system losses to estimate the usable battery capacity required.
Running load is the power an appliance typically draws while operating. Some equipment, especially motors and compressors, may briefly draw more power when starting. A battery system's inverter must be able to handle both continuous load and relevant startup surges. Energy capacity in kWh alone does not establish that the system can start or run every selected appliance.
Appliance wattage, duty cycles, system efficiency, battery usable capacity, and surge behavior vary by model and real-world conditions. The calculator uses simplified assumptions and does not inspect your equipment, wiring, electrical panel, climate, solar input, or installation conditions. It does not calculate a final electrical design, guarantee runtime, or confirm code compliance.
Use the result as a preliminary planning estimate only. Before buying equipment, ask a qualified installer or electrician to verify appliance loads, inverter continuous and surge ratings, usable battery capacity, transfer equipment, permits, and installation requirements.