Practical guide
Turn backup device loads into daily energy
LoadDay Power Planner separates energy use from instantaneous power. Start with the devices that matter during the planning window and use measured or documented inputs.
Keep running and surge fields distinct
Running watts describe ongoing energy use. Surge watts describe a peak input used for inverter review, so enter a peak at least as high as the running value when the source provides one.
daily Wh = running watts x hours per day
Read the default load list
The illustrative router contributes 20 W for 24 hours, the laptop contributes 60 W for 8 hours, and the fan contributes 45 W for 6 hours. Together the engine reports 1,230 Wh per day and a 125 W running load.
The laptop alone contributes 60 x 8 = 480 Wh in this scenario.
Keep priorities visible
Mark essential and comfort rows so a planning discussion can remove or add a load without rewriting the calculation. A cycling device should use a measured average or a clearly labeled estimate.
Check your own scenario
Replace the illustrative inputs with measured values and dated specifications.
Open LoadDay Power PlannerMethod and references
Read the full calculation method and its limits
- U.S. Department of Energy home energy worksheet
- U.S. Consumer Product Safety Commission generator and carbon monoxide safety
Method and examples reviewed 2026-09-30. Examples are illustrative; input values and specifications are not independently verified.